FOUS11 KWBC 261817
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
117 PM EST Thu Feb 26 2026

Valid 00Z Fri Feb 27 2026 - 00Z Mon Mar 02 2026


...Cascades & Northern Rockies...
Days 1-2...

Strong westerly mid and upper level flow across the Northwest
will direct modest moisture into the upslope terrain of the WA
Cascades and northern Rockies through Friday before flow turns
more northwesterly and drier by late in the day on Saturday. Snow
levels are forecast to remain around 2000-3000ft across the region
before dropping below 2000ft across northwest MT on Saturday as a
strong cold front dives southward and increases precipitation late
Day 1 and early on Day 2. WPC 48-hr probabilities for at least 8"
of snow remain high (70-90%+) above about 4000ft in the northern
WA Cascades and the Lewis Range/Glacier National Park region of
northwest MT.


...Northern Plains...
Day 2...

A cold front will dive out of Canada and sink rapidly southward
Friday, reaching the Central Plains by Friday night. As this front
continues south, a modest 700mb trough will dive E/SE along the
front, pushing modest WAA atop the boundary and into the Northern
Plains beginning Friday evening in the High Plains of Montana and
then continuing E/SE through the Upper Midwest by Saturday evening.
This will result in modest 295K isentropic ascent into near-
normal PWs to support expanding precipitation. This precipitation
will likely manifest as a narrow channel with moderate to heavy
snow rates as a dynamic jet structure arcs overhead enhancing the
700-600mb fgen to provide lift directly into the deepening DGZ.
This should create a narrow band of snow translating along its long
axis, leading to a long duration of moderate snowfall rates from
eastern MT through southern WI before weakening as it ejects
eastward Saturday night. WPC probabilities are moderate (50-70%
chance) for at least 2 inches of snow, with locally higher amounts
above 4 inches possible (10-30%), highest across the Dakotas.


...Central Plains into the Mid-Mississippi Valley...
Day 3...

Broad ridging over the West is progged to become suppressed
somewhat on Sunday as a shortwave emerges from the Pacific and
races quickly over the top of this ridge. As this shortwave moves
into the Central Plains Sunday morning, it will move atop the low-
level baroclinic zone accompanying a surface cold front to produce
a wave of low pressure and accompanying increased ascent. Most of
this lift will be produced via isentropic upglide, especially along
the 290-295K surfaces, with the driving WAA pushing a warm nose
northward atop the cold dome to the north. While there is still
quite a bit of uncertainty into both northward latitudinal advance
of precipitation, as well as timing of the heaviest rates, there is
increasing confidence in a swath of mixed snow/sleet/freezing rain
spreading into the Central Plains late Sunday. Although
adjustments in the forecast are likely, current WPC probabilities
indicate a 10-30% chance for at least 2 inches of snow from
eastern KS/NE through southern IA and northern MO, with freezing
rain exceeding 0.01 inches possible (10-30%) chance just to the
south of the heaviest snowfall.


Weiss/Miller




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FOUS11 KWBC 270817
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
317 AM EST Fri Feb 27 2026

Valid 12Z Fri Feb 27 2026 - 12Z Mon Mar 02 2026


...Northwest Montana...
Day 1...

Continued strong westerly mid and upper level flow across the
Northwest will direct modest moisture into the upslope terrain of
the WA Cascades and northern Rockies today before flow turns more
northwesterly and drier by Saturday. Snow levels are forecast to
remain around 2000-3000ft across the region before dropping below
2000ft across northwest MT on Saturday as a strong cold front dives
southward and increases precipitation late tonight, while
precipitation coverage drops throughout today across the far
northern WA Cascades. WPC probabilities for at least 8" of snow
remain moderate (50-70%) above about 4000ft in the Lewis
Range/Glacier National Park region of northwest MT.


...Northern Plains...
Days 1-2...

A cold front will dive out of Canada and sink rapidly southward
Friday, reaching the Central Plains by tonight. As this front
continues south, a modest 700mb trough will dive E/SE along the
front, pushing modest WAA atop the boundary and into the Northern
Plains beginning Friday evening in the High Plains of Montana and
then continuing E/SE through the Upper Midwest by Saturday evening.
This will result in modest 295K isentropic ascent into near-
normal PWs to support expanding precipitation. This precipitation
will likely manifest as a narrow channel with moderate to heavy
snow rates as a dynamic jet structure arcs overhead enhancing the
700-600mb fgen to provide lift directly into the deepening DGZ.
This should create a narrow band of snow translating along its long
axis, leading to a long duration of moderate snowfall rates from
eastern MT through southern WI before weakening as it ejects
eastward Saturday night.

There remains some latitudinal spread in guidance regarding the
location of this band, but CAMs and recent global guidance
highlight a maximum localized corridor of 4-8" is possible. This
WAA fgen scenario usually tends to favor more northern solutions,
but that is highly dependent on the tightening thermal gradient
and overall amplitude should the higher-end scenario occur. Recent
short-term HRRR trends are for a more amplified western U.S. ridge,
which is why the 06z HRRR (and even 06z NAM) trended north and
heavier with its snowfall axis. Given the spread and very narrow
snow band, ensemble probabilistic guidance remains quite low, but
the strong fgen collocated with SLRs around 20:1 support a high-
end snowband potential. WPC probabilities are moderate (50-70%
chance) for at least 2 inches of snow from southwest ND to southern
WI, with locally higher amounts above 4 inches possible (10-30%),
highest across the Dakotas and southern Minnesota. Should guidance
come into better agreement regarding placement of this snowband,
expect these probabilities to increase.


...Central Plains into the Midwest...
Day 3...

Broad ridging over the West is progged to become suppressed
somewhat on Sunday as a shortwave emerges from the Pacific and
races quickly over the top of this ridge. As this shortwave moves
into the Central Plains Sunday morning, it will move atop the low-
level baroclinic zone accompanying a surface cold front to produce
a wave of low pressure and accompanying increased ascent. Most of
this lift will be produced via isentropic upglide, especially along
the 290-295K surfaces, with the driving WAA pushing a warm nose
northward atop the cold dome to the north. While there is still
quite a bit of uncertainty into both northward latitudinal advance
of precipitation, as well as timing of the heaviest rates, there is
increasing confidence in a swath of mixed snow/sleet/freezing rain
spreading from the Central Plains into the Midwest late Sunday
into early Monday. Although adjustments in the forecast are likely,
current WPC probabilities indicate a 20-40% chance for at least 2
inches of snow from southern IA and northern MO to central/northern
IL, with light freezing rain possible just to the south of the
heaviest snowfall. Current freezing rain probabilities for
exceeding 0.1" are low (<10%) across northeast KS.


Snell



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FOUS11 KWBC 271902
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
202 PM EST Fri Feb 27 2026

Valid 00Z Sat Feb 28 2026 - 00Z Tue Mar 03 2026


...Northern High Plains, Great Lakes, & Northeast...
Days 1-3...

Guidance continues to indicate a long, narrow, corridor of
moderate to heavy snow will develop this evening over eastern
Montana and then track rapidly E/SE into the Great Lakes by Sunday
morning.

This swath of snowfall is expected to develop north of a cold front
which will be steadily digging southward into the Central and
Southern Plains on Saturday. As this front pushes south, a modest
mid-level trough will dive along the boundary, leading to
downstream WAA and accompanying 295K isentropic ascent to support
expanding precipitation. At the same time, impressive 850-600mb
fgen will develop and elongate NW to SE in response to this WAA
atop the front combined with the favorable positioning of the upper
jet streak to drive intense lift across the area. While there is
still uncertainty into where exactly this band of precipitation
will set up (still considerable latitudinal variability in the axis
from the various models) the result is likely to be a corridor of
heavy snow rates which could exceed 1"/hr (20-40% chance).

Since the snowfall should translate along the long axis of this
band, it will enhance the duration of snowfall, leading to the
potential for significant accumulations. Despite the latitudinal
uncertainty in this band placement, the high-res is actually in
pretty good agreement in amounts, with a general 2-4 inches likely,
with local amounts above 6" possible as reflected by WSE plumes.
While the fgen is impressive and the DGZ is deep, there is some
concern they won't overlap perfectly to create locally much higher
snowfall. However, this deep DGZ and a cold column should produce
high SLRs and fluffy snow that will quickly accumulate,
additionally suggesting the potential for locally higher totals. In
general WPC probabilities are moderate (30-50%) for 4+ inches from
western ND through the Coteau des Prairies and Buffalo Ridge of
SD/MN D1, with a low risk for more than 6 inches in isolated
locations. Farther east D2 and then D3, the band of snowfall should
weaken (WPC probabilities for 4+ inches fall to just around 10% D2
across the Great Lakes) before expanding a bit with some enhanced
WAA ahead of the front across the Northeast D3.


...Central Plains into the Mid-Atlantic...
Days 2-3...

Broad ridging across the Southwest will get suppressed as a
shortwave tracks out of the Pacific, crests the ridge Sunday
morning, and then continues E/SE into the Central Plains Sunday
afternoon. This shortwave will be paired with an upper jet pushing
eastward, and both of these features will continue to track east
into the Mid-Atlantic states on Monday. As this evolution develops
aloft, a surface cold front will drop steadily southeast from the
Central Plains into the Southeast by Monday. The overlap of this
front with the upper evolution will result in a weak wave of low
pressure moving along the boundary.

Downstream of this wave of low pressure, warm and moist advection
will begin to increase, leading to expanding and intensifying
isentropic upglide, especially along the 290K and 295K surfaces.
The downstream low-level flow reaching 20-30 kts at 850mb will help
surge modest IVT (approaching 400 kg/m/s) to drive PWs above the
90th climatological percentile in some areas, leading to a region
of heavy precipitation. The accompanying WAA will likely push a
warm nose northward to transition precipitation from snow, to mix,
to rain from the Central Plains into the Mid-Mississippi Valley
Sunday into Monday. This precipitation will then extend into the
Mid- Atlantic Monday as a wedge of high pressure extends down the
coast, leading to at least some light mixed precipitation across
the Mid- Atlantic states, although dry air within the wedge could
erode a lot of the moisture before it arrives.

WPC probabilities for snowfall peak around 10-30% for 2+ inches of
snowfall across parts of MO/IA/IL D3, but the threat has diminished
somewhat with new updates. However, the accompanying freezing rain probabilities have increased, and are now more than 50% for at
least 0.01 inches of ice D2 in the Mid-Mississippi Valley and
Central Plains, and increase/expand across the Central Appalachians
D3 reaching as high as 30-50% for 0.1 inches in parts of PA/WV.


Weiss






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FOUS11 KWBC 280725
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
225 AM EST Sat Feb 28 2026

Valid 12Z Sat Feb 28 2026 - 12Z Tue Mar 03 2026


...Northern High Plains, Great Lakes, & Northeast...
Days 1-2...

A narrow but intense corridor of moderate to heavy snow will track
rapidly east-southeast from the Dakotas to the western Great Lakes
today. The heaviest snow late this morning will center from
southeastern North Dakota-northeastern South Dakota into southern
Minnesota, where strong low-mid-level frontogenesis and favorable
upper jet forcing will likely support a brief period of rates
exceeding 1"/hr. While this will be a fast-moving system, the
thermal profile remains cold throughout the column, supporting high snow-to-liquid ratios and a fluffy snow that will accumulate
quickly. WPC probabilities indicate that additional accumulations
(after 12Z) of 2-4" are likely from southeastern North Dakota-
northeastern South Dakota through southern Minnesota into southern
Wisconsin today. Embedded within this axis is an area of 30 percent probabilities for amounts over 4" centered over southern
Minnesota.

As the system moves across the Great Lakes on Sunday, forcing is
expected to weaken and the band is forecast to become disorganized,
with a diminishing threat for heavy accumulations downstream.


...Central Plains into the Mid-Atlantic...
Days 2-3...

The synoptic setup will be driven by a southern stream shortwave
trough ejecting from the Pacific, suppressing a downstream ridge
centered over the Southwest on Saturday before tracking into the
Central Plains on Sunday. This upper-feature will be guided by
northern stream jet streak, steering the energy toward the Mid-
Atlantic while simultaneously pushing a surface cold front south
into the Southern Plains and the Southeast. Amplifying low level
winds will tap Gulf moisture, supporting deepening moisture and a
broadening precipitation shield developing well north of the
boundary. A northward-surging warm nose will favor a transition to
a wintry mix along the northern edge of the precipitation shield
from eastern Nebraska-Kansas through the mid Mississippi into the
Ohio valleys Sunday into early Monday, while a persistent surface
high-pressure wedge will support a similar mix of precipitation
types over the central Appalachians into the Mid-Atlantic Monday
into early Tuesday.

For most of these areas, WPC probabilities for measurable ice
(0.01") max out in the 30-50 percent range. A notable exception
are the central Appalachians, where probabilities reach 70 percent
along the West Virginia Allegheny Mountains by early Tuesday, with
some 30 percent probabilities for accumulations over 0.10" there
as well. Probabilities suggest that snow accumulations will remain
an inch or less for most impacted areas. The latest run only shows parts
of northern Missouri and isolated parts of the West Virginia
mountains with probabilities greater than 50 percent for amounts
over an inch.

Pereira


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FOUS11 KWBC 281827
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
127 PM EST Sat Feb 28 2026

Valid 00Z Sun Mar 01 2026 - 00Z Wed Mar 04 2026


...Great Lakes, & Northeast...
Days 1-2...

The narrow but intense band of heavy snow across the Northern
Plains/Upper Midwest today will steadily weaken tonight as the
primary forcing moves eastward. This should result in an expansion
of the snow swath (more diffuse forcing leads to a broader
footprint with weaker intensity), but the driving shortwave aloft
interacting with the cold front will likely lead to weak surface
wave development tonight. This wave of low pressure moving across
the Ohio Valley and then into the Mid-Atlantic will lead to some
enhanced downstream warm advection to offset the loss of dynamics
from the west. This will allow snow to continue, and potentially
even expand its footprint from the Ohio Valley into New England.
Total snowfall is still expected to be modest thanks to the
transient nature of this event and the overall modest accompanying
ascent, but WPC probabilities indicate a low to moderate risk
(10-50% chance) of at least 2 inches of snow, highest across the
Adirondacks, Berkshires, and Green Mountains.


...Central Plains to the Tennessee Valley...
Days 2-3...

The overlap of a cold front sinking through the Central Plains and
into the Southeast with a modest shortwave emerging from the
Southwest will lead to expanding precipitation from the Central
Plains into the Mid-Atlantic states late Sunday through Monday.
This precipitation will generally be fueled by increasing southerly
flow out of the Gulf, with the associated WAA isentropically
ascending to drive precipitation while also pushing a warm nose
above 0C northward. This will result in an axis of snow, sleet,
freezing rain, and rain, with snow changing to mixed precip on the
north side of the precipitation shield as the warm nose progresses.

In general, the guidance has trended weaker with this event, but
any mixed precipitation can still cause travel issues. The highest
snow probabilities from WPC now only reach around 10% for 2+ inches
across MO. However, icing could be more substantial as reflected
by WPC probabilities that are widespread 50% for at least 0.01"
from KS through KY, with locally more than 0.1" possible (10-30%)
from southern IL into IN and KY.


...Mid-Atlantic to Northeast...
Day 3...

An amplifying mid-level trough ejecting out of the Great Basin will
track steadily eastward Monday night through Tuesday /D3/, reaching
the Central Plains by the end of the forecast period. A surface low
developing beneath this trough will track along a wavering warm front/stationary front draped eastward through the Mid-Atlantic. As
this low moves east in conjunction with its parent trough,
downstream height rises will occur through intensifying WAA, with
the resulting overrunning/upglide leading to an expansion of
precipitation from the Mid-Atlantic/Central Appalachians into the
Northeast/New England, especially as PWs surge to above the 90th
climatological percentile according to NAEFS. With Canadian high
pressure quickly retreating to the E/NE ahead of this system, the
warm nose accompanying the WAA will be unobstructed, and this will
likely result in a rapid transition from snow at precip onset, to a
mix of sleet/freezing rain, and eventually rain, even as far north
as southern New England. Before that transition, some impactful
winter weather is likely through briefly heavy snow (although
accumulations should be modest) and the icy sleet/freezing rain
combination which may lead to some modest ice accumulations in
higher elevations. WPC probabilities for snow indicate a moderate
risk (50-70%) of at least 2 inches of snow across the higher
elevations of Upstate NY, with lower probabilities extending into
central New England. For ice, there is a moderate risk (30-70%
chance) of at least 0.1" from the Central Appalachians into the
Laurel Highlands of PA, with locally as much as 0.25" possible.


...Central Rockies...
Day 3...

A potent shortwave ejecting out of the Pacific will translate
eastward into the Great Basin and then Four Corners states by
Tuesday morning. This feature will deepen into a closed low over
the Four Corners, helping to initiate cyclogenesis in the lee of
the Rockies as ascent becomes maximized in the LFQ of a subtropical
jet streak arcing towards the Central Plains. As this low
strengthens, increased moisture funneling northward from the Gulf
will track NW into CO/WY/UT as the accompanying theta-e ridge
rotates cyclonically around the low. This will create significant
snowfall accumulations, generally above 7000 ft, across the Uintas,
Tetons, Wind Rivers, and CO ROckies including the Park Range and
northern Front Range. In these areas, WPC probabilities of more
than 4 inches of snow reach 70-90%, with locally up to 10 inches
possible in isolated locations.


Weiss


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FOUS11 KWBC 010656
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
156 AM EST Sun Mar 1 2026

Valid 12Z Sun Mar 01 2026 - 12Z Wed Mar 04 2026


...Central Plains to the Tennessee Valley...
Days 1-2...

Migrating shortwave ejecting out of the Rockies through the Central
Plains to Ohio Valley will lead to a period of mixed precipitation
from KS/NE, east into the Ohio Valley. Initial wave of precip will
form across the Central Plains with a degradation of the lower
boundary layer over time as a marginal warm-nose protrudes the
layer between 925-700mb leading to a band of snow on the northern
periphery of the SLP center with more of a light sleet/freezing
rain signature along and north of I-70 from Northeast KS through
MO. Freezing rain accretion of 0.01-0.05" will be most common
across this area with WPC probs of >0.01" running between 30-60%
over the aforementioned corridor, but well below 10% for >0.1"
meaning limited chances for more considerable impacts.

Further east into the Ohio Valley, western edge of the strong
surface ridge pressing Arctic air into the region will lead to a
touch better isentropic ascent pattern as the slowly maturing SLP
migrating east will allow for a better 850mb jet nosing up into
the very cold boundary layer present across the OHV with the
southern fringes of freezing to sub-freezing air located along the
KY/TN border. Fairly high probs (40-70%) for at least 0.01" are
located across the northern half of KY with the best chance for
~0.05-0.1" located north of I-64. Snowfall of 1-2" are relatively
low across portions of OH/IN with probs for >1" only between 10-30%
over the central and southern portions of each state.

...Mid-Atlantic to Northeast...
Day 2-3...

There has been very little deviation in the forecasted pattern
expected with the next disturbance to impact the Mid-Atlantic and
Northeastern CONUS. An amplifying mid- level trough ejecting out
of the Great Basin will track steadily eastward Monday night
through Tuesday, leading to a surface low formation that will
track along a wavering warm front/stationary front draped eastward
through the Mid-Atlantic. As this low moves east in conjunction
with its parent trough, downstream height rises will occur through
intensifying WAA, with the resulting overrunning/upglide leading to
an expansion of precipitation from the Mid-Atlantic/Central
Appalachians into the Northeast/New England, especially as PWs
surge to above the 90th climatological percentile according to
NAEFS. With Canadian high pressure quickly retreating to the E/NE
ahead of this system, the warm nose accompanying the WAA will be
unobstructed, and this will likely result in a rapid transition
from snow at precip onset, to a mix of sleet/freezing rain, and
eventually rain, even as far north as southern New England. Before
that transition, some impactful winter weather is likely through
briefly heavy snow (although accumulations should be modest) and
the icy sleet/freezing rain combination which will lead to some
satisfactory ice accumulations in the higher elevations of the
Central Appalachians and neighboring valleys where CAD signatures
remain prevalent through Tuesday morning. WPC probabilities for
snow indicate a low-end risk (20-50%) of at least 2 inches of snow
across the higher elevations of the Adirondak's, Green and White
Mountains of VT/NH. For ice, there is a moderate risk (40-80%
chance) of at least 0.1" from the Central Appalachians into the
Laurel Highlands of PA, with locally as much as 0.25" possible.


...Central Rockies to Pacific Northwest...
Days 2-3...

A potent shortwave ejecting out of the Pacific will translate
eastward into the Great Basin and then Four Corners states by
Tuesday morning. This shortwave trough is forecast to close off
across the Inter-Mountain west between UT/CO, helping to initiate
cyclogenesis in the lee of the Rockies as ascent becomes maximized
in the LFQ of a subtropical jet streak arcing towards the Central
Plains. As this low strengthens, increased moisture funneling
northward from the Gulf will track NW into CO/WY/UT as the
accompanying theta-e ridge rotates cyclonically around the low.
This will create significant snowfall accumulations, generally
above 7000 ft, across the Uintas, Tetons, Wind Rivers, and CO
Rockies, including the Park Range and northern Front Range. In
these areas, WPC probabilities of more than 4 inches of snow reach
50-80%, with locally up to 10 inches possible in isolated
locations.

By D3, a second potent trough will enter the Pacific coast with
a solid mid-level moisture advection pattern into the Pacific
Northwest. This will allow for snowfall to occur across the
Northern Cascades with snow levels generally primed between
4000-4500ft AGL leading to mainly heavier snowfall totals above the
passes with the maxima focused >6500ft elevation. This will lead to
WPC probs of more than 60% for >4" focused within the higher
elevations of the Northern Cascades and Olympics.

Weiss/Kleebauer


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FOUS11 KWBC 011837
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
137 PM EST Sun Mar 1 2026

Valid 00Z Mon Mar 02 2026 - 00Z Thu Mar 05 2026

...Central Plains to Tennessee Valley...
Day 1...

Weak shortwave traversing through generally zonal flow from the
Central Plains to the Southern Appalachians will create a period of
modest ascent across the region. Subtle height falls along the
low-level baroclinic gradient associated with a stalled cold front
will help develop a wave of low pressure, and as this low pressure
tracks eastward along the front it will enhance a swath of
precipitation around it. Despite the weak nature of this surface
low, downstream warm and moist advection will intensify on 850mb
winds surging out of the Gulf, transporting moisture and a warm
nose northward, with increasing isentropic upglide leading to an
expansion of precipitation. The column is marginally supportive of
winter p-types, so while some areas will begin as snow, especially
from northern MO through southern OH, the advance of the warm nose
will result in mostly rain or freezing rain as the system
translates eastward through Monday afternoon. Total snowfall is
expected to be minimal at less than 2". However, WPC probabilities
indicate a 50-70% chance of at least 0.01" of ice, with some
locally higher totals approaching 0.1" for NW MO and north-central
KY/southern IN as reflected by significant spread in the WSE plumes
across these areas.


...Mid-Atlantic to Northeast...
Day 2-3...

An amplifying mid-level trough ejecting out of the Great Basin
will track steadily eastward Monday night through Tuesday, leading
to a surface low formation that will track along a wavering warm front/stationary front draped eastward through the Mid-Atlantic. As
this low moves east in conjunction with its parent trough,
downstream height rises will occur through intensifying WAA, with
the resulting overrunning/upglide leading to an expansion of
precipitation from the Mid-Atlantic/Central Appalachians into the
Northeast/New England, especially as PWs surge to above the 90th
climatological percentile according to NAEFS. With Canadian high
pressure quickly retreating to the E/NE ahead of this system, the
warm nose accompanying the WAA will be able to surge quickly
northeast, and this will likely result in a rapid transition from
snow at precip onset, to a mix of sleet/freezing rain, and
eventually rain, even as far north as southern New England. Before
that transition, some impactful winter weather is likely through
briefly heavy snow (although accumulations should be modest) and
the icy sleet/freezing rain combination which will lead to some
impactful ice accumulations in the higher elevations of the
Central Appalachians and neighboring valleys where CAD signatures
remain prevalent through Tuesday morning.

WPC probabilities for snow exceeding 2" each day exceed 30% only in
a few isolated areas, the higher Central Appalachians D1, the
Greens and Berkshires on D2, and coastal/Downeast Maine on D3.
Total snowfall may reach 4" in a few of these areas.

The icing is expected to be more impactful, especially in the
Central Appalachians, where the probability for at least 0.1" of
ice exceeds 50-70% in the higher elevations of the Alleghenies, the
Blue Ridge of VA, and into the Laurel Highlands of PA. Locally as
much as 0.25" is possible in isolated locations. More widespread
icing exceeding 0.01" is expected from far NW NC through southern
New England, including the I-95 corridor from Washington, D.C.
through New York City where the Tuesday commutes could be impacted
by light icing and mixed precipitation.


...Central Rockies...
Days 1-2...

A potent closed low emerging from the Pacific will cross onshore CA
late tonight and then continue eastward across the Great Basin and
into the Central Rockies by Tuesday morning. Although this feature
is now progged to weaken as it translates eastward, it will still
maintain sufficient amplitude to drive robust height falls/PVA into
the Central Rockies, which when combined with a modest (80-90kts)
jet streak placed favorably into the Central Plains, will result in
lee cyclogenesis Monday evening. This low will deepen at least
marginally as it advects E/SE into Tuesday, while downstream moisture
from the Gulf gets wrapped cyclonically into the system to create
anomalous PWs as high as the 97th climatological percentile. The
combination of synoptic ascent with upslope enhancement
north/northwest of the surface low will create areas of heavy snow,
especially above 7000 ft in the Uintas, Tetons, Wind Rivers,
Laramie Range, and across much of the CO Rockies including the Park
and Front Ranges. In these areas, WPC probabilities are high (>70%)
for at least 4" D1 in NW WY, expanding to include the terrain of
UT and CO on D2. Locally as much as 10" of snow is possible in the
higher terrain.


...Pacific Northwest...
Day 3...

An amplifying shortwave trough positioned well of the Pacific
Northwest coast will gradually advect eastward, coming onshore
Wednesday morning. As this shortwave moves onshore, it will produce
impressive height falls which will overlap with the RRQ of a
meridionally strengthening jet streak (downstream of the primary
trough axis) to drive pronounced deep layer lift into the
Northwest. At the same time, confluent flow immediately ahead of
the mid-level trough will gradually back to be more SW, pumping
elevated IVT onshore to provide the moisture needed for heavy
precipitation. There remain considerable differences among the
various models as to the intensity of this IVT, with the ECENS
suggesting a higher than 80% chance of at least 250 kg/m/s, which
is close to the West-WRF probabilities, while the GEFS shows almost
no IVT at all. Hedging towards the more aggressive guidance
indicates that this should result in periods of heavy snow,
especially in the Olympics, Cascades, and Northern Rockies, with
snow levels falling steadily from around 5000 ft to 4000 ft
beneath the upper trough and a corresponding cold front. WPC
probabilities D3 are high (>70%) for at least 4" of snow along the
spine of the Cascades of OR and WA, the highest terrain of the
Olympics, and parts of OR/ID/MT from the Blue Mountains through the
Sawtooth Region and into the far Northern Rockies near Glacier NP.


Weiss


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FOUS11 KWBC 020703
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
203 AM EST Mon Mar 2 2026

Valid 12Z Mon Mar 02 2026 - 12Z Thu Mar 05 2026

...Ohio and Tennessee Valley's...
Day 1...

Weak shortwave traversing through generally zonal flow from the
Central Plains to the Southern Appalachians will create a period of
modest ascent across the region. Current WV satellite and radar
composite shows the disturbance situated over the mid-Mississippi
Valley this evening moving due east with sights generally along the
central Ohio River Valley. Low-level baroclinicity along a cold
front stalled across the Lower Tennessee Valley will allow for
maintenance of surface low pressure in conjunction with the mid-
level shortwave, tracking eastward along the front allowing for an
enhancement of precipitation in the confines of the Ohio and
Tennessee Valley's, respectively. Despite the weak nature of this
surface low, downstream warm and moist advection will intensify on
850mb winds surging out of the Gulf, transporting moisture and a
warm nose northward, with increasing isentropic upglide leading to
an expansion of precipitation from the Mississippi River to points
east with the northern periphery of the precip field delegated to
the expected winter p-types. The column will remain marginally
supportive of winter weather, however, thanks to the warm nose
protruding the lower confines of the boundary layer meaning the
swath of snow or freezing rain will be relatively narrow,
especially south-central IL through southern OH. Total snowfall is
expected to be minimal at less than 2". However, WPC probabilities
indicate a 50-90% chance of at least 0.01" of ice, with some
locally higher totals approaching 0.1" for southern Ohio around the
proximity of Cincinnati and points north away from the immediate
Ohio River basin as noted via lower probs (10-25%) for the 0.1"
threshold.


...Mid-Atlantic to Northeast...
Day 1-2...

Mid-level trough over the mid-Mississippi Valley will advance
downstream into the Ohio Valley with an attendant surface low
migrating east along a stalled frontal boundary located over the
Lower Tennessee Valley as of early this morning. As this low moves
east in conjunction with its parent trough, downstream height
rises will occur through intensifying WAA, with the resulting overrunning/upglide leading to an expansion of precipitation from
the Mid-Atlantic/Central Appalachians into the Northeast/New
England, especially as PWs surge to above the 90th climatological
percentile according to NAEFS. With Canadian high pressure quickly
retreating to the E/NE ahead of this system, the warm nose
accompanying the WAA will be able to surge quickly northeast, and
this will likely result in a rapid transition from snow at precip
onset, to a mix of sleet/freezing rain, and eventually rain, even
as far north as southern New England. Before that transition, some
impactful winter weather is likely through briefly heavy snow
(although accumulations should be modest) and the icy
sleet/freezing rain combination which will lead to some impactful
ice accumulations in the higher elevations of the Central
Appalachians and neighboring valleys where CAD signatures remain
prevalent through Tuesday morning.

WPC probabilities for snow exceeding 2" each day exceed 30% only in
a few isolated areas, the higher Central Appalachians D1, the
Greens and Berkshires on D2, and coastal/Downeast Maine on D2-2.5.
Total snowfall may reach 4" in a few of these areas, mainly in
elevations above 4000ft MSL.

The icing is expected to be more impactful, especially in the
Central Appalachians, where the probability for at least 0.1" of
ice exceeds 50-90% in the higher elevations of the Alleghenies,
the Blue Ridge of VA, and into the Laurel Highlands of PA. Latest
probs for >= 0.25" have come up towards 30-50% within a narrow
corridor along the spine of the Central Appalachians of east-
central WV, mainly as you move south of the Canaan Valley along the
eastern Continental Divide. More widespread icing exceeding 0.01"
is expected from far NW NC through southern New England, including
the I-95 corridor from Washington, D.C. through New York City where
the Tuesday commutes could be impacted by light icing and mixed
precipitation. Highest probabilities for >0.01" of ice accretion
will be found generally northwest of the fall line, especially as
you west of the Blue Ridge and Susquehanna Valley in PA.


...Central Rockies...
Days 1-2...

A potent closed low emerging from the Pacific has begun to push
ashore this evening over Northern California with an expectation
of continuing eastward across the Great Basin today, eventually
ejecting into the Central Rockies by Tuesday morning. Although
this feature is now progged to weaken as it translates eastward, it
will still maintain sufficient amplitude to drive robust height
falls/PVA into the Central Rockies, which when combined with a
modest (90-100kt) jet streak placed favorably into the Central
Plains, will result in lee cyclogenesis Monday evening. This low
will deepen at least marginally as it advects E/SE into Tuesday,
while downstream moisture from the Gulf gets wrapped cyclonically
into the system to create anomalous PWs as high as the 97th
climatological percentile. The combination of synoptic ascent with
upslope enhancement north/northwest of the surface low will create
areas of heavy snow, especially above 7000 ft in the Uintas,
Tetons, Wind Rivers, Laramie Range, and across much of the CO
Rockies including the Park and Front Ranges. In these areas, WPC
probabilities are high (50-80%) for at least 4" D1 in NW WY,
expanding to include the terrain of UT and CO on D2. Locally as
much as 10" of snow is possible in the higher terrain.


...Pacific Northwest...
Day 2-3...

An amplifying shortwave trough currently positioned over the Gulf
of Alaska will gradually advect southeastward, coming onshore
Wednesday morning. As this shortwave moves onshore, it will produce
impressive height falls which will overlap with the RRQ of a
meridionally strengthening jet streak (downstream of the primary
trough axis) to drive pronounced deep layer lift into the
Northwestern CONUS. At the same time, confluent flow immediately
ahead of the mid-level trough will gradually back to be more SW,
pumping elevated IVT onshore to provide the moisture needed for
heavy precipitation. Global deterministic and their ensembles are
starting to converge on a relatively modest IVt advection regime
~250 kg/ms, aligning with the ECENS outputs that have been
consistent within this range for the past few days. This scenario
should result in periods of heavy snow, especially in the
Olympics, Cascades, and Northern Rockies, with snow levels falling
steadily from around 5000 ft to 4000 ft beneath the upper trough
and a corresponding cold front. WPC probabilities D3 are high

70%) for at least 4" of snow along the spine of the Cascades of

OR and WA, the highest terrain of the Olympics, and parts of
OR/ID/MT from the Blue Mountains through the Sawtooth Region and
into the far Northern Rockies near Glacier NP.

Weiss/Kleebauer





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FOUS11 KWBC 021848
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
148 PM EST Mon Mar 2 2026

Valid 00Z Tue Mar 03 2026 - 00Z Fri Mar 06 2026

...Mid-Atlantic to the Northeast...
Days 1-2...

Broad westerly flow aloft has brought moisture to the East, and
retreating high pressure over New England was able to slip colder
air southward east of the Appalachians, setting up a wintry mix for
locations overnight. A wavy frontal boundary over the TN Valley
into the Southeast will eventually lift northward/northeastward
tomorrow as a weak area of low pressure off the NC Coast also moves
northward. In the intervening hours, sub-freezing surface
temperatures beneath warming lower-level temperatures favors
freezing rain over the central Appalachians toward the I-95
corridor tonight and snow to the north where the cold air is
deeper. The precipitation shield will advance northward tomorrow
along with the ptype transition zone. Some mixing will occur as far
north as central New England into the southern Adirondacks. Low
pressure will eventually carry the system off the coast by early
Wednesday.

Snow amounts will generally be light, especially in the Mid-
Atlantic. From around I-90 northward, WPC probabilities for at
least 4 inches of snow are low (10-40%) as most amounts should be
in the 1-3" range. Higher elevations of the Green and White
mountains show the highest chance for at least 4 inches of snow.
The freezing rain footprint will extend from southern WV and
southwestern VA northward along the I-81 corridor and as far west
as the I-79 corridor northward to about I-90 and eastward to about
I-95. Freezing rain accumulations will be highest where the cold
air holds on longest near the highest QPF, which is forecast to be
over the central Appalachians (eastern WV and western VA into PA in
the typically favored locations). WPC probabilities for at least
0.10" icing are >50% over many of these generally elevated areas,
with some areas of eastern WV receiving around/over 0.25" ice.


...Central Rockies...
Day 1...

A closed low over the Great Basin this afternoon will move through
the Central Rockies tonight/Tuesday and onto the Plains by early
Wednesday. Combination of height falls/PVA and a modest (90-100kt)
jet streak will along with upslope enhancement north/northwest of
the surface low will create areas of heavy snow, especially above
7000 ft in the Uintas, Tetons, Wind Rivers, Laramie Range, and
across much of the CO Rockies including the Park and Front Ranges.
The system will be progressive and snow should exit the region late
tomorrow night. WPC probabilities for at least 6 inches of snow
are >50% above about 8000ft or so.


...Pacific Northwest, Great Basin, and Northern Rockies...
Days 2-3...

A deepening system in the Gulf of Alaska will move southeastward
tomorrow, bringing a surge of moisture into the Pacific Northwest
ahead of a cold front. Moisture levels and IVT anomalies will be
modest, and snow levels will start around 5000-6000ft before
falling post-FROPA to around 4000ft Wednesday then to near 3000ft
Thursday as precipitation becomes much lighter. Snow will spread
eastward to the Northern Rockies (northern ID to northwestern MT)
early Wednesday then to the Great Basin late Wednesday into
Thursday as the upper trough moves into southwestern OR. Snow could
be heavy at times near/above pass level as snow levels fall across
the Cascades tomorrow night. By the end of the forecast period,
the upper trough may deepen into a closed low over southwestern UT
with snow spreading into the Uintas and Wasatch as well as western
WY ranges, continuing into the medium range.

WPC probabilities for at least 8 inches of snow are highest over
the WA/OR Cascades, generally above 4000-5000ft. Plowable snow (at
least a couple inches) is likely (>80% chance) around Snoqualmie
Pass. To the east, WPC probabilities for at least 8 inches of snow
are >50% above 5000-6000ft or so over the Blue Mountains, central
ID ranges, western MT, and northern NV.


Fracasso


$$

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FOUS11 KWBC 030719
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
219 AM EST Tue Mar 3 2026

Valid 12Z Tue Mar 03 2026 - 12Z Fri Mar 06 2026

...Mid-Atlantic to the Northeast...
Days 1 & 3...

The general synoptic pattern is unchanged from the previous
forecast. Weak shortwave trajectory from the Mid Atlantic will
motion northeastward off the the coast of Southern New England
with moisture carried poleward in the process. 1041mb surface
ridge positioned off Cape Cod will lead to a shift in the low-level
flow by morning to a more easterly orientation with a nosing low-
level jet around 850mb allowing a warm air protrusion into the
boundary layer as we push through D1. Cold air will slowly retreat
northward with snow/ice across the Northeast changing to rain, even
as far north as Southern New England. Areas north of I-90 will hold
on to cold air the longest with snow/ice the primary p-types
through the event. Best ascent will be fixed to the southeast,
however, so totals for freezing rain and snow will be relatively
modest, at best leading to some minor to bordering moderate impacts
where ice accretion approaches 0.1" or greater. Low pressure will
eventually carry the system off the coast by early Wednesday
leading to an end of the impact from this disturbance.

Snow amounts will generally be light, especially in the Northern Mid-
Atlantic. From around I-90 northward, WPC probabilities for at
least 4 inches of snow are low (10-40%) as most amounts should be
in the 1-3" range. Higher elevations of the Green and White
mountains show the highest chance for at least 4 inches of snow.
The freezing rain footprint will extend from the WV Panhandle into
the Allegheny front, northward along the I-81 corridor and as far
west as the I-79 corridor northward to about I-90 and eastward to
about I-95. Freezing rain accumulations will be highest where the
cold air holds on longest near the highest QPF, which is forecast
to be over the central Appalachians and highlands of west-central
PA. WPC probabilities for at least 0.10" icing are between 30-60% over west-central PA up towards the NY state line with lower probs <20%
for parts of the Catskills and Berkshires.

By D3, a potent mid-level shortwave will eject east-northeast out
of the Midwest, aiming sights at Upstate NY through New England by
the end of the period. A trailing axis of confluence over Atlantic
Canada with a strong 1038+ mb surface ridge migrating east out of
Central Canada will set the stage for a stout low-level CAD
signature within the valley's of New England leading to a
heightened threat for freezing rain as the boundary layer between
925-700mb will be too warm, promoting liquid hydrometeors. Shallow
but impressive CAD will lead to a transient light to moderate
freezing rain between 00-12z Friday with WPC probabilities for

0.1" already signaling 10-40% potential across the

Hudson/Champlain Valley's along the NY/VT border, as well as
through the southern Green mountains and neighboring Berkshires.


...Central Rockies...
Day 1...

Current WV satellite and UA analysis shows a very distinct closed
upper reflection located over the southern reaches of the Tetons
with snowfall occurring over the Wasatch over into the WY ranges
and the northwestern portion of CO. This threat will carry through
the morning with snowfall likely to breach 4" across portions of
the Central Rockies including the Medicine Bow range located over
northern CO and southern WY. Probs continue to come in between
40-70% for those areas of additional snowfall >4" leading to totals
likely to push 10+" through the storms life cycle. System will
exit the second half of the forecast leading to an end to the
threat as we move into the evening hours.


...Pacific Northwest, Great Basin, and Northern Rockies...
Days 2-3...

A deepening system in the Gulf of Alaska will move southeastward
through today, bringing a surge of moisture into the Pacific
Northwest ahead of a cold front. Moisture levels and IVT anomalies
will be modest, and snow levels will start around 5000-6000ft
before falling post- FROPA to around 4000ft Wednesday then to near
3000ft Thursday as precipitation becomes much lighter. Snow will
spread eastward to the Northern Rockies (northern ID to
northwestern MT) early Wednesday then to the Great Basin late
Wednesday into Thursday as the upper trough moves into southwestern
OR. Snow could be heavy at times near/above pass level as snow
levels fall across the Cascades tomorrow night. By the end of the
forecast period, the upper trough may deepen into a closed low over southwestern UT with snow spreading into the Uintas and Wasatch as
well as western WY ranges, continuing into the medium range.

WPC probabilities for at least 8 inches of snow are highest over
the WA/OR Cascades for D2, generally above 4000-5000ft. Plowable
snow (at least a couple inches) is likely (>80% chance) around
Snoqualmie Pass. To the east, WPC probabilities for at least 8
inches of snow are >50% above 5000-6000ft or so over the Blue
Mountains, central ID ranges, western MT, UT mountains, and
northern NV.

Fracasso/Kleebauer


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FOUS11 KWBC 031906
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
206 PM EST Tue Mar 3 2026

Valid 00Z Wed Mar 04 2026 - 00Z Sat Mar 07 2026

...Northeast...
Day 1...

Weak area of low pressure near coastal Southern New England this
evening will continue to strengthen just a bit as it lifts
northeastward into the Gulf of Maine around midnight then into Nova
Scotia Wednesday morning. Cold air (and sub-32F dew points) remain
over Maine with a transition to marginal temperatures into central
and southern areas of New England and eastern NYS. This will favor
a continuation of snow/sleet/freezing rain over the region this
evening before precipitation ends around 12Z Wed. Snow amounts will
generally be light (1-3") except for some enhancement around the
Green and White Mountains where WPC probabilities for at least 4
inches of snow are low (10%). Icing amounts of at least 0.01" are
focused over the Catskills, Berkshires, and Worcester Hills where
an additional 0.10" of ice is possible after 00Z (10-30% chance).

Day 3...

By day 3, a potent mid-level shortwave (currently over the
Rockies) will eject east-northeast out of the Midwest and weaken as
it rides the quasi-zonal flow into the Northeast. A trailing axis
of confluence over Atlantic Canada with a strong 1038+ mb surface
ridge migrating east out of Central Canada will set the stage for a
mixed ptype event as cold air remains entrenched over areas along
and north of I-90. Cold air damming, aided by a cold front from the
Great Lakes to Nova Scotia, will favor freezing rain as the
precipitation mode though some light snow is possible over New
Hampshire into southwestern Maine which will be fully into the cold
air. Precipitation starting Thursday evening will continue through
Friday and taper off by the end of this forecast period (00Z Sat)
as the shortwave moves into the Atlantic. WPC probabilities for at
least 0.10 inch icing are moderate (40-70%) over the southern Green
Mountains and Berkshires as well as across southern New Hampshire
(Monadnocks) into the Worcester Hills. Lighter icing (>0.01") is
probable for much of the Adirondacks and Catskills across Vermont
and New Hampshire into northern CT/RI.


...Central Rockies...
Day 1...

Exiting mid-level system over CO this evening will pull away from
the region overnight. Additional snow accumulations should be light
(1-2") with some 3-4" amounts possible over 10,000ft.


...Pacific Northwest, Great Basin, and Rockies...
Days 1-3...

A mature system in the Gulf of Alaska will weaken as it moves into
British Columbia this evening, but its southern mid-level trough
will continue into the Pac NW, carrying a cold front ashore. A
surge of modest moisture and IVT, coupled with snow levels
initially around 5000-6000ft, will limit impacts. However, post-
FROPA, snow levels will fall to around 4000ft Wednesday then to
near 3000ft Thursday as precipitation becomes much lighter. Snow
will spread eastward to the Northern Rockies (northern ID to
northwestern MT) early Wednesday then to the Great Basin late
Wednesday into Thursday as the upper trough moves into southwestern
OR. Snow could be heavy at times near/above pass level as snow
levels fall across the Cascades tonight and then again tomorrow
evening as the upper trough moves through WA/OR. On Thursday, the
trough will dig into Utah which will enhance snowfall into the
Uintas, WY ranges, and into the CO Rockies. Snow levels will
continue to fall across the region, initially around 7000ft in
WY/CO late Thursday but dropping to below 5000ft early Friday,
bringing some lighter snow to areas east of the Front Range.

WPC probabilities for at least 8 inches of snow are >50% over the
WA/OR Cascades, generally above 4000-5000ft. Plowable snow (at
least a few inches) is likely (>90% chance) around Snoqualmie Pass.
To the east, WPC probabilities days 2-3 for at least 8 inches of
snow are >50% above 5000-6000ft or so over the Blue Mountains,
central ID ranges, western/southwestern MT, northern NV ranges,
Uintas/Wasatch, and into the Wind River, Laramie, Park Range, and
Medicine Bow ranges.


Fracasso



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FOUS11 KWBC 040749
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
249 AM EST Wed Mar 4 2026

Valid 12Z Wed Mar 04 2026 - 12Z Sat Mar 07 2026

...Northeast...
Day 2...

A potent mid-level shortwave (currently over the Rockies) will
eject east-northeast out of the Midwest and weaken as it rides the
quasi-zonal flow into the Northeast. A trailing axis of confluence
over Atlantic Canada with a strong 1038+ mb surface ridge migrating
east out of Central Canada will set the stage for a mixed ptype
event as cold air remains entrenched over areas along and north of
I-90. Cold air damming, aided by a cold front from the Great Lakes
to Nova Scotia, will favor freezing rain as the precipitation mode
though some light snow is possible over New Hampshire into
southwestern Maine, which will be fully into the colder airmass.
Precipitation starting Thursday evening will continue through
Friday as the shortwave and associated weak area of surface low
pressure races eastward into the Atlantic. WPC probabilities for
at least 0.10 inch icing are moderate (40-70%) over the southern
Green Mountains and Berkshires as well as across southern New
Hampshire (Monadnocks) into the Worcester Hills. Probabilities for
at least 0.25 inch icing is highest (20-40%) over the southern
Greens and Berkshires. Lighter icing (>0.01") is probable for much
of the Adirondacks and Catskills across Vermont and New Hampshire
into northern CT/RI.


...Pacific Northwest, Great Basin, and Rockies...
Days 1-3...

A mature system in the Gulf of Alaska weakening early this morning
will shunt a southern mid- level trough into the Pac NW today,
carrying a potent cold front ashore. A surge of modest moisture
and IVT, coupled with snow levels initially around 5000-6000ft,
will limit impacts. However, post- FROPA, snow levels will fall to
around 4000ft today then to near 3000ft Thursday as precipitation
becomes much lighter. Snow will spread eastward to the Northern
Rockies (northern ID to northwestern MT) early this morning then
to the Great Basin late this afternoon into Thursday as the upper
trough moves into southwestern OR. Snow could be heavy at times
near/above pass level as snow levels fall across the Cascades
today and then again tomorrow evening as the upper trough moves
through WA/OR. On Thursday, the trough will dig into Utah which
will enhance snowfall into the Uintas, WY ranges, and into the CO
Rockies, favoring upslope regions with ranges oriented
perpendicular to the northwesterly flow. Snow levels will continue
to fall across the region, initially around 7000ft in WY/CO late
Thursday but dropping to below 5000ft early Friday. This may
bring some lighter snow to areas east of the Front Range and High
Plains, including from eastern CO and southeast WY to western NE
and central SD.

WPC days 1-2 probabilities for at least 8 inches of snow are >50%
over the WA/OR Cascades, generally above 4000-5000ft. Plowable snow
(at least a few inches) is likely (>95% chance) around Snoqualmie
Pass. To the east, WPC probabilities through day 3 for at least 8
inches of snow are >50% above 5000-6000ft or so over the Blue
Mountains, central ID ranges, western/southwestern MT, northern NV
ranges, Uintas/Wasatch, and into the Wind River, Laramie, Park
Range, and Medicine Bow ranges. Maximum snowfall amounts of 1 to 2
feet can be expected in the highest peaks of these mountain ranges.


...Central/Northern Plains and Upper Midwest...
Day 3...

More uncertainty regarding QPF and ptype exists throughout
the central/northern Plains and Upper Midwest on day 3 (12z Fri.
to 12z Sat.) as this system ejects eastward. Although less likely
at the moment, should a stronger shortwave eject northeastward
across the Plains on Friday and spawn a deeper surface low along
the advancing cold front, a band of heavy snow is possible.
However, the GFS remains alone in this higher end scenario.
Current WPC probabilities for at least 2 inches of snow are low
(20-40%) from western NE to northern MN.


Snell/Fracasso




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FOUS11 KWBC 041839
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
139 PM EST Wed Mar 4 2026

Valid 00Z Thu Mar 05 2026 - 00Z Sun Mar 08 2026

...Northeast...
Day 2...

A weakening mid-level shortwave over the central Plains will
continue eastward as it rides the quasi-zonal flow into the
Northeast by early Friday. A cold front will slip southward into
New England tomorrow with a strong 1038+ mb surface high in its
wake, anchoring in cold surface temperatures for at least central
and northern New England. This will set the stage for a mixed ptype
event focused over areas along and north of I-90 with at least
some icing likely north and south of this region. Freezing rain
will be the precipitation mode overall, though some light snow
(1-3") is likely over Vermont/New Hampshire into southwestern
Maine, which will be fully into the colder airmass. Precipitation
starting Thursday evening will continue through Friday as the
shortwave and associated weak area of surface low pressure races
eastward into the Atlantic. Precipitation should end from west to
east Friday afternoon. WPC probabilities for at least 0.10 inch
icing are >50% over the southern Adirondacks, southern Green
Mountains and Berkshires, as well as across the Worcester Hills.
Probabilities for at least 0.25 inch icing are highest (30-60%)
over the Berkshires and Worcester Hills. Lighter icing (>0.01") is
probable for much of the Adirondacks and Catskills across Vermont
and New Hampshire into northern CT/RI.


...Pacific Northwest, Great Basin, and Rockies...
Days 1-3...

A potent cold front has moved ashore with a surge of modest
moisture and IVT across the Great Basin/Rockies and lowering snow
levels in its wake. Impacts over the Cascades will increase to
lower elevations as snow levels fall to near 3000ft
overnight/Thursday as precipitation becomes much lighter. This will
impact many of the passes, including Snoqualmie, where the
probability of at least a few inches is >90%. Snow will continue to
spread through the Rockies and Great Basin overnight as the upper
trough reaches the NV/UT border early Thursday. Tomorrow, the
trough will dig into Utah which will enhance snowfall into the
Uintas, WY ranges, and into the CO Rockies, favoring upslope
regions with ranges oriented perpendicular to the northwesterly
flow. Additional snow is likely to the north over MT where 1-2"/hr
rates are possible tomorrow. Snow levels will continue to fall
across the region, initially around 7000ft in WY/CO late Thursday
but dropping to below 5000ft early Friday. This may bring some
lighter snow to valley locations in the interior Rockies as well as
areas east of the Front Range and to the High Plains (including
from eastern CO and southeast WY to western NE and central SD).

WPC days 1-2 probabilities for at least 8 inches of snow are >50%
over the WA/OR Cascades, generally above 4000-5000ft. To the east,
WPC probabilities through day 3 for at least 8 inches of snow are

50% above 5000-6000ft or so over the Blue Mountains, central ID

ranges, western/southwestern MT, northeastern NV ranges,
Uintas/Wasatch, and into the Wind River, Laramie, Park Range, and
Medicine Bow ranges. Maximum snowfall amounts of 1 to 2 feet can be
expected in the highest peaks of these mountain ranges. Lower
elevation/valley snow amounts will generally be in the T-2" range,
including Salt Lake City, Moab, and Grand Junction, though Denver
may see >1" (50% chance).


...Central/Northern Plains and Upper Midwest...
Day 3...

The trough will eject in multiple parts onto the Northern Plains
Friday into Saturday, with marginal temperatures beneath the area
of precipitation on the northwest side of low pressure moving into
the Corn Belt. Uncertainty remains high in QPF amounts, placement,
and ptype, though the potential exists for a band of at least
modest snow from central SD northeastward to northern MN. For now,
WPC probabilities for at least 4 inches of snow are no higher than
about 10% and are only 10-25% for at least 2 inches of snow.


Fracasso/Snell


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FOUS11 KWBC 050857
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
357 AM EST Thu Mar 5 2026

Valid 12Z Thu Mar 05 2026 - 12Z Sun Mar 08 2026

...Northeast...
Days 1/2...

Shortwave low over IA early this morning will further weaken into a
trough as it shifts to the eastern Great Lakes today and over
central New England tonight. A 1040mb high over Quebec retains a
wedge of cold air over New England through the Hudson Valley. Warm
air advection ahead of the low overruns the cold setting up mixed
precip and some all snow well into the cold sector. Snow probs are
quite limited, generally around 20% for >2" over southern NH and
far southern Maine which depends on how far precip can shift into
the dry high. Otherwise, it's ice glaze potential from the
Catskills, Berkshires into the Litchfield Hills and over the
Worcester Hills where Day 1 probs for >0.25" are 20-60%. Plenty of
precip occurs with this system, so it will come down to surface
temperatures and efficiency of freezing rain with rate and wind
factoring in. As of now the potential for 0.5" ice is limited to
the Berkshires where the PWPF is around 10%.


...Cascades through the Rockies...
Days 1-2...

A trough over Nevada this morning will dig down to AZ today and
promote lee-side sfc cyclogenesis over eastern CO tonight. In the
meantime, broad upper troughing over the northeast Pacific with low
pressure over central AK will direct a plume of Pacific moisture
across the NW on northwesterly flow.

Areas east of the trough axis will see moderate precip rates today with
lower snow levels around 4000ft over the UT/eastern ID ranges up
through western MT and western WY ranges. Onshore flow and snow
levels around 3500ft brings snow to the WA Cascades today. Day 1
PWPF >6" are 50-90% in southwest MT ranges and 40-80% from
northwest MT through the UT Ranges and up through the Bighorns in
WY.

The central Rockies get the focus late tonight through Friday with
the lee-side low bringing some Pacific and west Gulf moisture back
over the CO Rockies. Day 2 PWPF for >6" are 40-80% over most of the
CO and southern WY Rockies which will be quite welcome. The snow
focus shifts to the Plains by late Friday night.


...Central/Northern Plains and Upper Midwest...
Days 2/3...

A trough over Nevada this morning will dig down to AZ today,
promote lee-side sfc cyclogenesis over eastern CO tonight that
tracks over Iowa and Wisconsin Friday and northern Michigan early
Saturday. The strength of this low is the main point of uncertainty
with deeper solutions from the GFS and AiGFS (and now somewhat the
00Z CMC) develop a TROWAL band from western Nebraska through MN
while weaker solutions like the EC have only minor fgen banding on
the back side. WPC QPF favors decent fgen banding which would set
up some overrunning and a swath of wintry mix along with snow
banding. Day 2 PWPF for >4" are limited by the model variance with 20%
in western Neb and 5% in central SD. However, probs for >2" are 10%
or higher from western Neb through northern MN. Given the banding
potential and motion along banding orientation, some heavy snow is
possible in narrow swaths west of the low track.


Jackson


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FOUS11 KWBC 051905
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
205 PM EST Thu Mar 5 2026

Valid 00Z Fri Mar 06 2026 - 00Z Mon Mar 09 2026

...Northeast...
Days 1/2...

Shortwave low over IA early this morning will further weaken into
a trough as it shifts to the eastern Great Lakes today and over
central New England tonight. A 1040mb high over Quebec retains a
wedge of cold air over New England through the Hudson Valley. Warm
air advection ahead of the low overruns the cold setting up mixed
precip and some all snow well into the cold sector. Snow probs are
quite limited, generally around 20% for >2" over southern NH and
far southern Maine which depends on how far precip can shift into
the dry high. Otherwise, it's ice glaze potential from the
Catskills, Berkshires into the Litchfield Hills and over the
Worcester Hills where Day 1 probs for >0.25" are 20-60%. Plenty of
precip occurs with this system, so it will come down to surface
temperatures and efficiency of freezing rain with rate and wind
factoring in. As of now the potential for 0.5" ice is limited to
the Berkshires where the PWPF is around 10%.


...Cascades through the Rockies...
Days 1-3...

A digging trough over Utah this evening will dig down to AZ
tonight and promote lee-side sfc cyclogenesis over eastern CO
tonight (see next section for that portion of the system).
Concurrently, building ridging in the northeast Pacific will favor northwesterly flow into the Pac NW which will continue some light
to modest snow for the Cascades eastward to ID and western MT which
will continue in waves through Sunday. WPC probabilities for at
least 8 inches of snow are >50% above about 5000ft over the
Cascades to the central ID ranges and western/southwestern Montana.

The upper trough will focus some locally heavier snow (1-2"/hr
rates) over the Uintas into Colorado as the low moves eastward
directly over central CO before weakening and stretching
northeastward over the Plains tomorrow evening. WPC probabilities
for at least 8 inches of snow are >50% above about 8000-9000ft. The
highest totals >12-18 inches are likely in the San Juans and at
elevations > 10,000ft.


...Central/Northern Plains and Upper Midwest...
Days 1-2...

Continuation of the upper trough/low over the Rockies will promote
lee-side sfc cyclogenesis over eastern CO tonight that tracks over
Iowa and Wisconsin Friday and northern Michigan early Saturday.
Guidance remains uncertain in the strength of this low (e.g., GFS
stronger and farther northwest) and any potential TROWAL
development contingent upon said strengthening. Middle ground
approach, for now, yields generally light snow for the Northern
Plains to the Upper Midwest but likely with an area of higher
totals via banding and enhanced FGEN in the region despite the
marginal temperatures. Individual 12Z CAM guidance shows some
spotty 4-6" amounts between northern NE through SD to northern MN
but others show next to nothing. WPC probabilities for at least 4
inches of snow remain low (10% or less) but the area bears
watching.


Mullinax/Fracasso



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FOUS11 KWBC 060905
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
405 AM EST Fri Mar 6 2026

Valid 12Z Fri Mar 06 2026 - 12Z Mon Mar 09 2026


...Rockies, Central/Northern Plains and Upper Midwest...
Days 1-2...

Full-latitude trough with the axis approaching the Four Corners
early this morning will continue to promote lee-side cyclogenesis
from the southern High Plains up through western/central KS and
eastern Neb/western Iowa today. Pacific and western Gulf moisture
wrapping around the lee-side low will continue across the CO
Rockies which are under the trough today with snow levels dropping
to around 5000ft. Day 1 snow probs for >6" additional snow after
12Z are 40-90% across the CO Rockies and the higher ranges through
central WY.

Those low snow levels will allow snow accumulation on the central
High Plains this afternoon west of the low track. Decent TROWAL
development from the strengthening low will allow fgen bands of
snow to form, first over the Denver metro, then extending northeast
from there across western Neb up into SD today. 00Z HREF mean snow
rate reaches 1"/hr over the Palmer Divide this afternoon and over
the eastern edge of the Neb Panhandle this evening.
Filling/weakening of the low then brings down the banded snow
threat for eastern SD and southern MN overnight. However,
redevelopment as the low approaches Lake Superior brings about
renewed banded snow threats to the northern WI/MN border, far
northern WI, and the western U.P. late tonight into Saturday. Day 2
snow probs for >2" are limited to around the Porcupine Mtns into
the Keweenaw Peninsula.

Mixed precip is expected near the low track today with Day 1 PWPF
for >0.1" ice 20-40% over southwestern to central MN.


...Northeast...
Days 1/2...

Shortwave trough over lower Upstate NY early this morning shifts
off Cape Cod by midday with ongoing freezing rain NW of Boston
lingering this morning. WAA ahead of the low crossing northern MI
tonight brings light precip to northern New England late tonight
into Saturday. Residual cold surface air brings a freezing rain
threat to the White Mtns of NH through western/northern Maine. Day
1.5 PWPF for >0.1" is 40-70% through this region.


...WA Cascades...
Day 3...

Powerful shortwave trough rounding a southern AK low directs
elevated Pacific moisture through WA on Sunday. Snow levels rise on
the WA Cascades to around 5000ft Saturday night before dropping to
around 4000ft Sunday under height falls. Day 3 PWPF for >6" snow is
40-80% above Snoqualmie Pass level on the northern WA Cascades.


Jackson



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FOUS11 KWBC 061907
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
207 PM EST Fri Mar 6 2026

Valid 00Z Sat Mar 07 2026 - 00Z Tue Mar 10 2026


...Rockies, Central/Northern Plains and Upper Midwest...
Day 1...

A complex evolution of the longwave trough is unfolding this
afternoon as an embedded shortwave trough currently over the CO
Rockies will head northeast and become the primary feature in
producing snow and ice over the Midwest. Snow will continue to fall
over the CO Rockies this afternoon and early evening, but taper off
by Saturday morning as the 500mb shortwave departs. A 300mb jet
streak aloft will place its diffluent right-entrance region over
the Central Plains and Upper Midwest this afternoon and into
tonight as anomalous PWATs stream out ahead of the trough. Narrow
stripes of 850mb and 700mb FGEN are expected to orient themselves
in a SW-NE fashion from the Denver metro area and western NE to as
far north and east as northern MN this afternoon and overnight.
Some CAMs are showing the potential for up to 1"/hr snowfall rates
in these areas through this evening, along with modest over-running
at low-levels that causes freezing rain across northeast NE,
eastern SD, northwest IA, and into both MN and the western Great
Lakes. As surface low pressure deepens over WI Saturday morning,
banded snow will persist over central MN and the MN Arrowhead with
an icy wintry mix that is likely to impact the Twin Cities and
parts of MI's Upper Peninsula (U.P.). The U.P. will transition to
snow late morning and taper off by sunset.

WPC probabilities show a narrow area of moderate-to-high chances
(50-70%) for over 2" of snowfall from northeast CO on north and
east into west-central NE. There some some models members that show
the potential for >4" accumulations within this band of snow, which
could expand into southeast SD and central MN as well. The WSSI
does depict Minor Impacts from the Denver metro area from ongoing
snow this afternoon into western NE and southern SD. Meanwhile, ice
will become more problematic from NE's Sand Hills on north and east
through eastern SD and central MN given moderate-to-high chances
(50-80%) for ice accumulations over one-hundreth of an inch.
Southwest MN sports low-to-moderate chances (30-50%) for ice
amounts over one-tenth on an inch. Expect hazardous travel
conditions, particularly tonight and early Saturday morning. Most
roads should quickly improve by midday as the surface temps warm
above freezing for many (exceptions northern MN and the U.P. of MI)
and the higher March sun angle forces most roadways to melt any
lingering ice that is exposed to sunlight.


...WA Cascades & Lewis Range...
Days 2-3...

Early Sunday morning will mark the the arrival of the next slug of
Pacific moisture that supports periods of snow in the Cascades and
the Lewis Range. Not only will there be a moisture supply amidst
westerly upslope flow, but falling 500-700mb heights and a cold
frontal passage will force higher snow levels to drop below 3,00f0t
in the northern WA Cascades, and to as low as 4,000ft in the
southern WA Cascades. Farther east, snow levels initially over
6,000ft in elevation Saturday night will drop to as low as 5,000ft
in the Lewis Range and Glacier Nat'l Park. Any higher, more remote
elevation snowfall Saturday night will descend to pass level in the
Cascades on Sunday with high chances (>70%) for snowfall totals

6" over Snoqualmie Pass through Sunday afternoon. There are low-

chances (10-30%) for as much as 12" around Snoqualmie pass as well,
indicating there is a more snowy and impactful scenario at play for
the pass. In the Lewis Range, WPC probabilities show moderate-to-
high chances (50-70%) for snowfall totals >4" with low chances
(10-30%) for isolated amounts over 12" in the more remote peaks.
The WSSI-P between 00Z Sun - 00Z Mon depicts moderate-to-high
chances (50-80%) for Minor Impacts from Snoqualmie Pass on north
through the northern WA Cascades, while Glacier Nat'l Park
elevations over 6,000ft sport moderate chances (40-60%) for Minor
Impacts.


Mullinax




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FOUS11 KWBC 070853
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
353 AM EST Sat Mar 7 2026

Valid 12Z Sat Mar 07 2026 - 12Z Tue Mar 10 2026


...Upper Midwest...
Day 1...

Surface low center tracks northeast from WI early this morning
across northern MI through midday. Strung out comma head fgen
banding over southern MN lifts northeast across northern WI and the
western U.P. this morning. Right entrance jet dynamics aid lift and
allow snow rates around 0.5"/hr per 00Z HREF around 12Z in the
Bayfield area of WI and along the western U.P. shore/Porcupine
Mtns. Snow lifts northeast of the Keweenaw Peninsula by noon.


...New Hampshire and Maine...
Day 1...

Warm air advection rain ahead of a trough is currently entering
western NY. This shifts to the White Mtns of NH and Maine later
this morning where subfreezing temps persist inland from the coast
as high pressure continues to retreat over Atlantic Canada. Day 1
PWPF for >0.1" are 20-30% in the interior terrain of Maine and the
White Mtns of NH.


...Washington to Northern Rockies...
Days 2-3...

A trough shifts over the Gulf of Alaska today before digging south
down the BC coast through Monday. A tight baroclinic zone
accompanies this trough with a powerful onshore jet and enhanced
moisture that pushes into Washington early Sunday. Snow levels
around 6000ft in the moisture surge Sunday morning steadily
decrease through Sunday night, reaching around 500ft by 12Z
Monday. Will need to monitor precip likelihood for the Seattle
metro given Olympic shadowing in the westerly flow, but there is a
chance for snow down near sea level particularly (from a thermal
perspective) Monday night.

Otherwise it's terrain based snowfall late Sunday night through
most if not all of next week. This streams east across NW MT where
snow levels will be 1000ft or less starting Monday. Day 2 snow
probs for >6" are 50-90% for the WA Cascades and the Lewis Range in
Glacier NP. These probs expand down to Mt Hood for Day 3 and well
below pass level on the WA Cascades. The axis shifts south a bit
inland with Day 3 snow probs for >6" over the Bitterroots and
northern Absarokas in the 30-60% range.


Jackson



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FOUS11 KWBC 072059
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
359 PM EST Sat Mar 7 2026

Valid 00Z Sun Mar 08 2026 - 00Z Wed Mar 11 2026

...Pacific Northwest...

Days 1-3...

A strong Eastern Pacific ridge axis over the Northwest is forecast
to flatten tonight amid strong height-falls from a digging trough
in the Gulf of Alaska. Accordingly, strong zonal onshore flow
will set in across the Pacific Northwest by early tomorrow. As
highlighted overnight, snow levels in the prefrontal airmass will
be quite high to begin Sunday -- around 6-7000 feet, but should
decrease to 500-1000 feet by Monday morning. Thus, snowfall in the
Day 1 period should be relegated to the northern reaches of the
Cascades, where the latest PWPF shows 60% probabilities for >4"
atop Stevens Pass. The unsettled pattern will continue into next
week as a digging jet-streak and shortwave approach on Monday,
leading to renewed snowfall at and below pass level. By Days 2-3,
snow probs for >6" are 50-90% for the WA Cascades and the Olympics.


...Northern Rockies to the Upper Midwest...

Late Day 2-3...

Snowfall is expected to expand along the northern flank of a
developing lee-side low on Monday. A lingering Pacific moisture
plume, superimposed with a corridor of 850-700 mb frontogenesis
and right entrance ascent will lead to an east-west translating
area of snowfall atop the Northern Plains and Upper Midwest. The
progressive nature of this band should limit overall snowfall
amounts however, evidenced by the latest PWPF which shows 20%
probabilities of >4" in Northeast MN.

Asherman/Jackson






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FOUS11 KWBC 080849
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
449 AM EDT Sun Mar 8 2026

Valid 12Z Sun Mar 08 2026 - 12Z Wed Mar 11 2026

...Pacific Northwest Through The Northern Rockies...

Days 1-3...

Deep mid-level low drifts southeast over the Gulf of Alaska today
through Monday with the trough south of it digging across
Washington with a strengthening zonal jet before stalling/lifting
north through midweek. Snow levels over the WA Cascades drop
through Monday morning from the current 6000ft to near sea level
Monday/Monday night. The first slug of moisture from this system is
currently pushing down the south end of Vancouver Island with
higher elevation 1"/hr snow rates over the north WA Cascades per
the 00Z HREF. Then renewed precip arrives this evening when snow
levels dip below 3000ft/Snoqualmie Pass level and reach 1000ft or
less by 12Z Mon. Onshore flow and precip persist pretty much
through the rest of this week in western WA. Will need to continue
to monitor Puget Sound convergence banding Monday night when snow
levels approach sea level for accumulating snow potential in the
greater Seattle metro. Otherwise, it's upslope based snow for the
WA Cascades with and inland axis shifting south down the MT Rockies
this afternoon through Monday with snow levels in the moderate
precip rates generally 4000-6000ft. Day 1 snow probs for >6" are
around 50% near Snoqualmie Pass and 50-80% in the higher NW MT
Ranges including the Lewis and Bitterroots. Day 2 snow probs for

8" are 60% near Snoqualmie Pass and 30-50% in the northern/Red

Lodge Absarokas. Day 3 snow probs for >8" are 85% near Snoqualmie
Pass and 30-60% in the Bighorns of northern WY.
The prolonged duration of moderate to heavy snow for the WA
Cascades at low snow levels through midweek will be quite
remarkable.


...Northern Great Lakes...

Day 3...

A reinforcing trough rounding the Gulf of Alaska low today digs
across WA late Monday where it begins to draw the cutoff low
currently off the northern Baja Peninsula toward Texas. The sheared
southern stream remnant trough and the northern stream trough from
WA approach each other Tuesday night over the south-central Plains,
promoting strong inverted troughing downstream across the Midwest.
North of this trough axis will be overrunning precip with a
transition from a wintry mix to snow. These defined ptype changes
will need to be closely monitored as accumulating ice and snow are
likely. Day 3 snow probs for >4" are 40% in the MN Arrowhead and
30% in the western coastal U.P. South of this swath is the risk for
freezing rain with probs for >0.1" currently 10-30% over the
eastern U.P. and northern L.P. Since the low will track along/near
the axis of the inverted trough, duration of wintry precip over the
northern Great Lakes will persist into/through Wednesday, so stay
tuned for updated location and magnitude forecasts for snow and
ice.


Jackson


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FOUS11 KWBC 081924
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
324 PM EDT Sun Mar 8 2026

Valid 00Z Mon Mar 09 2026 - 00Z Thu Mar 12 2026

...Pacific Northwest Through The Northern Rockies...

Days 1-3...

An active period of winter weather is expected through mid-week as
onshore flow persists through the period, culminating in a
potentially long duration atmospheric river (AR) beginning on D3.

The period begins with generally zonal mid-level flow encompassing
the Pacific Northwest, spreading moisture onshore ahead of a cold
front that will steadily drop southeast through Monday morning.
This cold front will be suppressed by a strung out lobe of
vorticity otherwise embedded within the zonal flow, and persistent
850mb winds nearly orthogonal to the coast will help advect at
least modest moisture onshore, with ascent into this plume aided by
the cold front and the LFQ of an upper jet streak. Additionally,
the orthogonal low-level winds will upslope favorably into the
Olympics and Cascades to enhance precipitation in those ranges.

While some moisture will additionally spill over into the Northern
Rockies, the heaviest snowfall is expected farther west across the
Pacific Northwest terrain. This is also where snow levels will
become extremely low, falling to around 500 ft west of the WA
Cascades, and as low as the surface to the east. Here, WPC
probabilities D1 are high (>70%) for at least 6 inches of snow for
the Olympics and WA Cascades, especially above 1000 ft, so
significant impacts to pass-level travel is expected. While
accumulations below 500 ft should be minimal, some lowland
"conversational" snow is possible, which has been rare this winter.
Additional modest accumulations are likely farther east as well,
as reflected by WPC probabilities that reach as high as 50% for 6+
inches near the Lewis Range of MT.

Some modest wintry precipitation will continue into D2, but with
lighter intensity and less coverage.

During D3, however, the more significant event begins as the more
notable AR spreads onshore. All local landfall tool probabilities
(from CW3E) suggest a west-to-southwest AR with high probabilities

80%) for at least 500 kg/m/s IVT coming onshore in southern WA

late D3. This will be funneled eastward ahead of a cold front such
that the highest IWV will be in a narrow channel that gradually
sinks southward with time (possibly just beyond the current D3
forecast period). Regardless, there is high confidence in this AR
bring copious moisture onshore as reflected by NAEFS PW percentiles
exceeding the 90th percentile by the end of the forecast period.
Snow levels will climb briefly during the most intense period of AR
conditions thanks to the accompanying WAA, but they start very low,
around 1500 ft, so even the steady climb through 00Z/Thursday only
rises snow levels to around 4000 ft. This suggests that the
important passes will remain primarily snow through the event
(since snow levels fall again into D4), and with prolonged IVT and
pronounced upslope flow into the cold column, widespread and
impactful heavy snow is likely to result.

Current WPC probabilities D3 are already over 70% for 12+ inches in
the Olympics and much of the WA Cascades, with high probabilities
for 4+ inches expanding down into the Foothills. Moisture spilling
over into the Northern Rockies will also cause heavy snowfall as
reflected by WPC probabilities D3 that are as high as 30-70% for 6+
inches. Additional snowfall is anticipated much of D4 as well as
this prolonged event unfolds into the medium range period.


...Northern Plains to Northern Great Lakes...

Day 3...

A northern stream and southern stream trough will push east into
the Plains Tuesday night, reflected by dual shortwaves advecting
through the flow. Although these features are not progged to
directly interact this forecast period, increasing downstream moist
advection from the Gulf (and around the periphery of a southeast
ridge) will spread impressive IVT (an AR) anti-cyclonically around
the ridge to support expanding heavy precipitation from the
Southern Plains into the Northern Plains and eastward towards the
Great Lakes. This precipitation will be enhanced by a developing
low pressure downstream of the northern stream trough (with ascent
aided by a meridionally surging jet streak), and north of this
surface low a mix of wintry precipitation types is expected.

The amount and location of any significant accumulation of snow
and/or ice is still uncertain due to considerable model spread.
However, there is increasing confidence that a stripe of heavy
snow will develop in response to overrunning/isentropic upglide
northwest of a surface front from Minnesota through the U.P. of
Michigan. Here, strong fgen, especially within the 700-600mb layer
which intersects the DGZ, will drive a narrow corridor of heavy
snowfall with rates potentially reaching 1"/hr at times. The
heaviest snowfall is likely from just northeast of the Twin Cities
through the eastern U.P. of MI where WPC probabilities for 4+
inches of snow reach 10-50%, and locally 8+ inches of snowfall is
possible in the higher elevations of the U.P.

Farther south, a mixed of snow, sleet, and freezing rain will
contribute to a strip of moderate ice accumulations. WPC
probabilities for 0.01" of ice are above 30% from southern WI
through the northern half of the L.P. of MI, with locally more than
0.1" possible (30-50% chance) near the Tip of the Mitt.


...Northern New England...
Day 3...

A low pressure system emerging from the Great Lakes will track
steadily northeast into Ontario by 00Z Thursday. Downstream of this
low, a warm front will stretch ENE into New England, and then lift
northward towards Canada as heights bulge over the area, and the
accompanying WAA drives into the boundary. This synoptic evolution
will occur downstream of an impressive trough axis digging through
the middle of the country, with impressive IVT surging out of the
Gulf to produce an atmospheric river (AR) around the periphery of
the southeast ridge. This moisture will manifest as extreme PWs
into New England (PW anomalies as much as +4 sigma) to expand
precipitation into the area. While the column will generally be
much too warm for wintry precipitation, mixed snow/sleet/freezing
rain is likely along the international border with Canada, with the
most significant accumulations likely in northern Maine. Here,
WPC probabilities for at least 2" of snow are as high as 70-90% in
far northern Maine, with probabilities above 10% for ice exceeding
0.1" confined to the terrain of western ME.



Weiss



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FOUS11 KWBC 090910
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
510 AM EDT Mon Mar 9 2026

Valid 12Z Mon Mar 09 2026 - 12Z Thu Mar 12 2026

...Pacific Northwest Through The Northern Rockies...

Days 1-3...

Active winter weather continues across the WA Cascades and northern
Rockies through this weekend with particularly low snow levels
(especially for March) persisting into Wednesday.

A powerful zonal jet south of a Gulf of Alaska low will continue to
push across the WA/OR border as it continues to intensify to
150kt+ through tonight. A tight baroclinic zone has established
over central OR to southern MT with a moisture axis pushing across
western WA with showery activity through this evening under a
passing trough axis before tapering off under brief ridging
overnight. This is the coldest portion of this storm, but precip
should be pretty localized which may limit the snow coverage around
the greater Seattle metro tonight as snow levels dip below 500ft
MSL. Day 1 snow probs for >8" are over 50% above about 2000ft on
the WA Cascades and around 30% in the Bitterroots and just south
of Glacier NP.

Snow levels then rise to 1500ft on the Cascades Tuesday as
moisture content in the onshore flow increases along with snow
rates. Day 2 snow probs for >8" are over 50% above about 2500ft on
the WA Cascades and 40% for the Red Lodge/northern Absarokas and
higher Bighorns.

The next jet streak and onshore moisture surge increase is
Wednesday, again right into western WA. Snow levels quickly rise
above 3000ft Wednesday afternoon with high precip rates. Day 3 snow
probs for >12" are over 50% above 3500ft and around 60% in the
Bitterroots and Lewis Range. At least two more days of heavy
mountain snow, so stay tuned for further details on that forecast.


...Northern Plains through the Northern Great Lakes...

Days 2-3...

A southern stream cutoff low off Baja will eject east and open into
a trough before reaching TX Tuesday night. Considerable
sub-tropical Pacific moisture will stream across Mexico and be
joined by west Gulf moisture that surges up the Plains. Meanwhile a
northern stream trough crosses the northern Rockies Tuesday with
an inverted trough developing from the southern Plains to Chicago
Tuesday night with surface low development over southeast MI early
Wednesday. The surging moisture will wrap around the surface
trough/developing low, forming a comma head and connecting fgen
band over SD to southern MN Tuesday night. North of the low track
expect swaths of wintry mix before being all snow over far northern
WI and the U.P. Confidence is rising on a dry slot extending
through this wintry mix zone which complicates the QPF in this
case. There is decent storm track and QPF coverage from the 00Z
AIGFS/EC-AIFS and GFS on heavy banded snow over the U.P. and
sufficient QPF over the wintry mix zone for concerning freezing
rain accumulations. Day 2.5 snow probs for >6" are 40% in the Huron
Mtns and 30% along the central U.P. northern shore though these do
seem a bit suppressed. Ice probs have risen despite the risk for
dry slotting with the northeast L.P. having Day 2.5 probs for

0.25" peak around 40%. Interestingly the WSSI-P moderate impact

ice has a peak around 50% in a similar area. Overall this is a
fairly progressive storm, much more so than the prolonged ice storm
last March in this area.


...Northern New England...
Days 2/3...

Surface low pressure downstream of a northern stream trough
over the Upper Midwest tracks across New York on Wednesday before
crossing northern New England Wednesday night. A warm front
downstream of the low will extend ENE into New England, and then
lift through northern Maine with strong moisture advection driving
a warm nose over residual cold air from high pressure tracking
north of Maine Tuesday night. A wintry mix of sleet and freezing
rain spreads generally north of NY/VT and across north-central
Maine where Day 3 ice probs for >0.1" are 40-60%. Thermals likely
remain cold enough for the northern tip of Maine where Day 3 snow
probs for >6" are 40-60% in northern Aroostook Co.


Jackson



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FOUS11 KWBC 091802
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
202 PM EDT Mon Mar 9 2026

Valid 00Z Tue Mar 10 2026 - 00Z Fri Mar 13 2026

...Pacific Northwest Through The Northern Rockies... Days 1-3...

Active winter weather continues across the WA Cascades and northern
Rockies through this weekend with particularly low snow levels
(especially for March) persisting into Wednesday.

A powerful zonal jet south of a Gulf of Alaska low will continue to
push across the WA/OR border as it continues to intensify to
150kt+ through tonight. A tight baroclinic zone has established
over central OR to southern MT with a moisture axis pushing across
western WA with showery activity through this evening under a
passing trough axis before tapering off under brief ridging
overnight. This is the coldest portion of this storm, but precip
should be pretty localized which may limit the snow coverage around
the greater Seattle metro tonight as snow levels dip below 500ft
MSL. Day 1 snow probs for >8" are over 50% above about 2000ft on
the WA Cascades and around 30% in the Bitterroots and just south
of Glacier NP.

This initial round of wintry precipitation pushes east late D1 into
D2, but is quickly followed by a resurgence of heavier
precipitation. This secondary swath of precipitation will be driven
by an impressive westerly AR, which will move onshore near 45N
after 00Z/Wednesday, and then maintain elevated IVT intensity (>250
kg/m/s) through a long duration, continuing through the end of the
forecast period. Both the ECENS and West-WRF ensemble probabilities
suggest the most significant IVT will occur 00Z/12 - 00Z/13,
during which time snow levels will rise to as high as 4000 ft in
WA, but 6000 ft in OR, thanks to a sharp cold front demarcating the
highly variable snow levels. In general, though, snow levels will
be quite low, and with the prolonged AR continuing the latter 2/3
of the forecast period, this will result in periods of moderate to
heavy snow, especially across the Olympics and Cascades where the orthogonal/onshore flow will drive pronounced upslope enhancement
to snow amounts.

WPC probabilities D2 for heavy snow indicate a high risk (>70%) for
at least 12 inches of snow across the WA Cascades and Olympics,
with considerable impacts to pass-level travel expected at all the
Cascade passes since heavy snow is expected above 2500 ft. Locally
more than 2 feet is expected D2 in the higher crests and peaks. Lighter,
but still significant snow (>4") is likely into the OR Cascades
and Northern Rockies.

During D3, there is little adjustment to the footprint of heavy
snow as the westerly AR continues with little latitudinal
fluctuation. The biggest difference will be across OR where snow
levels climbing to as high as 6000 ft shuts down the pass-level
concerns in the OR Cascades. However, heavy snow continues above
3000 ft (or lower in the northern WA Cascades and Northern Rockies)
where WPC probabilities remain above 70% for an additional 12+
inches of snowfall, and compounding pass-level impacts at locations
such as Snoqualmie and Stevens Passes leading to extremely
dangerous travel. Additionally, this snow will have a generally low
SLR, so the combination of heavy rates and the heavy-wet nature of
the snow, over a prolonged period of time, could result in
widespread major impacts across the Cascades as reflected by the
recent WSSI-P.


...Northern Plains through the Northern Great Lakes...
Days 1-2..

Northern and southern stream shortwaves will cross the country
from the west, reaching the Plains by Wednesday morning. Although
these features will remain separate, downstream moisture advection
will steadily intensify, with impressive IVT exceeding 500 kg/m/s
surging northward from the Gulf suggesting an atmospheric river
(AR), which is also modeled by the recent PSL ARDT tool by late
Tuesday night. This will surge impressive moisture (PWs reaching +4
sigma into the Great Lakes), into which a developing low pressure,
aided by broad synoptic ascent, will develop to expand
precipitation across the area. As the low develops and moisture
expands, mid-level isentropic ascent/WAA will lead to a narrow
corridor of fgen between 700-600mb, resulting in a stripe of
moderate to heavy snow from South Dakota through Minnesota and into
the U.P. of Michigan. Snowfall rates of 1"/hr or more are possible
within this expanding band of snow, and while this should
accumulate efficiently, the duration of heavy snow is expected to
be limited, reducing the potential for widespread significant
accumulations. Still, WPC probabilities are moderate (30-70%
chance) for at least 4 inches of snowfall from far northern WI
through the U.P. of MI, with more than 2 inches likely anywhere
along this band from eastern SD through the Great Lakes.

South of this heavy snow band, an axis of significant freezing rain
is likely as the accompanying WAA pushes a warm nose >0C northward
through eastern Wisconsin and the L.P. of Michigan. As this occurs,
surface temperatures will remain below freezing thanks to weak E/NE
winds flowing out of a surface high pressure to the northeast to
keep wet-bulb temperatures below freezing. The duration of freezing
rain in a narrow corridor could be significant, especially from
near the Door Peninsula of WI through the northern L.P. of MI, but
temperatures right around 0C will somewhat limit accretion
efficiency. Still, WPC probabilities indicate a high chance of at
least 0.01" of ice from central WI through much of the L.P. of MI,
with locally more than 0.25" possible east of Traverse City and
towards the Tip of the Mitt. Any freezing rain accretions above
0.25" could result in local infrastructure impacts, and the
Wednesday morning commute will likely be treacherous in these
areas.


...Northern New England & Eastern Great Lakes...
Days 2-3...

Potent northern stream shortwave lifting steadily eastward from the
Central Plains will cross into the Great Lakes/Ohio Valley Thursday
while amplifying. Downstream of this trough amplification, a
meridionally arcing jet streak will favorably influence ascent
through the RRQ to help strengthen a surface low tracking from
lower Michigan into Ontario, and then eventually moving over
northern Maine Thursday morning. Downstream of this system,
moisture advection will intensify from the Gulf, driven by potent
850mb WAA, which will additionally surge the surface warm front
northward. The combination of the deep layer ascent with the
resulting fgen (as a result of the WAA) will create heavy
precipitation along the international border with Canada and then
into northern Maine. Precipitation will likely start as snow across
northern Maine, but everywhere else, and then later in the period
across northern Maine, a mix of sleet and freezing rain, eventually
becoming rain, is expected, as the warm nose surges northward. The
guidance has trended slightly warmer the past few runs, but heavy
snow rates exceeding 1"/hr are likely in Northern Maine,
contributing to a high risk (>70% chance) for at least 4 inches of
snow, with locally 6-8 inches possible. Elsewhere, ice will likely
be the primary hazard, with WPC probabilities indicating a moderate
risk (30-70% chance) of at least 0.1 inches of ice in the northern
Adirondacks, northern New Hampshire, and parts of north-central
Maine.

As this low pulls away, strong CAA in its wake may result in
periods of moderate to heavy lake effect snow (LES) across Upstate
New York. Regional soundings indicate a modest environment for
heavy rates, but where the flow is most uniform across the Lakes,
WPC probabilities indicate a moderate risk (30-70%) for at least 2
inches of snowfall along the Chautauqua Ridge and into the Tug Hill
Plateau, with local amounts above 4 inches possible.


Weiss


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FOUS11 KWBC 100908
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
508 AM EDT Tue Mar 10 2026

Valid 12Z Tue Mar 10 2026 - 12Z Fri Mar 13 2026

...Cascades Through The Northern Rockies...
Days 1-3...

...Washington Cascades Blizzard into Thursday...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with particularly low snow levels
(especially for March) persisting through tonight.

A reinforcing shortwave trough rides a 150kt zonal jet positioned
south of a Gulf of Alaska low across the WA/OR border today. Low
snow levels (500ft or below) persist this morning over western WA
under the trough with snow levels rising to 1500ft this afternoon
as heights rise after the trough axis passage. Onshore flow
persists today with the next atmospheric river approaching tonight
with rates becoming moderate overnight with increasing winds. Day
1 PWPF for >8" is around 60% at Snoqualmie Pass and over 40% above
about 2000ft on the WA and northern OR Cascades as well as the
Olympics.

A focused axis of 0.75 to 1" PW shifts across the western WA/OR
border Wednesday through Friday with a trough axis crossing early
Thursday. Powerful winds accompany the leadup to the trough axis
with 850mb winds of 40-60kt expected across the WA and northern OR
Cascades Wednesday night before easing into the 25kt range on
Thursday. Snow levels rise to 4000ft through Wednesday in the WAA
of the AR axis before dropping over WA into the 2000-3000ft range
late Wednesday night. Days 2/3 snow probs for >12" are quite
impressive, generally 50-80% above about 2500ft on Day 2 and 2000ft
on Day 3. Blizzard warnings are up for the WA Cascades through
Wednesday with the watch extending into Friday for this prolonged
event.

This moisture axis extends inland over the northern Rockies through
this event. Snow levels rise there into the 4000-5000ft range
through Wednesday night before the moisture axis shifts south a bit
Thursday. Day 2 snow probs for >8" are 50-80% for the Bitterroots
through the Lewis Range before focusing on the Bitterroots,
Anaconda Range and southern Lewis Range on Day 3.


...Northern Plains through the Northern Great Lakes...
Days 1-2..

Broad troughing over the northern tier of the CONUS focuses onto a
more defined northern stream trough over the northern Rockies today
which sweeps across the northern Plains tonight, the Upper Midwest
Wednesday, and the Great Lakes Wednesday night. A sinewy band of
moderate snow over north-central MN, northern WI, and the western
U.P. is from fgen on the leading edge of a developing inverted
trough developing downstream of the forming trough axis. An
additional factor in the developing storm is a cutoff low currently
over the Sea of Cortez that ejects to TX through tonight. This
reinforces the downstream inverted trough and promotes surface low
pressure development over IL tonight. Broad cyclonic flow develops
tonight with fgen snow banding over the north-central Plains
through central MN up through northern WI and the western U.P.
pivoting down to eastern Neb. Dry slotting is well defined now in
guidance south of the snow and north of the surface low. Mixed
precip will develop through this zone over central WI and
especially northern L.P. of MI. Day 1.5 snow probs for >4" are over
40% from northern WI through the north shore of the eastern U.P.
with embedded 60% probs for >8" in the Huron Mtns. Day 1.5 probs
for >0.25" are 40-60% in the northern U.P. east of I-75.


...Far Northeast...
Days 2-3...

Potent northern stream shortwave lifting steadily eastward from the
Central Plains will cross into the Great Lakes/Ohio Valley Thursday
while amplifying. Downstream of this trough amplification, a
meridionally arcing jet streak will favorably influence ascent
through the right entrance region to help strengthen a surface low
tracking from lower Michigan through Ontario, before tracking north
of Maine late Wednesday night. Downstream of this system, moisture
advection will intensify from the Gulf, driven by potent 850mb
WAA, which will additionally surge the surface warm front
northward. The combination of the deep layer ascent with the
resulting fgen (as a result of the WAA) will create heavy
precipitation along the international border with Canada and then
into northern Maine. Precipitation will likely start as snow across
northern Maine, but everywhere else, and then later in the period
across northern Maine, a mix of sleet and freezing rain, eventually
becoming rain, is expected, as the warm nose surges northward. Day
2 ice probs for >0.25" are 30-50% in interior north-central Maine
with Day 2 snow probs for >6" limited to northern Aroostook Co.

Some LES can be expected in the wake of this low off Lake Ontario
late Thursday.


...Northern Plains to Northern Great Lakes...
Day 3...

The potent shortwave trough axis crossing northern WA early
Thursday really amplifies over the northern Plains Thursday before
rapidly developing into a major low pressure system over the Upper
Midwest Thursday night. This progressive system will be on the
leading edge of a 150kt WNWly jet. A strong wind field and heavy
snow bands will develop with this low. Day 3 snow probs for >6" are
30-60% over northeast ND and across northern WI, much of the U.P.,
and the North Shore of MN. This coming on the heels of the
low tonight into Wednesday will make for a notable late-season
impact to the Upper Midwest/northern Great Lakes.


Jackson



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FOUS11 KWBC 101842
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
242 PM EDT Tue Mar 10 2026

Valid 00Z Wed Mar 11 2026 - 00Z Sat Mar 14 2026

...Cascades Through The Northern Rockies...
Days 1-3...

...Washington Cascades Blizzard into Thursday...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with particularly low snow levels
(especially for March) persisting through tonight.

The overall synoptic pattern for D1 and beyond remains very
consistent with run-to-run continuity. A reinforcing shortwave
trough has continued to ride a 150kt zonal jet positioned south of
a Gulf of Alaska low across the WA/OR border as evidenced by the
first precipitation output located along the WA coastal areas. Low
snow levels (500ft or below) persist this morning over western WA
under the trough with snow levels rising to 1500ft this afternoon
as heights rise after the trough axis passage. Onshore flow
persists today with the next atmospheric river approaching tonight
with rates becoming moderate overnight with increasing winds. Day 1
PWPF for >8" is around 60-70% at Snoqualmie Pass and over 40%
above about 2000ft on the WA and northern OR Cascades as well as
the Olympics.

A focused axis of 0.75 to 1" PW shifts across the western WA/OR
border Wednesday through Friday with a trough axis crossing early
Thursday. Powerful winds accompany the leadup to the trough axis
with 850mb winds of 40-60kt expected across the WA and northern OR
Cascades Wednesday night before easing into the 25kt range on
Thursday. Snow levels rise to 4000ft through Wednesday in the WAA
of the AR axis before dropping over WA into the 2000-3000ft range
late Wednesday night as noted within the negative temperature
advection regime focused between 850-700mb. Days 2/3 snow probs for

12" are quite impressive, generally 50-80% above about 2500ft on

Day 2 and 2000ft on Day 3. Blizzard warnings are up for the WA
Cascades through Wednesday with the watch extending into Friday for
this prolonged event.

This moisture axis extends inland over the northern Rockies through
this event. Snow levels rise there into the 4000-5000ft range
through Wednesday night before the moisture axis shifts south a bit
Thursday. Day 2 snow probs for >8" are 50-90% for the Bitterroots
through the Lewis Range before focusing on the Bitterroots,
Anaconda Range and southern Lewis Range on Day 3.


...Northern Plains through the Northern Great Lakes...
Days 1-2..

Broad troughing over the northern tier of the CONUS focuses onto a
more defined northern stream trough over the northern Rockies today
which sweeps across the northern Plains tonight, the Upper Midwest
Wednesday, and the Great Lakes Wednesday night. Current WV
satellite and accompanying UA analysis indicates a defined
shortwave trough located over the north-central Rockies with a
broad diffluent upper pattern focused from the Mid-Mississippi
Valley up into the Lower Great Lakes. A sinewy band of moderate
snow over north- central MN, northern WI, and the western U.P. is
from fgen on the leading edge of a developing inverted trough
developing downstream of the forming trough axis. An additional
factor in the developing storm is a cutoff low currently over the
Sea of Cortez that ejects to TX through tonight. This reinforces
the downstream inverted trough and promotes surface low pressure
development over IL tonight. Broad cyclonic flow develops tonight
with fgen snow banding over the north-central Plains through
central MN up through northern WI and the western U.P. pivoting
down to eastern Neb. Dry slotting is well defined now in guidance
south of the snow and north of the surface low. Mixed precip will
develop through this zone over central WI and especially northern
L.P. of MI. Day 1.5 snow probs for >4" are over 40% from northern
WI through the north shore of the eastern U.P. with embedded 60-90%
probs for >8" in the Huron Mtns. Day 1.5 probs for >0.25" of ice
accretion are 50-80% in the northern U.P. east of I-75 with the
maxima focused around Alpena and points just south where guidance
is most aggressive with a prolonged freezing rain environment
through the storms life cycle.


...Far Northeast...
Days 2-3...

General pattern evolution remains unchanged with strong run-to-run
continuity for the setup. A potent northern stream shortwave
lifting steadily eastward from the Central Plains will cross into
the Great Lakes/Ohio Valley Thursday while amplifying. Downstream
of this trough amplification, a meridionally arcing jet streak will
favorably influence ascent through the right entrance region to
help strengthen a surface low tracking from lower Michigan through
Ontario, before tracking north of Maine late Wednesday night.
Downstream of this system, moisture advection will intensify from
the Gulf, driven by potent 850mb WAA, which will additionally surge
the surface warm front northward. The combination of the deep
layer ascent with the resulting fgen (as a result of the WAA) will
create heavy precipitation along the international border with
Canada and then into northern Maine. Precipitation will likely
start as snow across northern Maine, but everywhere else, and then
later in the period across northern Maine, a mix of sleet and
freezing rain, eventually becoming rain, is expected, as the warm
nose surges northward. Day 2 ice probs for >0.25" are 30-60% in
interior north-central Maine with Day 2 snow probs for >6" limited
to northern Aroostook Co.

Some LES can be expected in the wake of this low off Lake Ontario
late Thursday. Low-end probabilities (<20%) exist for snowfall of
at least 4" across the Tug Hill Plateau with the best chance for
snowfall more coincident with the evolving synoptic pattern across
Canada down through the North Country where 10-40% probabilities
exist for at least 4" of snowfall, mainly in the highest elevations
of the Adirondak's.


...Northern Plains to Northern Great Lakes...
Day 3...

The potent shortwave trough axis crossing northern WA early
Thursday really amplifies over the northern Plains Thursday before
rapidly developing into a major low pressure system over the Upper
Midwest Thursday night. This progressive system will be on the
leading edge of a 150kt WNWly jet. A strong wind field and heavy
snow bands will develop with this low. Day 3 snow probs for >6" are
40-70% across northern WI, much of the U.P., and the North Shore
of MN. This coming on the heels of the low tonight into Wednesday
will make for a notable late-season impact to the Upper
Midwest/northern Great Lakes where snowfall totals of 1-2ft will be
common across the North Shores of Superior over into the Michigan
U.P. where 18-24+" is forecast across the Huron Mountains and
neighboring Keweenaw Peninsula.

Jackson/Kleebauer


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FOUS11 KWBC 110909
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
509 AM EDT Wed Mar 11 2026

Valid 12Z Wed Mar 11 2026 - 12Z Sat Mar 14 2026

...Cascades Through The Northern Rockies...
Days 1-3...

...Washington Cascades Blizzard into Thursday...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with heavy precip and high winds
especially tonight.

A focused axis of 0.75 to 1" PW shifts across the western WA/OR
border through Friday night with a trough axis crossing tonight.
Powerful winds accompany the leadup to the trough axis with 850mb
winds of 40-60kt expected across the WA and northern OR Cascades
tonight before easing into the 25kt range on Thursday. Snow levels
currently in the 2000-3000ft range rise to around 5000ft this
afternoon in the WAA of the AR axis before dropping over WA into
the 2000-3000ft range late tonight as noted within the negative
temperature advection regime focused between 850-700mb. This will
be quite the snow event for the higher elevations of the WA
Cascades and the higher northern ID/northwestern MT ranges. Days
1-3 each have snow probs for >24" above 40% in the Cascades and 30%
in those ID/MT ranges (with only a little wobble in the axis south
on Day 2 before returning north for Day 3). Snow probs for >12" at
Snoqualmie Pass are 70% on Day 1, 95% on Day 2, and 70% again for
Day 3. Major impacts are expected across the WA Cascades, the
Bitterroots, western MT ranges and on Day 2 for northwestern WY
ranges.


...Northern Great Lakes and Far Northeast...
Day 1..

Northern stream trough over the Upper Midwest with southern stream
low over west Texas shift east to the Great Lakes/Southeast through
tonight. The surface low over northern IL rapidly develops as it
shifts across southern MI this morning and Quebec tonight. Banding
around the elongated 850mb low over WI/MI is continuing over the
U.P. with a separate area of light to moderate snow in central Neb.
This axis pivots more N-S through this morning before lifting into
Canada. Day 1 snow probs for >6" additional after 12Z are 50% in
the Huron Mtns and 20-40% in the eastern U.P. and far northern
Aroostook Co Maine.
Meanwhile WAA ahead of the low shifts across the eastern U.S. with
sufficient lingering cold over interior north- central Maine into
Coos Co NH where Day 1 ice probs for >0.1" are 40-80%. Ongoing ice
over the northern L.P. lingers this morning with 20% probs for an
additional 0.1" after 12Z in a swath of the northeastern part of
the state.


...Northern Plains through Northern Great Lakes into Northeast...
Days 2/3...

The potent shortwave trough axis crossing northern WA Wednesday
night on a 150kt potent WNWly jet really amplifies over the
northern Plains Thursday afternoon, producing a mature surface low
that crosses the northern Great Lakes Thursday night and pushes up
the St. Lawrence on Friday before reaching northern Maine Friday
night. A strong wind field and heavy snow bands will develop with
this low, though there remains some uncertainty with the track. The
EC-AIFS and CMC are farther south with a Day 2 QPF axis focused
just south of Duluth, while the GFS and NAM have the axis north
from Duluth. A compromised solution in between (WPC QPF actually
favors the south solution) is pretty close to the AIGEFS axis with
more magnitude. Day 2 snow probs for >6" are 40% over northern MN
with Day 2.5 probs 40-80% from the North Shore of MN, far northern
WI, and all of the U.P. and the northern L.P. This track then
continues east with Day 3 probs for >6" 40-60% over the Tug Hill
and southern Adirondacks. Unlike the previous system, this one is
much more simple with rain/snow and not a wintry mix. However, the
deep low will create quite a wind field with localized blizzard
conditions possible in spite of the North Woods' friction.


Jackson


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FOUS11 KWBC 111800
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
200 PM EDT Wed Mar 11 2026

Valid 00Z Thu Mar 12 2026 - 00Z Sun Mar 15 2026

...Cascades Through The Northern Rockies...
Days 1-3...

...Washington Cascades Blizzard into Thursday...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with heavy precip and high winds
especially tonight.

Very little deviation in the synoptic scale forecast across the
Pacific Northwest as the initial wave of the next AR takes aim at
WA/OR, protruding inland into the Northern Rockies. Recent 12z RAOB
out of KSLE (Portland, OR) and CONUS mesoanalysis confirms A
focused axis of 0.75 to 1" PW advecting into the WA/OR coast. The
expectation is for this advection regime to spread east across the
northern half of OR into WA state, eventually making progression
into the Northern Rockies as noted via a modest IVT pulse running
between 500-700 kg/ms. This will create a prolonged heavy snowfall
forecast within the terrain encompassing the Cascades into the
interior thanks to prevailing upslope flow lingering into the end
of the week (Friday PM). Shortwave trough currently off the WA
coast will advance eastward through the day today with powerful
winds preceding the mean shortwave trough axis with 850mb winds of
40-70kts expected across the WA and northern OR Cascades tonight
before easing into the 25-30kt range on Thursday as the trough
axis finally crosses the region by early Thursday morning.

Snow levels currently in the 2000-3000ft range rise to around
5000ft this afternoon in the WAA of the AR axis before dropping
over WA into the 2000-3000ft range late tonight as noted within the
negative temperature advection regime focused between 850-700mb.
This will be quite the snow event for the higher elevations of the
WA Cascades and the higher northern ID/northwestern MT ranges. Days
1-3 each have snow probs for >24" above 40% in the Cascades and
30% in those ID/MT ranges (with only a little wobble in the axis
south on Day 2 before returning north for Day 3). Snow probs for

12" at Snoqualmie Pass are 70% on Day 1, 95% on Day 2, and 70%

again for Day 3. Cumulative 72hr snowfall probability of >24" is
above 70% for a majority of the WA Cascades and across the
Bitterroots/ western MT ranges northwestern WY ranges with lower
(30-70%), albeit modest probabilities for the same threshold across
the Absoroka's down into the Wind River ranges in northwest WY and
bordering MT.


...Northern Plains through Northern Great Lakes into Northeast...
Days 2/3...

The potent shortwave trough axis crossing northern WA overnight
into tomorrow morning will quickly eject into the Northern Plains
and neighboring Alberta/Saskatchewan Provinces through Thursday
with sights downstream on the Upper Midwest and Great Lakes by the
second half of D2. A LER of a potent 150kt upper jet will really
help to amplify an accompanying surface low over the northern
Plains as it matures rapidly into a powerful mid-980s low as it
crosses into the northern Great Lakes Thursday night. Strong winds
and heavy snow will press northwest to southeast from northeast ND
through the northern-third of MN, eventually making headway into
the Michigan U.P by early Friday morning. The strong cyclone will
continue to move quickly eastward as it advances up into the St.
Lawrence on Friday before reaching northern Maine Friday night.

Day 2-2.5 snow probs for >6" are 40-80% over northern MN with the
highest probabilities centered along the North Shore of Lake
Superior in the Arrowhead of MN. D2.5-3 probabilities for >6" are
between 50-80% across far northern WI, all of the U.P., and the
northern L.P. This track then continues east with Day 3 probs for

6" 40-70% over the Tug Hill and southern Adirondacks. Unlike the

previous system, this one is much more simple with rain/snow and
not a wintry mix. However, the deep low will create quite a wind
field with localized blizzard conditions possible in spite of the
North Woods' friction.

Jackson/Kleebauer


$$

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FOUS11 KWBC 120753
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
353 AM EDT Thu Mar 12 2026

Valid 12Z Thu Mar 12 2026 - 12Z Sun Mar 15 2026

...Cascades Through The Northern Rockies...
Days 1-2...

...Washington Cascades Blizzard today...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with heavy precip and high winds
especially tonight.

Atmospheric river (AR) plunging onshore WA/OR will continue with
high probabilities (>90% chance) of exceeding 250 kg/m/s for IVT
continuing into Friday. This AR has been persistent, and will
maintain a westerly direction through landfall transporting
moisture orthogonally into the WA/OR coasts. This prolonged AR will
bring copious moisture onshore, with pronounced spillover reaching
all the way to the Northern Rockies as reflected by still high
probabilities (>90% chance) for IVT exceeding 250 kg/m/s today and
tonight.

This moisture will be wrung out as heavy precipitation through
orographic enhancement into the Olympics, Cascades, and Northern
Rockies, with additional heavy precipitation reaching the lower
elevations through mid-level isentropic ascent due to WAA. However,
a low pressure moving out of Alberta, Canada and into the Northern
Plains by Thursday aftn will drape a cold front southward, with
this front become elongated west to east causing some additional
upslope and mesoscale ascent, while additionally creating a sharp
gradient in snow levels. North of this front, snow levels will
waver between 1500-2500 ft, creating significant impacts at many of
the Cascades and Northern Rockies passes, especially during D1 when precipitation will be the heaviest. Farther south, snow levels will
remain elevated as high as 6000-7000 ft in Oregon, resulting in far
weaker winter related impacts through the period.

The precipitation will likely be nearly continuous across the
terrain, with only as low S/SE trend through Friday evening.
However, by Saturday, the ascent should advect away to the east
while the best moisture shunts to the southeast, bringing an end to
wintry precipitation across the area. Before that happens, periods
of heavy snow combined with strong winds will result in blizzard
conditions across the Olympics, WA Cascades, and parts of the
Northern Rockies near Glacier NP and the Lewis Range. With snow
levels so low, travel across the passes will be extremely impacted
as 1-2+"/hr snowfall combines with strong winds. Where this snow
accumulates most robustly, WPC probabilities are high (>70%) for at
least an additional 24", with locally 3-5 feet of snow expected in
the Cascades and highest Northern Rockies elevations, leading to
continued challenging travel across the passes.


...Great Lakes into the Northeast...
Days 1-2...

A fast moving, compact, but intense low pressure will race eastward
near the United States/Canada border from this morning through
Saturday morning, bringing a stripe of heavy snow and strong winds
to parts of the area.

This low will initially develop over the British Columbia province
Wednesday evening, but being to deepen rapidly as it approaches
North Dakota Thursday morning. This low will be driven by a potent
shortwave emerging from the Canadian Rockies and then deepening
into a closed low despite modest amplitude of the feature thanks to
being embedded within pinched westerlies and fast mid-level flow.
As this shortwave deepens, likely reaching peak amplitude 00Z/Fri -
12Z/Fri, it will work in tandem with the LFQ of nearly zonal, but strengthening, jet streak, to produce rapid ventilation aloft to
result in the surface low deepening quickly. This low is likely to
track from western ND to eastern WI on Thursday, and then continue
east, ejecting away from the Maine coast on Saturday morning.

As this low progresses east, especially into the Great Lakes, it
will interact with a moistening column thanks to residual IVT from
an atmospheric river spreading eastward from the Pacific Northwest.
PWs are progged to reach +2 sigma, with this moisture then being
advected cyclonically into the low, reflected by a strengthening
theta-e ridge /TROWAL/ lifting northward into the western Great
Lakes. Impressive deep layer ascent will then couple with
increasing isentropic ascent and 850-700mb fgen (in response to
intensifying WAA) to produce an environment will support heavy snow
rates for which the HREF suggests has a 70-90% chance of exceeding 1"/hr, especially along the Arrowhead and into the U.P. of MI. Although
there is still some latitudinal uncertainty as to where the
heaviest snow will occur, there is high confidence in a stripe of
heavy accumulations from northern MN through northern WI, the U.P.
of MI, and into the northern L.P. of MI. This is reflected by WPC
probabilities that are high (>70%) for at least 6 inches from far
northern MN into much of the U.P. and northern L.P. of MI, with
locally more than 12 inches possible across the Iron Ranges of the
Arrowhead.

Additionally, impacts will be considerable as these intense
snowfall rates combine with gusty winds that may reach 30-50 mph to
produce near blizzard conditions and dangerous travel. The WSSI-P
indicates a 20-40% chance of at least moderate impacts across the
Upper Midwest/Great Lakes, so the Thursday evening and Friday
morning commutes will likely be extremely challenging.

As this low skirts eastward on Friday into Saturday, it initially
occludes over MI and then pivots rapidly into New England Friday
night. During this time, the most significant ascent beings to wane
as the upper low opens and the best synoptic ascent no longer
overlaps within the LFQ of the accompanying jet streak. Impressive
WAA at 850mb will surge northeast from the Mid-Atlantic states into
the Northeast, helping to expand precipitation further despite a
reduction in available PW (compared to areas farther west). This
will likely still result in a swath of moderate snowfall from
Upstate NY through coastal ME, with again some continued
uncertainty into the latitudinal placement of the heaviest amounts.
The heaviest snow is likely in the upslope regions of the
Adirondacks D2 where WPC probabilities are high (>70%) for at least
6 inches, including across the Tug Hill Plateau, with lesser, but
still significant snowfall of 2-4" expected in the higher terrain
of the Green and White Mountains.


...Central Appalachians & I-95 Corridor...
Day 1...

A tricky forecast for snowfall will develop from the Central
Appalachians into the Mid-Atlantic states today. A powerful cold
front will race eastward from the Ohio Valley/Central Appalachians
tonight, to exit the Mid-Atlantic coast by late this afternoon.
Precipitation developing along the front will expand northeast and
become heavy within a plume of PWs above +3 sigma. This will
support primarily heavy rain as the column will be much too warm
for any wintry p-types. However, the intense CAA along and
immediately behind the front will drive tremendous ascent and
rapidly cool the column, aided by dynamic cooling as precipitation
falls from aloft. Cold air chasing moisture is rarely a setup that
supports snowfall, especially after record high-temperatures from Tuesday/Wednesday. However, a potent jet streak will try to
strengthen just as the cold front moves offshore, placing
sufficient deep layer lift atop the front to potentially change
precip over to heavy snow, aided by additional ascent downstream of
the primary southern stream shortwave/PV anomaly opening into the
Mid-Atlantic. This could support snowfall that could be heavy at
times thanks to strong omega into the DGZ.

The combination of intense lift into the DGZ at the same time as
the column cools (with steep lapse rates below 850mb) could support
a changeover to heavy snowfall, at least briefly, from northern NC
through Long Island. The timing of the changeover (afternoon)
combined with the antecedent hostile conditions (for snow
accumulation) will limit most impacts. However, the high-res is in
decent agreement that there will be a changeover to heavy snow with
rates potentially exceeding 1"/hr at times. This will likely not
materialize as 1"/hr accumulation, and any accumulations should be
limited to grassy surfaces as reflected by WPC probabilities that
are generally 10-30% for 1" of snow (higher in the higher terrain). However,
a wide range in WSE plumes suggests the potential for some
accumulation, especially along and east of I-95 or across the
higher terrain of the Blue Ridge, which could impact travel for the
evening commute as reflected by the WSSI-P supporting at least
modest probabilities for minor impacts.


...Northern High Plains through the Upper Midwest...
Day 3...

...Increasing confidence in a major winter storm this weekend...

The next in a series of shortwaves embedded within rapid flow
across the northern tier will move onshore the British Columbia
coast Friday and then advect rapidly southeast while deepening. The
core of this shortwave and its associated vorticity is expected to
dive across the Northern Rockies Saturday night and then reach the
central High Plains by Saturday night/Sunday morning. This
deepening trough across the High Plains will move across a residual
baroclinic gradient draped from the Northern Rockies into the
Central Plains, to help drive surface cyclogenesis in the lee of
the Rockies. This low is then likely to rapidly intensify as it
tracks northeast into Sunday, aided by coupling of upper level jet
streaks. Although there continues to be spread among the various
ensemble clusters, there is high confidence in this low developing
and reaching the Central Plains by the end of the forecast period.

This low will develop within impressive moisture, both in response
to persistent IVT spreading Pacific moisture onshore and across the
West, but also in response to an expanding theta-e ridge emerging
from the Gulf downstream of the amplifying trough axis. As this low
deepens, it will wrap this moisture northward through intensifying
isentropic ascent/WAA, leading to a large swath of heavy snow.

This heavy snow may begin as early as Friday across the northern
High Plains in response to impressive fgen driven both by the
low-level front and 700mb WAA and the response to the peripheral
RRQ of the zonally oriented jet streak aloft. It is this jet
streak overlapping the strengthening 700mb WAA, as it moves
eastward, which will allow snow to expand in a narrow corridor
across the High Plains into the Upper Midwest through Saturday
morning, and in some places there may be two rounds of moderate to
heavy snow. However, the most significant snowfall is expected to
begin Saturday night and then continue beyond this forecast period
from the Northern Plains into the Great Lakes. While it remains a
bit too early for specific forecast amounts, 2-day WPC
probabilities for at least 8" of snow are above 70% across the High
Plains of MT, and 30-70% for parts of SD and MN, and snowfall
rates above 1"/hr appear probable due to a synoptic evolution that
suggests impressive banding is likely.

These snowfall rates combined with an intense pressure gradient due
to a strong high positioned just to the northwest, will likely
cause significant blowing and drifting of snowfall, along with
limited visibility. WSSI-P is already projecting 70+% probability
for at least moderate impacts (mostly on D4 into the Upper Midwest
and Great Lakes) and this event could materialize as a blizzard in
some areas with widespread substantial impacts from Saturday into
early next week.


Weiss



$$

= = =
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FOUS11 KWBC 120807
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
407 AM EDT Thu Mar 12 2026

Valid 12Z Thu Mar 12 2026 - 12Z Sun Mar 15 2026

...Cascades Through The Northern Rockies...=20
Days 1-2...

...Washington Cascades Blizzard today...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with heavy precip and high winds
especially tonight.

Atmospheric river (AR) plunging onshore WA/OR will continue with
high probabilities (>90% chance) of exceeding 250 kg/m/s for IVT
continuing into Friday. This AR has been persistent, and will
maintain a westerly direction through landfall transporting
moisture orthogonally into the WA/OR coasts. This prolonged AR will
bring copious moisture onshore, with pronounced spillover reaching
all the way to the Northern Rockies as reflected by still high
probabilities (>90% chance) for IVT exceeding 250 kg/m/s today and
tonight.

This moisture will be wrung out as heavy precipitation through
orographic enhancement into the Olympics, Cascades, and Northern
Rockies, with additional heavy precipitation reaching the lower
elevations through mid-level isentropic ascent due to WAA. However,
a low pressure moving out of Alberta, Canada and into the Northern
Plains by Thursday aftn will drape a cold front southward, with
this front become elongated west to east causing some additional
upslope and mesoscale ascent, while additionally creating a sharp=20
gradient in snow levels. North of this front, snow levels will
waver between 1500-2500 ft, creating significant impacts at many of
the Cascades and Northern Rockies passes, especially during D1 when precipitation will be the heaviest. Farther south, snow levels will
remain elevated as high as 6000-7000 ft in Oregon, resulting in far
weaker winter related impacts through the period.

The precipitation will likely be nearly continuous across the
terrain, with only as low S/SE trend through Friday evening.
However, by Saturday, the ascent should advect away to the east
while the best moisture shunts to the southeast, bringing an end to
wintry precipitation across the area. Before that happens, periods
of heavy snow combined with strong winds will result in blizzard
conditions across the Olympics, WA Cascades, and parts of the
Northern Rockies near Glacier NP and the Lewis Range. With snow
levels so low, travel across the passes will be extremely impacted
as 1-2+"/hr snowfall combines with strong winds. Where this snow
accumulates most robustly, WPC probabilities are high (>70%) for at
least an additional 24", with locally 3-5 feet of snow expected in
the Cascades and highest Northern Rockies elevations, leading to
continued challenging travel across the passes.=20


...Great Lakes into the Northeast...
Days 1-2...

A fast moving, compact, but intense low pressure will race eastward
near the United States/Canada border from this morning through
Saturday morning, bringing a stripe of heavy snow and strong winds
to parts of the area.

This low will initially develop over the British Columbia province
Wednesday evening, but being to deepen rapidly as it approaches
North Dakota Thursday morning. This low will be driven by a potent
shortwave emerging from the Canadian Rockies and then deepening
into a closed low despite modest amplitude of the feature thanks to
being embedded within pinched westerlies and fast mid-level flow.
As this shortwave deepens, likely reaching peak amplitude 00Z/Fri -
12Z/Fri, it will work in tandem with the LFQ of nearly zonal, but strengthening, jet streak, to produce rapid ventilation aloft to
result in the surface low deepening quickly. This low is likely to
track from western ND to eastern WI on Thursday, and then continue
east, ejecting away from the Maine coast on Saturday morning.

As this low progresses east, especially into the Great Lakes, it
will interact with a moistening column thanks to residual IVT from
an atmospheric river spreading eastward from the Pacific Northwest.
PWs are progged to reach +2 sigma, with this moisture then being
advected cyclonically into the low, reflected by a strengthening
theta-e ridge /TROWAL/ lifting northward into the western Great
Lakes. Impressive deep layer ascent will then couple with
increasing isentropic ascent and 850-700mb fgen (in response to
intensifying WAA) to produce an environment will support heavy snow
rates for which the HREF suggests has a 70-90% chance of exceeding 1"/hr, especially along the Arrowhead and into the U.P. of MI. Although=20
there is still some latitudinal uncertainty as to where the=20
heaviest snow will occur, there is high confidence in a stripe of=20
heavy accumulations from northern MN through northern WI, the U.P.
of MI, and into the northern L.P. of MI. This is reflected by WPC
probabilities that are high (>70%) for at least 6 inches from far
northern MN into much of the U.P. and northern L.P. of MI, with=20
locally more than 12 inches possible across the Iron Ranges of the=20 Arrowhead.

Additionally, impacts will be considerable as these intense
snowfall rates combine with gusty winds that may reach 30-50 mph to
produce near blizzard conditions and dangerous travel. The WSSI-P
indicates a 20-40% chance of at least moderate impacts across the
Upper Midwest/Great Lakes, so the Thursday evening and Friday
morning commutes will likely be extremely challenging.

As this low skirts eastward on Friday into Saturday, it initially
occludes over MI and then pivots rapidly into New England Friday
night. During this time, the most significant ascent beings to wane
as the upper low opens and the best synoptic ascent no longer
overlaps within the LFQ of the accompanying jet streak. Impressive
WAA at 850mb will surge northeast from the Mid-Atlantic states into
the Northeast, helping to expand precipitation further despite a
reduction in available PW (compared to areas farther west). This
will likely still result in a swath of moderate snowfall from
Upstate NY through coastal ME, with again some continued
uncertainty into the latitudinal placement of the heaviest amounts.
The heaviest snow is likely in the upslope regions of the
Adirondacks D2 where WPC probabilities are high (>70%) for at least
6 inches, including across the Tug Hill Plateau, with lesser, but
still significant snowfall of 2-4" expected in the higher terrain
of the Green and White Mountains.


...Central Appalachians & I-95 Corridor...=20
Day 1...

A tricky forecast for snowfall will develop from the Central
Appalachians into the Mid-Atlantic states today. A powerful cold
front will race eastward from the Ohio Valley/Central Appalachians
tonight, to exit the Mid-Atlantic coast by late this afternoon.
Precipitation developing along the front will expand northeast and
become heavy within a plume of PWs above +3 sigma. This will
support primarily heavy rain as the column will be much too warm
for any wintry p-types. However, the intense CAA along and
immediately behind the front will drive tremendous ascent and
rapidly cool the column, aided by dynamic cooling as precipitation
falls from aloft. Cold air chasing moisture is rarely a setup that
supports snowfall, especially after record high-temperatures from Tuesday/Wednesday. However, a potent jet streak will try to
strengthen just as the cold front moves offshore, placing
sufficient deep layer lift atop the front to potentially change
precip over to heavy snow, aided by additional ascent downstream of
the primary southern stream shortwave/PV anomaly opening into the
Mid-Atlantic. This could support snowfall that could be heavy at=20
times thanks to strong omega into the DGZ.=20

The combination of intense lift into the DGZ at the same time as=20
the column cools (with steep lapse rates below 850mb) could support
a changeover to heavy snowfall, at least briefly, from northern NC
through Long Island. The timing of the changeover (afternoon)
combined with the antecedent hostile conditions (for snow
accumulation) will limit most impacts. However, the high-res is in
decent agreement that there will be a changeover to heavy snow with
rates potentially exceeding 1"/hr at times. This will likely not
materialize as 1"/hr accumulation, and any accumulations should be
limited to grassy surfaces as reflected by WPC probabilities that
are generally 10-30% for 1" of snow (higher in the higher terrain). However,
a wide range in WSE plumes suggests the potential for some=20
accumulation, especially along and east of I-95 or across the=20
higher terrain of the Blue Ridge, which could impact travel for the
evening commute as reflected by the WSSI-P supporting at least=20
modest probabilities for minor impacts.


...Northern High Plains through the Upper Midwest...
Day 3...

...Increasing confidence in a major winter storm this weekend...

The next in a series of shortwaves embedded within rapid flow
across the northern tier will move onshore the British Columbia
coast Friday and then advect rapidly southeast while deepening. The
core of this shortwave and its associated vorticity is expected to
dive across the Northern Rockies Saturday night and then reach the
central High Plains by Saturday night/Sunday morning. This
deepening trough across the High Plains will move across a residual
baroclinic gradient draped from the Northern Rockies into the
Central Plains, to help drive surface cyclogenesis in the lee of
the Rockies. This low is then likely to rapidly intensify as it=20
tracks northeast into Sunday, aided by coupling of upper level jet
streaks. Although there continues to be spread among the various
ensemble clusters, there is high confidence in this low developing
and reaching the Central Plains by the end of the forecast period.

This low will develop within impressive moisture, both in response
to persistent IVT spreading Pacific moisture onshore and across the
West, but also in response to an expanding theta-e ridge emerging
from the Gulf downstream of the amplifying trough axis. As this low
deepens, it will wrap this moisture northward through intensifying
isentropic ascent/WAA, leading to a large swath of heavy snow.=20

This heavy snow may begin as early as Friday across the northern=20
High Plains in response to impressive fgen driven both by the
low-level front and 700mb WAA and the response to the peripheral=20
RRQ of the zonally oriented jet streak aloft. It is this jet
streak overlapping the strengthening 700mb WAA, as it moves=20
eastward, which will allow snow to expand in a narrow corridor=20
across the High Plains into the Upper Midwest through Saturday
morning, and in some places there may be two rounds of moderate to
heavy snow. However, the most significant snowfall is expected to
begin Saturday night and then continue beyond this forecast period
from the Northern Plains into the Great Lakes. While it remains a
bit too early for specific forecast amounts, 2-day WPC
probabilities for at least 8" of snow are above 70% across the High
Plains of MT, and 30-70% for parts of SD and MN, and snowfall=20
rates above 1"/hr appear probable due to a synoptic evolution that=20
suggests impressive banding is likely.

These snowfall rates combined with an intense pressure gradient due
to a strong high positioned just to the northwest, will likely
cause significant blowing and drifting of snowfall, along with
limited visibility. WSSI-P is already projecting 70+% probability=20
for at least moderate impacts (mostly on D4 into the Upper Midwest=20
and Great Lakes) and this event could materialize as a blizzard in=20
some areas with widespread substantial impacts from Saturday into=20
early next week.

Winter storm key messages have been initiated for this event, and
are linked below (Key Message 1).


Weiss



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!_l7_SIF4iMRgLCJLePHWPudv8GP3NFvmHymMtUBheLFyN= D3L4Bl8L4e3qb_iwLvBLK4Meuj_FIJYeuSYOFj4hqjZXiA$=20



$$

=3D =3D =3D
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--- SBBSecho 3.28-Linux
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FOUS11 KWBC 121939
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
339 PM EDT Thu Mar 12 2026

Valid 00Z Fri Mar 13 2026 - 00Z Mon Mar 16 2026

...Cascades Through The Northern Rockies...=20
Days 1-2...

...Washington Cascades Major Winter Storm through Friday...

Active winter weather continues across the WA Cascades and northern
Rockies through Friday night with heavy precip and high winds
especially tonight.

Atmospheric river (AR) plunging onshore WA/OR will continue with
high probabilities (>90% chance) of exceeding 250 kg/m/s for IVT
continuing into Friday. This AR has been persistent, and will
maintain a westerly direction through landfall transporting
moisture orthogonally into the WA/OR coasts. This prolonged AR will
bring copious moisture onshore, with pronounced spillover reaching
all the way to the Northern Rockies as reflected by still high
probabilities (>90% chance) for IVT exceeding 250 kg/m/s today and
tonight.

This moisture will be wrung out as heavy precipitation through
orographic enhancement into the Olympics, Cascades, and Northern
Rockies, with additional heavy precipitation reaching the lower
elevations through mid-level isentropic ascent due to WAA. However,
a low pressure moving out of Alberta, Canada and into the Northern
Plains by Thursday aftn will drape a cold front southward, with
this front become elongated west to east causing some additional
upslope and mesoscale ascent, while additionally creating a sharp=20
gradient in snow levels. North of this front, snow levels will
waver between 1500-2500 ft, creating significant impacts at many of
the Cascades and Northern Rockies passes, especially during D1 when precipitation will be the heaviest. Farther south, snow levels will
remain elevated as high as 6000-7000 ft in Oregon, resulting in far
weaker winter related impacts through the period.

The precipitation will likely be nearly continuous across the
terrain, with only as low S/SE trend through Friday evening.
However, by Saturday, the ascent should advect away to the east
while the best moisture shunts to the southeast, bringing an end to
wintry precipitation across the area. Before that happens, periods
of heavy snow combined with strong winds will result in blizzard
conditions across the Olympics, WA Cascades, and parts of the
Northern Rockies near Glacier NP and the Lewis Range. With snow
levels so low, travel across the passes will be extremely impacted
as 1-2+"/hr snowfall combines with strong winds. Where this snow
accumulates most robustly, WPC probabilities are high (>70%) for at
least an additional 24", with locally 3-5 feet of snow expected in
the Cascades and highest Northern Rockies elevations, leading to
continued challenging travel across the passes.=20


...Great Lakes into the Northeast...
Days 1-2...

A fast moving, compact, but intense low pressure will race eastward
near the United States/Canada border from this morning through
Saturday morning, bringing a stripe of heavy snow and strong winds
to parts of the area.

This low will initially develop over the British Columbia province
Wednesday evening, but being to deepen rapidly as it approaches
North Dakota Thursday morning. This low will be driven by a potent
shortwave emerging from the Canadian Rockies and then deepening
into a closed low despite modest amplitude of the feature thanks to
being embedded within pinched westerlies and fast mid-level flow.
As this shortwave deepens, likely reaching peak amplitude 00Z/Fri -
12Z/Fri, it will work in tandem with the LFQ of nearly zonal, but strengthening, jet streak, to produce rapid ventilation aloft to
result in the surface low deepening quickly. This low is likely to
track from western ND to eastern WI on Thursday, and then continue
east, ejecting away from the Maine coast on Saturday morning.

As this low progresses east, especially into the Great Lakes, it
will interact with a moistening column thanks to residual IVT from
an atmospheric river spreading eastward from the Pacific Northwest.
PWs are progged to reach +2 sigma, with this moisture then being
advected cyclonically into the low, reflected by a strengthening
theta-e ridge /TROWAL/ lifting northward into the western Great
Lakes. Impressive deep layer ascent will then couple with
increasing isentropic ascent and 850-700mb fgen (in response to
intensifying WAA) to produce an environment will support heavy snow
rates for which the HREF suggests has a 70-90% chance of exceeding 1"/hr, especially along the Arrowhead and into the U.P. of MI. Although=20
there is still some latitudinal uncertainty as to where the=20
heaviest snow will occur, there is high confidence in a stripe of=20
heavy accumulations from northern MN through northern WI, the U.P.
of MI, and into the northern L.P. of MI. This is reflected by WPC
probabilities that are high (>70%) for at least 6 inches from far
northern MN into much of the U.P. and northern L.P. of MI, with=20
locally more than 12 inches possible across the Iron Ranges of the=20 Arrowhead.

Additionally, impacts will be considerable as these intense
snowfall rates combine with gusty winds that may reach 30-50 mph to
produce near blizzard conditions and dangerous travel. The WSSI-P
indicates a 20-40% chance of at least moderate impacts across the
Upper Midwest/Great Lakes, so the Thursday evening and Friday
morning commutes will likely be extremely challenging.

As this low skirts eastward on Friday into Saturday, it initially
occludes over MI and then pivots rapidly into New England Friday
night. During this time, the most significant ascent begins to=20
wane as the upper low opens and the best synoptic ascent no longer=20
overlaps within the LFQ of the accompanying jet streak. Impressive=20
WAA at 850mb will surge northeast from the Mid-Atlantic states into
the Northeast, helping to expand precipitation further despite a=20
reduction in available PW (compared to areas farther west). This=20
will likely still result in a swath of moderate snowfall from=20
Upstate NY through coastal ME, with again some continued=20
uncertainty into the latitudinal placement of the heaviest amounts.
The heaviest snow is likely in the upslope regions of the=20
Adirondacks D2 where WPC probabilities are high (>70%) for at least
6 inches, including across the Tug Hill Plateau, with lesser, but=20
still significant snowfall of 2-4" expected in the higher terrain=20
of the Green and White Mountains.


...Northern High Plains through the Upper Midwest...
Days 3-3.5...

...Increasing confidence for a major winter storm this weekend...

The next in a series of shortwaves embedded within rapid flow
across the northern tier will move onshore the British Columbia
coast Friday and then advect rapidly southeast while deepening. The
core of this shortwave and its associated vorticity is expected to
dive across the Northern Rockies Saturday night and then reach the
central High Plains by Saturday night/Sunday morning. This
deepening trough across the High Plains will move across a residual
baroclinic gradient draped from the Northern Rockies into the
Central Plains, to help drive surface cyclogenesis in the lee of
the Rockies. This low is then likely to rapidly intensify as it=20
tracks northeast into Sunday, aided by coupling of upper level jet
streaks. Although there continues to be some spread among the=20
various ensemble clusters, there is high confidence in this low=20
developing and reaching the upper Great Lakes by the end of the=20
forecast period.

This low will develop within impressive moisture, both in response
to persistent IVT spreading Pacific moisture onshore and across the
West, but also in response to an expanding theta-e ridge emerging
from the Gulf downstream of the amplifying trough axis. As this low
deepens, it will wrap this moisture northward through intensifying
isentropic ascent/WAA, leading to a large swath of heavy snow.=20

This heavy snow may begin as early as Friday across the northern=20
High Plains in response to impressive fgen driven both by the
low-level front and 700mb WAA and the response to the peripheral=20
RRQ of the zonally oriented jet streak aloft. It is this jet
streak overlapping the strengthening 700mb WAA, as it moves=20
eastward, which will allow snow to expand in a narrow corridor=20
across the High Plains into the Upper Midwest through Saturday
morning, and in some places there may be two rounds of moderate to
heavy snow. However, the most significant snowfall is expected to
begin Saturday night and then continue into Monday from the=20
Northern Plains into the upper Great Lakes. While it remains a bit
too early for specific forecast amounts, 3-day NBM probabilities
for the entire storm ending Tuesday include warning level (6") of
snow at the 5th percentile (meaning 95% chance of more than this)
in a swath from the southeast corner of Minnesota through central
Wisconsin and then northeast across much of the northern Mitt and
far western U.P. of Michigan. 2-day WPC probabilities for at least
8" of snow are above 70% across the High Plains of MT, and 30-70%=20
for parts of SD and MN, and snowfall rates above 1"/hr appear=20
probable due to a synoptic evolution that suggests impressive=20
banding is likely.

These snowfall rates combined with an intense pressure gradient due
to a strong high positioned just to the northwest, will likely
cause significant blowing and drifting of snowfall, along with
limited visibility. WSSI-P is already projecting 70+% probability=20
for at least moderate impacts (mostly on D4 into the Upper Midwest=20
and Great Lakes) and this event could materialize as a blizzard in=20
some areas with widespread substantial impacts from Saturday into=20
early next week. The parent low feeding the system will be in an
intensifying phase as the track turns north of east after the
center crosses the Mississippi River Sunday evening. Very heavy
snow and persistent banding will be in place as the upper level
shortwave trough driving the upper level dynamics of the storm
Sunday night becomes negatively tilted, and the RRQ of the rapidly strengthening upper level jet streak curls to a SSE direction, thus
maximizing upper level divergence. Snowfall rates greater than 2
inches per hour are likely in the strongest bands.

Snow efficiency will be a big challenge with this storm. The
combination of it being mid-March, so there's about 12 hours of
daylight for any snow to contend with when accumulating, as well as
increasing wind concerns, especially Sunday into Monday as the
storm continues to intensify. The winds work to break up the
snowflakes, lowering accumulation efficiency. The cold air coming
south behind the storm is quite dry, as usual, so that should work
to prevent there being much snow at very cold temperatures, which
would increase snow liquid ratios.=20

Finally, NBM mean snow totals are over a foot from southwest
Minnesota across all but far northwestern Wisconsin, and all but
southeast Michigan. 2 foot means cover much of central and
northeastern Wisconsin, the northern Mitt, and most of the western
half of the U.P. Thus, this is expected to be a historic and=20
extremely impactful winter storm due to both snowfall amounts and=20
high winds blowing the snow around. Frequent whiteouts are expected
with blizzard conditions certain along the shorelines of Lakes
Michigan and Superior, and likely for many inland areas.=20

Winter storm key messages have been initiated for this event, and
are linked below (Key Message 1).


Wegman/ Weiss




...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!6CPU2QBS2MnpiTUJhZ1xYelk_Nk_YKf1d2MQcOrzFbdBu= eFFwjRZn66OhIHBmQPGlA8NRFhgh5ax3YlGSy_91pPaBug$=20



$$

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FOUS11 KWBC 130729
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
329 AM EDT Fri Mar 13 2026

Valid 12Z Fri Mar 13 2026 - 12Z Mon Mar 16 2026

...Cascades Through The Northern Rockies...=20
Days 1-2...

...Washington Cascades Major Winter Storm continues today...

Impressive atmospheric river (AR) continues one more day with a
plume of IVT with high probabilities (>90%) for exceeding 500
kg/m/s continuing to advect onshore around 45N near the WA/OR
border. This AR has been ongoing for more than a day already, and
will continue one more day before finally sinking southward Friday
aftn. This prolonged fetch of IVT will cause significant spillover
into the Northern Rockies as well as reflected by still significant probabilities for IVT exceeding 250 kg/m/s, so while the most
intense snowfall will continue across the Olympics and Cascades,
the Northern Rockies will also experience heavy snow for at least
one more day.

The nearly zonal direction of this AR will result in exceptional
orographic enhancement as it directs nearly orthogonally into the
Olympics and Cascades, with additional large scale ascent being
produced via isentropic ascent on the WAA within the AR plume and
modest LFQ diffluence as the Pacific jet streak sinks southward. At
the surface, a stationary front will waver in a west-to-east
fashion through tonight before finally sinking southward as a cold
front in response to a shortwave digging out of British Columbia.
This shortwave will also be responsible for weakening and shifting
the narrowing IVT plume southward, with the West-WRF indicating IVT
falling below 250 kg/m/s into northern CA by Saturday morning.

There is high confidence in heavy snow continuing today and tonight
before precipitation slowly wanes on Saturday with much lighter
snow. The more challenging aspect is what will happen with snow
levels across the region. There will be a very sharp gradient in
snow levels from north to south, with the surface front acting as a
demarcation between very low snow levels in the WA Cascades
(1000-2000 ft) and much higher across OR (6000-7000 ft). As the
front digs south in conjunction with the shortwave, snow levels
will crash across OR as well, but with much lighter precipitation
during that transition. This suggests that the heaviest snow (and
most notable impacts) will be across the WA Cascades and Olympics,
with considerable impacts also expected in the Northern Rockies,
and lesser snowfall and impacts expected across the OR Cascades.

This is reflected by WPC probabilities that are high (>70%) for at
least an additional 12 inches in the WA Cascades and parts of the=20
Northern Rockies. At least 4 inches of additional snowfall D1 is=20
expected (>70%) in the Blue Mountains, the higher elevations of NW=20
WY near Yellowstone NP, and the Sawtooth/Salmon River ranges. BY
D2, snowfall persisting across the Cascades wanes rapidly leaving
just light additional accumulations, but heavy snow will continue
across the Wind Rivers, Absarokas, Tetons, Big Horns, and other
neighboring terrain where WPC probabilities predict a high risk

70%) for 8+ inches of snow.

...Great Lakes into the Northeast...
Days 1-2...

Intense but compact low pressure will cross the Great Lakes today
bringing blizzard, and near-blizzard conditions, to many areas.
This low is being driven by a potent shortwave which is progged to
briefly close off near the MN Arrowhead tonight (pre-forecast
period) and then slowly open as it pivots eastward on Friday. This
will result in the occlusion of the accompanying surface low over
MI, leading to a brief slowing of the low before it then picks up
speed and races east into New England Saturday before exiting into
the Canadian Maritimes.

This event will be considerable for the Great Lakes. The
combination of the deep surface low, impressive upper shortwave,
and the LFQ of zonally oriented jet streak arcing from the Pacific
Northwest will drive intense deep layer lift. Within this region of
deep layer omega, impressive mesoscale ascent will aid through fgen
thanks to WAA lifting into a TROWAL, and a deformation axis which
will pivot N/NW of the surface low. Additionally, low-level flow
across Lake Superior from the east will lift orographically into
the Arrowhead/Iron Ranges bringing locally even heavier snow.

The setup is favorable for intense snowfall rates, despite SLRs
that may become fractured due to strong winds leading to blizzard
and near-blizzard conditions. The snow character may be drastically
different in some places too, with WAA leading to a heavier-wet
snow across the L.P. of MI, and more near-climo or fluffier/lighter
snow across the U.P. and into the Arrowhead. Regardless, the HREF
probabilities for 1"/hr snowfall reach above 70-80% in many areas,
with 2+"/hr snowfall rates possible at times thanks to CSI. Where
this snow is most intense and lingers the longest on D1, WPC
probabilities predict a high chance (>70%) of at least 6 inches
(after 12Z this morning) for the Huron Mountains of the U.P. as
well as near the Tip of the Mitt, with lighter accumulations
surrounding these areas.

As the low continues to pivot eastward late D1 into D2, a=20
resurgence of WAA will expand precipitation into New England, and a
secondary low may develop near the coast of ME Saturday morning.
Total forcing for ascent and available moisture will likely be less
than areas upstream (in the Great Lakes), but periods of heavy snow
both within WAA and along an inverted trough/occluded front
upstream from the secondary low pressure will result in areas of
heavy snowfall with rates again potentially reaching 1"/hr. WPC
probabilities across the Northeast are as high as 90% for 4+ inches
in the Tug Hill and southern Adirondacks, with probabilities
reaching 50-70% for the Chautauqua Ridge, and parts of the higher
terrain of VT/NH/ME. A local maxima is also possible along the
coast of ME where onshore flow ahead of the secondary low pressure
advects higher moisture onshore.


...Northern High Plains through the Upper Midwest...
Days 1-3...

...Blizzard likely this weekend with widespread major impacts and
potentially record-breaking snowfall for the Upper Midwest and=20
Great Lakes...

Guidance is consolidating around a rapidly strengthening low which
will develop in the lee of the Rockies Saturday night and then
track northeast through Monday before occluding and then exiting
after the forecast period. While the primary low is going to be the
one that brings the most substantial impacts, this system will, in
reality, driven by two distinct surface lows embedded within the
amplifying mid-level pattern and accompanying coupled jet streaks.

The event really begins today across the High Plains as moisture
streaming onshore within an impressive IVT plume (atmospheric
river) continues to push well inland leading to a surge in
PW/column moisture across Montana. The accompanying upper jet
streak arcing zonally across the region working in tandem with a
surface stationary front will cause snowfall to break out and
spread WNW to ESE across the state. Overall ascent during D1 across
this area appears modest as noted by omega fields and regional
soundings, but the impressive PW anomalies (nearing +2 sigma) will
support periods of moderate snowfall from MT through parts of SD.
The heaviest accumulations are likely in the higher terrain, with
otherwise modest accumulations expected D1. Where the heaviest snow
occurs, generally just east of the Continental Divide, WPC
probabilities are high (>70%) for at least 4 inches of snow for
much of central and southern MT, with locally more than 8 inches
possible in the Little Belt range.

The more significant portion of this event begins Saturday /D2/ as
lee cyclogenesis begins in more impressive fashion east of CO/WY. A
shortwave digging onshore the British Columbia coast Friday night
will begin to amplify as it digs into the Central Rockies Saturday
night. The rapid amplification of this shortwave will drive
impressive height falls downstream, with impressive jet streak
intensification occurring as a result. The overlap of height falls
with this jet development will lead to a rapidly deepening surface
low tracking from CO to IA before 12Z Sunday. As the jet begins to
kink southward, it will continue to produce heavy snow, with an
expansion across MT due to mid-level divergence downstream of the=20 approaching shortwave. At this time the snowfall rates should
become more intense through 00Z/Sun across MT, with additional
snowfall of 4+ inches possible (50-70%) for much of the eastern
half of the state.

After 00Z Sunday is when this event truly becomes a major winter
event with widespread considerable impacts. As the surface low
begins to lift northeast from the Central Plains it will encounter
dual moisture streams, one from the decaying AR pushing east, and=20
a second as the theta-e ridge begins to arc northward on=20
intensifying WAA/southerly flow out of the Gulf. The overlap of=20
robust deep layer ascent with maximizing moisture return will=20
deepen the low substantially, and help expand a considerable=20
precipitation shield, with heavy snow arcing from SD through the=20
Great Lakes by the end of D2, and then slowly pivoting northeast=20
while continuing through D3 as the surface low reaches MI by=20
12Z/Monday.

The synoptic setup is extremely favorable for a classic Midwest
winter storm with widespread intense snowfall. Embedded bands=20
with snowfall rates of 1-3"/hr are expected as reflected by high=20
potential for CSI and even CI in model cross-sections Sunday aftn=20
into Monday which drives intense omega into the TROWAL. Although=20
guidance has trended slightly north tonight, there is high=20
confidence in a laterally translating band of heavy snow from SD=20
into MN Sunday morning, with the environment transiting into one
that matches the conceptual model for a pivoting band over eastern
MN and WI Sunday evening into Monday, It is in this area where the
heaviest snowfall is expected, and potentially record, or near-
record 2-day snowfall is possible from eastern MN through WI and
northern MI. Elsewhere, snowfall rates of 1"/hr or more are still=20
likely at times, just with lesser duration. These snowfall rates=20
combined with gusty winds reaching 50 mph will create blizzard and near-blizzard conditions, with major to extreme impacts progged by
the recent WSSI-P. Even in areas that get lower snow totals, the=20
blowing snow potential will still result in difficult travel, and=20
it is likely that most forms of transportation will be treacherous
at best, and impossible at worst, through the event across a large
area.

2-day WPC probabilities ending 12Z Monday are impressive, and
suggest a high likelihood (>70%) for at least 12 inches from the
Buffalo Ridge eastward through the Twin Cities, across much of WI,
and through all of the U.P. of MI. Within this axis, WPC
probabilities for at least 24" are already above 50%, and some
locations may approach 3 feet before the event winds down Tuesday.
Outside of this axis of heaviest snow, a broad swath of at least 6
inches is likely (>70%) from far western SD through central IA and
northeast into central MI.=20

Finally, on the S/SE side of this snowfall swath, an axis of mixed precipitation is likely, leading to icing accretion from central IA
through southeast WI and into lower MI. The most significant icing
is expected for lower MI where WPC probabilities for at least 0.25"
of ice reach as high as 30-50%.

This storm could result in record snowfall in some places, and=20
with SLRs being slightly below climo, combined with the strong=20
winds, power outages and long-lasting impacts are expected. For=20
these reasons, Winter storm key messages are in effect, and are=20
linked below (Key Message 1).


Weiss


...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!4CUm3VHbp2eO8zz-iqQs-CRbN5QXMmbP5hCf54RPoQaUg= 2fX7_B0T69JzXePtJCSfYDZOvjQXHU45DO1_ExR7dKcoiw$=20



$$

=3D =3D =3D
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--- SBBSecho 3.28-Linux
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FOUS11 KWBC 131821
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
221 PM EDT Fri Mar 13 2026

Valid 12Z Fri Mar 13 2026 - 12Z Mon Mar 16 2026

...Northern High Plains through the Upper Midwest...
Days 1-3...

...Blizzard likely this weekend with widespread major impacts and record-breaking snowfall for portions of the Upper Midwest and=20
Great Lakes...

Guidance is consolidating around a rapidly strengthening low which
will develop in the lee of the Rockies Saturday and then track=20
east through Sunday to the Mississippi Valley, then turn northeast=20
Monday before occluding and then exiting. While the primary low is
going to be the one that brings the most substantial impacts, this
system will, in reality, driven by two distinct surface lows=20
embedded within the amplifying mid-level pattern and accompanying=20
coupled jet streaks.

The event really has already begun across the High Plains of
Montana as moisture streaming onshore within an impressive IVT=20
plume (atmospheric river) continues to push well inland leading to=20
a surge in PW/column moisture across the northern Plains. The=20
accompanying upper jet streak arcing zonally across the region=20
working in tandem with a surface stationary front will cause=20
snowfall to continue to spread ESE-ward. Overall ascent during D1=20
across this area appears modest as noted by omega fields and=20
regional soundings, but the impressive PW anomalies (nearing +2=20
sigma) will support periods of moderate snowfall from MT through=20
parts of SD. The heaviest accumulations are likely in the higher=20
terrain, with otherwise modest accumulations expected D1. Where the
heaviest snow occurs, generally just east of the Continental=20
Divide, WPC probabilities are high (>70%) for at least 4 inches of=20
snow for much of central and southern MT, with locally more than 8=20
inches possible in the Little Belt range.

The more significant portion of this event begins Saturday as lee=20 cyclogenesis begins in more impressive fashion east of CO/WY. A=20
shortwave digging onshore the British Columbia coast tonight will=20
begin to amplify as it digs into the Central Rockies Saturday=20
night. The rapid amplification of this shortwave will drive=20
impressive height falls downstream, with impressive jet streak=20 intensification occurring as a result. The overlap of height falls=20
with this jet development will lead to a rapidly deepening surface=20
low tracking from CO to IA before 12Z Sunday. As the jet begins to=20
kink southward, it will continue to produce heavy snow, with an=20
expansion across MT due to mid-level divergence downstream of the=20 approaching shortwave. At this time the snowfall rates should=20
become more intense through 00Z/Sun across MT, with additional=20
snowfall of 4+ inches possible (50-70%) for much of the eastern=20
half of the state.

After 00Z Sunday is when this event truly becomes a major winter
event with widespread considerable impacts. As the surface low
continues east from the Central Plains it will encounter dual=20
moisture streams, one from the decaying AR pushing east, and a=20
second as the theta-e ridge begins to arc northward on intensifying WAA/southerly flow out of the Gulf. The overlap of robust deep=20
layer ascent with maximizing moisture return will deepen the low=20 substantially, and help expand a considerable precipitation shield,
with heavy snow arcing from SD through the Great Lakes by Sunday
morning, and then slowly pivoting northeast while continuing=20
through D3 as the surface low moves into Ontario by 00Z/Tuesday.

The synoptic setup is extremely favorable for a classic Midwest
winter storm with widespread intense snowfall. Embedded bands=20
with snowfall rates of 1-3"/hr are expected as reflected by high=20
potential for CSI and even CI in model cross-sections Sunday aftn=20
into Monday which drives intense omega into the TROWAL. Although=20
guidance has trended north, there is high confidence in a=20
laterally translating band of heavy snow from SD into MN Sunday=20
morning, with the environment transiting into one that matches the=20 conceptual model for a pivoting band over eastern MN and WI Sunday=20
evening into Monday, It is in this area where the heaviest snowfall
is expected, and potentially record, or near- record 2-day=20
snowfall is possible from eastern MN through WI and northern MI.=20
Elsewhere, snowfall rates of 1"/hr or more are still likely at=20
times, just with lesser duration. These snowfall rates combined=20
with gusty winds reaching up to 60 mph will create blizzard and=20
near- blizzard conditions and whiteouts, with major to extreme=20
impacts progged by the recent WSSI-P. Even in areas that get lower=20
snow totals, the blowing snow potential will still result in=20
difficult travel, and it is likely that most forms of=20
transportation will be treacherous at best, and impossible at=20
worst, through the event across a large area from Montana to
Michigan, and everywhere in between.

2-day WPC probabilities ending 12Z Monday are impressive, and
suggest a high likelihood (>70%) for at least 12 inches from the
Buffalo Ridge eastward through the Twin Cities, across much of WI,
and through all of the U.P. of MI. Within this axis, WPC
probabilities for at least 24" are already above 50%, and some
locations may approach 3 feet before the event winds down Tuesday.
Outside of this axis of heaviest snow, a broad swath of at least 6
inches is likely (>70%) from far western SD through central IA and
northeast into central MI. Similarly impressive, the 07Z NBM 5%
probabilities (meaning a 95% chance of seeing more), show amounts
over a foot from Central Wisconsin around Wausau east to north of
Green Bay, along the north shore of Lake Michigan over to the=20
Straits of Mackinac.

Finally, on the S/SE side of this snowfall swath, an axis of mixed precipitation is likely, leading to icing accretion from central IA
through southeast WI and into lower MI. The most significant icing
is expected for lower MI where WPC probabilities for at least 0.25"
of ice are between 30-50%.

This storm could result in record snowfall in some places, and=20
with SLRs being slightly below climo, combined with the strong=20
winds, power outages and long-lasting impacts are expected. For=20
these reasons, Winter storm key messages are in effect, and are=20
linked below (Key Message 1).


...Cascades Through The Northern Rockies...=20
Day 1...

...Washington Cascades Major Winter Storm continues today...

An atmospheric river (AR) will wane tonight as an area of IVT with
around 500 kg/m/s continues to advect inland into the Pacific
Northwest and weakens. This AR will sink south into Oregon and
weaken overnight. Associated moisture already inland over the=20
Northern Rockies will continue the heavy snow into tonight,
tapering off from west to east.

There is high confidence in heavy snow tonight across the Northern
Rockies before precipitation wanes on Saturday with much lighter=20
snow. The more challenging aspect is what will happen with snow=20
levels across the region. As a surface cold front digs south in=20
conjunction with an upper level shortwave, snow levels will crash=20
across the Oregon Cascades and Idaho Panhandle, but with much=20
lighter precipitation during that transition in Oregon. In Idaho
and points south and east, the moisture will be slower to exit (as
there will be more of it as remnants of the A.R. This suggests=20
that considerable impacts will continue at the higher elevations of
the Northern Rockies, with lesser snowfall and impacts expected=20
across the Oregon Cascades.

This is reflected by WPC probabilities that show at least 4 inches
of additional snowfall D1 in the Blue Mountains, the Bitterroots,=20
the higher elevations of NW WY near Yellowstone NP, and the=20
Sawtooth/Salmon River ranges. By Saturday, snowfall persisting=20
across the Cascades wanes rapidly leaving just light additional=20 accumulations, but heavy snow will continue across the Wind Rivers,
Absarokas, Tetons, Big Horns, and other neighboring terrain where=20
WPC probabilities predict a high risk (>70%) for 8+ inches of snow.


...Great Lakes into the Northeast...
Day 1...

Intense but compact low pressure will continue crossing the Great=20
Lakes into the Northeast tonight and Saturday, bringing blizzard=20
and near-blizzard conditions to many areas. This low is being=20
driven by a potent but progressive shortwave which is progged to=20
continue driving northeast off the coast of Maine by Saturday
afternoon. The accompanying surface low over MI will picks up=20
speed and race east into New England Saturday before exiting into=20
the Canadian Maritimes.

As the low moves into the Northeast tonight, resurgence of WAA=20
will expand precipitation into New England, and a secondary low may
develop near the coast of ME Saturday morning. Total forcing for=20
ascent and available moisture will likely be less than areas=20
upstream (in the Great Lakes), but periods of heavy snow both=20
within WAA and along an inverted trough/occluded front upstream=20
from the secondary low pressure will result in areas of heavy=20
snowfall with rates again potentially reaching 1"/hr. WPC=20
probabilities across the Northeast are as high as 80% for 4+ inches
in the Tug Hill and southern Adirondacks, with probabilities=20
reaching 40-60% for the Chautauqua Ridge, and parts of the higher=20
terrain of VT/NH/ME. A local maxima is also possible along the=20
coast and interior mountains of ME where onshore flow ahead of the
secondary low pressure advects higher moisture onshore.

Wegman/Weiss


...Winter Storm Key Messages are in effect for the blizzard into
the upper Midwest and Great Lakes this weekend through Monday.=20
Please see current Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!_NSB2DTD1F6imMymt-Wtj7XgWd7Pbh0hsQzO2XVi3KNqk= 7rI7-GBiAMUd83G1GtCUJp3CRKMXwQzEqolYjJXAQXfpe4$=20



$$

=3D =3D =3D
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FOUS11 KWBC 140728
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
328 AM EDT Sat Mar 14 2026

Valid 12Z Sat Mar 14 2026 - 12Z Tue Mar 17 2026

...Northern High Plains through the Great Lakes...=20
Days 1-3...

...Blizzard likely this weekend with widespread major impacts and record-breaking snowfall for portions of the Upper Midwest and=20
Great Lakes...

Confidence continues to be high in a widespread major winter storm
from the Northern Plains through the Upper Midwest and Great Lakes
as a lee surface low lifts northeast and rapidly deepens into an
increasingly moist column. While it is this lee cyclone that will
be responsible for the most significant impacts, this event is
really two-pronged with the first event already ongoing across the
Northern High Plains.

Across the High Plains of Montana, moisture continues to stream
onshore within an impressive IVT plume (atmospheric river)=20
pushing well inland leading to a surge in PW/column moisture=20
across the northern Plains. The accompanying upper jet streak=20
arcing zonally across the region working in tandem with a surface=20
stationary front will cause snowfall to continue to spread ESE-=20
ward. Overall ascent during D1 across this area appears modest as=20
noted by omega fields and regional soundings, but the impressive PW
anomalies (nearing +2 sigma) will support periods of moderate=20
snowfall from MT through parts of SD. The heaviest accumulations=20
are likely in the higher terrain, with lower accumulations expected
elsewhere across the High Plains today. Where the heaviest snow=20
occurs, generally just east of the Continental Divide, WPC
probabilities are high (>70%) for at least an additional 4" of
snowfall through tonight, with more than 8" possible in the higher
elevations around the Little Belts.

The more significant portion of this event begins this afternoon=20
as lee cyclogenesis begins in more impressive fashion east of=20
CO/WY. A shortwave digging onshore the British Columbia coast=20
tonight will begin to amplify as it digs into the Central Rockies=20
Saturday night. The rapid amplification of this shortwave will=20
drive impressive height falls downstream, with impressive jet=20
streak intensification occurring as a result. The overlap of height
falls with this jet development will lead to a rapidly deepening=20
surface low tracking from CO to IA before 12Z Sunday.=20

After 00Z Sunday is when this event truly becomes a major winter
event with widespread considerable impacts. As the surface low
continues east from the Central Plains it will encounter dual=20
moisture streams, one from the decaying AR pushing east, and a=20
second as the theta-e ridge begins to arc northward on intensifying WAA/southerly flow out of the Gulf. The overlap of robust deep=20
layer ascent with maximizing moisture return will deepen the low=20 substantially, and help expand a considerable precipitation shield,
with heavy snow arcing from SD through the Great Lakes by Sunday
morning, and then slowly pivoting northeast while continuing=20
through D3 as the surface low moves into Ontario by 00Z/Tuesday.

The synoptic setup is extremely favorable for a classic Midwest
winter storm with widespread intense snowfall. Embedded bands=20
with snowfall rates of 1-3"/hr are expected as reflected by high=20
potential for CSI and even CI in model cross-sections Sunday aftn=20
into Monday which drives intense omega into the TROWAL. Although=20
guidance has continued to trend north, there is high confidence in
a laterally translating band of heavy snow from SD into MN Sunday=20
morning, with the environment transiting into one that matches the=20 conceptual model for a pivoting band over eastern MN and WI Sunday=20
evening into Monday, It is in this area where the heaviest snowfall
is expected, and potentially record, or near-record 2-day snowfall
is possible from eastern MN through WI and northern MI. Elsewhere,
snowfall rates of 1"/hr or more are still likely at times, just=20
with lesser duration. These snowfall rates combined with gusty=20
winds reaching up to 60 mph will create blizzard and near-blizzard
conditions and whiteouts, with major to extreme impacts progged by
the recent WSSI-P. Even in areas that get lower snow totals, the=20
blowing snow potential will still result in difficult travel, and=20
it is likely that most forms of transportation will be treacherous=20
at best, and impossible at worst, through the event across a large=20
area from Montana to Michigan, and everywhere in between.

Event-total snowfall is likely to be extreme in some areas. This is
reflected by 72-hr WPC probabilities (ending 12Z Tuesday) that are
high (>70%) for at least 12" from the Coteau des Prairies of SD
eastward through the Twin Cities, across much of north-central WI,
and the entirety of the U.P. of MI. Where snowfall is most
prolific, likely in northern WI and the U.P of MI, WPC
probabilities indicate a 70-90+% chance of at least 24", and
localized totals of 3-4 feet are possible before this event ends.=20
This could result in record snowfall in some places, and with SLRs
being slightly below climo, combined with the strong winds, power=20
outages and long-lasting impacts are expected. For these reasons,=20
Winter storm key messages are in effect, and are linked below (Key=20
Message 1).

On the S/SE side of this snowfall swath, an axis of mixed=20
precipitation is likely, leading to icing accretion from central IA
through southeast WI and into lower MI. The most significant icing
is expected for lower MI where WPC probabilities for at least=20
0.25" of ice have climbed to over 50%, and the axis of higher
probabilities for at least 0.10" of ice have extended back into SE
WI.

As this system finally departs late D3, pronounced CAA on NW flow
in its wake could result in some lake effect snow in the favored NW
snow belts downstream of all the Great Lakes. WPC probabilities are
moderate (50%) for at least 4" of snow from LES in SW MI, as well
as along the Chautauqua Ridge and into the Tug Hill Plateau.
Additional heavy snow will occur near Marquette, MI as well, adding
onto the extreme snowfall event there the next few days.


...Cascades, Northern & Central Rockies...=20
Day 1...

The persistent atmospheric river (AR) which has plagued the Pacific
and Interior Northwest the past several days will finally come to=20
an end Saturday as the IVT plume weakens and sinks southward into
CA. This will be the result of the intensifying shortwave diving
out of British Columbia and pushing a surface low pressure east,
which will then trail its accompanying cold front southward into
the Great Basin. Much of of the available moisture will be focused
ahead of this front, so as the front digs south, the moisture will
follow, bringing a slow end to this impressive event. Strong
ascent will continue, at least the first half of the period, into
the Northern Rockies, with ascent expanding into the Central
Rockies as well, and this is where the heaviest snowfall is
expected before everything shifts into the middle of the country by
D2. Additional snowfall in the Cascades is expected to be minimal,
but WPC probabilities are high (>70%) for at least 6 additional
inches in the Absarokas, Tetons, and Wind Rivers, with locally more
than 12 inches possible in the higher elevations.


...Northeast...=20
Day 1...

The intense and compact low pressure over the Great Lakes tonight
will eject eastward with secondary cyclogenesis expected along the
coast of Maine Saturday morning. Although this low will become=20
dominant as it pivots into the Canadian Maritimes, an elongated=20
inverted trough extending west from this low will maintain ascent=20
across the Northeast much of Saturday.

Continued impressive WAA/theta-e advection into ME will manifest as
periods of heavy snow across that state, especially just northeast
of the surface low and up along the eastern half of the state.=20
This is where the heaviest snow rates are expected, and may exceed=20
1"/hr as suggested by HREF probabilities surpassing 70% across=20
eastern Maine. Here, WPC probabilities indicate a 50-90% chance of
4+ inches of snow today.
=20
Farther west, NW flow along and behind the residual inverted trough
will leave periods of light to moderate snow across the interior=20
northeast, with local snowfall maxima occurring in favored upslope=20
terrain and across the Tug Hill Plateau where some lake enhancement
off Lake Ontario is expected. Snowfall inland may be less than
along the coast, but WPC probabilities indicate around a 70% chance
of 4+" of snow, highest across the Tug Hill Plateau and Green
Mountains of VT, before the system exits and snow ends by Sunday=20
morning.


Weiss



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!7M5ro4GT31sY3zKNuesvKLtIgiKZkjMEGn_kmMJwtIprZ= a6Uy7J48cciO8XAeFRYymT66kYFHU9djMdFC8k1wQNJfvE$=20



$$

=3D =3D =3D
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--- SBBSecho 3.28-Linux
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FOUS11 KWBC 141948
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
348 PM EDT Sat Mar 14 2026

Valid 00Z Sun Mar 15 2026 - 00Z Wed Mar 18 2026

...Northern High Plains through the Great Lakes...=20
Days 1-3...

...Blizzard expected this weekend with widespread major impacts=20
and record-breaking snowfall for portions of the Upper Midwest and=20
Great Lakes...

Confidence continues to be high for a widespread major winter=20
storm from the Northern Plains through the Upper Midwest and Great=20
Lakes as a lee surface low lifts northeast and rapidly deepens into
an increasingly moist column. While it is this lee cyclone that=20
will be responsible for the most significant impacts, this event is
really two-pronged with the first event already ongoing across the
Northern High Plains.

The more significant portion of this event has begun this=20
afternoon as lee cyclogenesis begins in more impressive fashion=20
east of CO/WY. A digging shortwave over Idaho, Montana, and=20
Wyoming will drive impressive height falls downstream, with=20
impressive jet streak intensification occurring as a result. The=20
overlap of height falls with this jet development will lead to a=20
rapidly deepening surface low tracking from CO to IA before 12Z=20
Sunday.=20

After 00Z Sunday is when this event truly becomes a major winter
event with widespread considerable impacts. As the surface low
continues east from the Central Plains it will encounter dual=20
moisture streams, one from the decaying AR pushing east, and a=20
second as the theta-e ridge begins to arc northward on intensifying WAA/southerly flow out of the Gulf. The overlap of robust deep=20
layer ascent with maximizing moisture return will deepen the low=20 substantially, and help expand a considerable precipitation shield,
with heavy snow arcing from SD through the Great Lakes by Sunday
morning, and then slowly pivoting northeast while continuing=20
through D3 as the surface low moves into Ontario by 00Z/Tuesday.

The synoptic setup is extremely favorable for a classic Midwest
winter storm with widespread intense snowfall. Embedded bands=20
with snowfall rates of 1-3"/hr are expected as reflected by high=20
potential for CSI and even CI in model cross-sections Sunday aftn=20
into Monday which drives intense omega into the TROWAL. Although=20
guidance has continued to trend north, there is high confidence in
a laterally translating band of heavy snow from SD into MN Sunday=20
morning, with the environment transiting into one that matches the=20 conceptual model for a pivoting band over eastern MN and WI Sunday=20
evening into Monday, It is in this area where the heaviest snowfall
is expected, and potentially record, or near-record 2-day snowfall
is possible from eastern MN through WI and northern MI. Elsewhere,
snowfall rates of 1"/hr or more are still likely at times, just=20
with lesser duration. These snowfall rates combined with gusty=20
winds reaching up to 60 mph will create blizzard and near-blizzard
conditions and whiteouts, with major to extreme impacts progged by
the recent WSSI-P. Even in areas that get lower snow totals, the=20
blowing snow potential will still result in difficult travel, and=20
it is likely that most forms of transportation will be treacherous=20
at best, and impossible at worst, through the event across a large=20
area from Montana to Michigan, and everywhere in between.

Event-total snowfall is likely to be extreme in some areas. This is
reflected by 72-hr WPC probabilities (ending 12Z Tuesday) that are
high (>70%) for at least 12" from the Coteau des Prairies of SD
eastward through the Twin Cities, across much of north-central WI,
and the entirety of the U.P. of MI. Where snowfall is most
prolific, likely in northern WI and the U.P of MI, WPC
probabilities indicate a 70-90+% chance of at least 24", and
localized totals of 3-4 feet are possible before this event ends.=20
This could result in record snowfall in some places, and with SLRs
being slightly below climo, combined with the strong winds, power=20
outages and long-lasting impacts are expected. For these reasons,=20
Winter storm key messages are in effect, and are linked below (Key=20
Message 1).

After 00Z Tuesday, snowfall rates will be waning rapidly in direct
association with the storm, transitioning more and more to lake-
effect snows downwind of all of the lakes. Pronounced CAA on NW=20
flow in its wake could result in some lake effect snow in the=20
favored NW snow belts downstream of all the Great Lakes. WPC=20
probabilities are moderate (50%) for at least 4" of snow from LES=20
in SW MI, as well as along the Chautauqua Ridge and into the Tug=20
Hill Plateau. Additional heavy snow will occur near Marquette, MI=20
as well, adding onto the extreme snowfall event there the next few=20
days. The lake- effect will continue into Tuesday morning before=20
largely dissipating.

On the S/SE side of this snowfall swath, an axis of mixed=20
precipitation is likely, leading to icing accretion from central IA
through southeast WI and into lower MI. The most significant icing
is expected for lower MI where WPC probabilities for at least=20
0.25" of ice have climbed to near 60%, and the axis of higher=20
probabilities for at least 0.10" of ice have extended back into SE=20
MN.

Wegman/Weiss


...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!7bG1910CLlgLJuzDPd_Vczrgw-IRTElc1yUV_8uBMMFVE= vbn7GQcCSQee7usdL_U3DMmDf_kaBI_viSxwjX0jWTvFfk$=20



$$

=3D =3D =3D
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--- SBBSecho 3.28-Linux
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FOUS11 KWBC 150801
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
401 AM EDT Sun Mar 15 2026

Valid 12Z Sun Mar 15 2026 - 12Z Wed Mar 18 2026

...Northern High Plains through the Great Lakes...=20
Days 1-3...

...Blizzard expected this weekend with widespread major impacts=20
and record-breaking snowfall for portions of the Upper Midwest and=20
Great Lakes...

Confidence continues to be high for a widespread major winter=20
storm across the Upper Midwest and Great Lakes as a lee surface=20
low lifts northeast and rapidly deepens into an increasingly moist=20
column. Snowfall from Minnesota through Wisconsin and northern
Michigan, including the U.P, will breach 12" in many locations with
areas of northern WI into the U.P. likely to exceed 24" by the
storms closure.

Current WV satellite and UA analysis indicates a maturing synoptic
evolution with a digging shortwave across WY and an attendant=20
surface low currently analyzed over the western High Plains of=20
Kansas. As the shortwave trough digs further to the southeast, flow
will become increasingly meridional over the Central Plains to=20
Mississippi Valley with the trough axis forecast to tilt neutral
to eventually negative with the 5H height pattern expected to close
off near or over IA by later this evening. Surface low will trek
northeast over the course of Sunday, intensifying slowly as it
migrates towards the southern edge of Lake Michigan by nightfall.
As the upper pattern closes off and takes on the negative trough
orientation, surface low will rapidly intensifying as it begins to
enter into its full maturation phase as the primary heights from
850mb to 500mb become more vertically stacked into Monday morning.
The cyclone will finally reach occlusion phase by Monday afternoon,
but surface low pressure will likely be down into the upper 970s by
this juncture over the western Great Lakes, solidifying its
presence with an all-out blizzard for a large chunk of the Midwest
and Great Lakes region. Moisture convergence occurring during the=20
storms life cycle emanating from the decaying AR pushing east, and
a budding theta-e ridge arcing northward on intensifying=20
WAA/southerly flow out of the Gulf will help provide substantial=20
deep layer moisture poleward, as far north as the western Ontario=20
Province in Canada, a testament to the overall fortitude of this=20 disturbance. The overlap of robust deep layer ascent with=20
maximizing moisture return will deepen the low substantially, and=20
aid in the expansion of a considerable precipitation shield, with=20
heavy snow arcing from SD through the Great Lakes already as of the
pre-dawn hours Sunday. Precip field will slowly pivot northeast=20
while continuing through D2 as the surface low moves into Ontario=20
by 00Z/Tuesday.

Little change in the relevant synoptic details referenced in the=20
last forecast as guidance remains steadfast in all facets of this=20
storms anticipated evolution. The synoptic setup is extremely=20
favorable for a classic Midwest winter storm with widespread=20
intense snowfall. Embedded bands with snowfall rates of 1-3"/hr are
expected as reflected by high potential for CSI and even CI in=20
model cross- sections Sunday aftn into Monday which drives intense=20
omega into the TROWAL. There remains high confidence in a laterally
translating band of heavy snow from SD into MN Sunday morning,=20
with the environment transiting into one that matches the=20
conceptual model for a pivoting band over eastern MN and=20
WI/Michigan U.P. Sunday evening into Monday. It is in this area=20
where the heaviest snowfall is expected, and potentially record, or
near- record 2-day snowfall is possible from eastern MN through WI
and northern MI. Elsewhere, snowfall rates of 1"/hr or more are=20
still likely at times, just with lesser duration. These snowfall=20
rates combined with gusty winds reaching up to 60 mph will create=20
blizzard and near-blizzard conditions and whiteouts, with major to=20
extreme impacts progged by the recent WSSI-P. Even in areas that=20
get lower snow totals, the blowing snow potential will still result
in difficult travel, and it is likely that most forms of=20
transportation will be treacherous at best, and impossible at=20
worst, through the event across a large area from Montana to=20
Michigan, and everywhere in between.

Event-total snowfall is likely to be extreme in some areas. This is
reflected by 72-hr WPC probabilities (ending 12Z Tuesday) that are
high (>70%) for at least 12" from southeast MN to points northeast
through north- central WI, and the entirety of the U.P. of MI.=20
Where snowfall is most prolific, likely in northeastern WI and the
U.P of MI, WPC probabilities indicate a 70-90+% chance of at least
24", and localized totals of 3-4 feet are possible before this=20
event ends with the maxima positioned across the Huron Mountains=20
downwind of Lake Superior. This could result in record snowfall in=20
some places, and with SLRs being near to slightly below climo,=20
combined with the strong winds, power outages and long- lasting=20
impacts are expected. For these reasons, Winter storm key messages=20
are in effect, and are linked below (Key Message 1).

After 00Z Tuesday, snowfall rates will be waning rapidly in direct
association with the storm, transitioning more and more to lake-
effect snows downwind of all of the lakes. Pronounced CAA on NW=20
flow in its wake could result in some lake effect snow in the=20
favored NW snow belts downstream of all the Great Lakes. WPC=20
probabilities are moderate (50%) for at least 4" of snow from LES=20
in SW MI, as well as along the Chautauqua Ridge and into the Tug=20
Hill Plateau. Additional heavy snow will occur near Marquette, MI=20
as well, adding onto the extreme snowfall event there the next few=20
days bring storm and LES combination totals towards the 4-5ft range
by Tuesday afternoon. The lake- effect will continue into Tuesday=20
morning before largely dissipating.

On the S/SE side of this snowfall swath, an axis of mixed=20
precipitation is likely, leading to icing accretion from central IA
through southern WI and into the northern mit in lower MI. The=20
most significant icing is expected for the northern mit of MI=20
where WPC probabilities for at least 0.25" of ice have settled=20
between 40-70%, and the axis of higher probabilities for at least=20
0.10" of ice have extended back into southern WI.


...Central Appalachians...

Powerful cyclone over the Great Lakes will provide a strong cold
front trailing the primary surface low as it migrates eastward
through much of the country east of the Mississippi. Once the cold
front advances beyond the Appalachian front, strong cold air
advection (CAA) regime will transpire with rain changing to snow
for the mountains of western PA down through western MD and the
adjacent WV Highlands. Elevations >2000ft will see some snowfall
with the greatest accums focused over areas >2500ft, a general
climo output for this type of evolution. WPC probabilities for >4"
of snowfall are between 20-40% for the entire Appalachian chain of
western PA down through WV. Maxima of 40-60% is located over the
Canaan Valley down into Snowshoe, WV where some deterministic
output are printing out upwards of 6-8" of high ratio snowfall
post-fropa. Setup and magnitude of the upslope flow is classic for
this scenario allowing for growing confidence in at least minor
impacts for the terrain of the Mid Atlantic.=20

Weiss/Kleebauer



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!5Mz4bRZVZZ9RVDTb1sBqsu4WHXcb-lCcyrgMk_jU8_b5T= PaB831GnEHgCTyaR_6m85bP8GQekWHF3E-8MTlD2oSyFkY$=20



$$

=3D =3D =3D
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FOUS11 KWBC 151805
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
205 PM EDT Sun Mar 15 2026

Valid 00Z Mon Mar 16 2026 - 00Z Thu Mar 19 2026

...Upper Mississippi Valley through the Great Lakes...=20
Days 1-3...

...Historic blizzard ongoing through Monday with widespread major=20
impacts and record-breaking snowfall for portions of the Upper=20
Midwest and Great Lakes...

Confidence continues to be high for a widespread major winter=20
storm across the Upper Midwest and Great Lakes as a lee surface=20
low lifts northeast and rapidly deepens into an increasingly moist=20
column. Snowfall from Minnesota through Wisconsin and northern
Michigan, including the U.P, will breach 12" in many locations with
areas of northern WI into the U.P. likely to reach 2-4 feet of
accumulation through Monday night.

A rapidly developing surface low, currently centered near the Quad
Cities of Iowa/Illinois, is being supported both by a digging=20
upper level trough to its west over Nebraska and Kansas and the=20
RER of a 160 kt jet streak to its north and east. A couple of lines
of showers and storms are moving across Iowa and eastern Illinois,
supported by a southwesterly low level jet, pumping in Gulf=20
moisture and locally increasing both shear and unstable, warm air,
feeding the storms. As the shortwave trough digs further to the=20
southeast, flow will become increasingly meridional over the=20
Central Plains to Mississippi Valley with the trough axis forecast=20
to tilt neutral to eventually negative with the 500 mb height=20
pattern expected to close off near or over IA by later this=20
evening. Meanwhile, a maturing "comma-head" has emerged that is
largely snow from Nebraska through the U.P. and into Ontario. There
have already been reports of snow rates of 4 inches per hour, as
several locations have eclipsed the 20 inch mark for accumulations
into Minnesota and Wisconsin.=20


The surface low center will track east into this evening,=20
intensifying as it then turns northeast towards the Straits of
Mackinac by Monday afternoon. As the upper pattern takes on the=20
negative trough orientation, the surface low will rapidly=20
intensify as it begins to enter into its full maturation phase.=20
The primary heights from 850mb to 500mb become more vertically=20
stacked into Monday morning. The cyclone will finally reach=20
occlusion phase by Monday afternoon, but surface low pressure will=20
likely be down into the upper 970s by this juncture over the=20
western Great Lakes, solidifying its presence with an all-out=20
blizzard for a large chunk of the Midwest and Great Lakes region.=20
A classic comma-shaped storm will develop, with cold conveyor belt
supplying ample Gulf moisture into some unusually cold air for this
time of year on the north side of the storm. Thus, expect multiple
bands of heavy snow to develop, which will likely remain nearly
stationary as they pivot around the northeastward-tracking surface
low. Where these stationary bands remain in place the longest is
where the highest snow totals with this storm will be realized.

There has been little change in the relevant synoptic details=20
referenced in the last forecast as guidance remains steadfast in=20
all facets of this storms anticipated evolution. The synoptic setup
is extremely favorable for a classic Midwest winter storm with=20
widespread intense snowfall. Embedded bands with snowfall rates of=20
1-3"/hr are expected as reflected by high potential for CSI and=20
even CI in model cross- sections Sunday aftn into Monday which=20
drives intense omega into the TROWAL. There remains high confidence
in a pivoting band over eastern MN and WI/Michigan U.P. this=20
evening into Monday. It is in this area where the heaviest snowfall
is expected, and potentially record, or near- record 2-day=20
snowfall is possible from eastern MN through WI and northern MI.=20

Elsewhere, snowfall rates of 1"/hr or more are still likely at=20
times, just with lesser duration. These snowfall rates combined=20
with gusty winds reaching up to 60 mph will create blizzard and=20 near-blizzard conditions and whiteouts, with major to extreme=20
impacts progged by the recent WSSI-P. Even in areas that get lower=20
snow totals, the blowing snow potential will still result in=20
difficult travel, and it is likely that most forms of=20
transportation will be treacherous at best, and impossible at=20
worst, through the event across a large area from Montana to=20
Michigan, and everywhere in between.

Event-total snowfall is likely to be extreme in some areas. This is
reflected by 72-hr WPC probabilities (ending 00Z Wednesday) that=20
are high (>70%) for at least 12" from southeast MN to points=20
northeast through north- central WI, and the entirety of the U.P.=20
of MI. Where snowfall is most prolific, likely in northeastern WI=20
and the U.P of MI, WPC probabilities indicate a 70-90+% chance of=20
at least 24", and localized totals of 3-4 feet are possible before=20
this event ends with the maxima positioned across the Huron=20
Mountains downwind of Lake Superior. This could result in record=20
snowfall in some places, and with SLRs being near to slightly below
climo, combined with the strong winds, power outages and long-=20
lasting impacts are expected. For these reasons, Winter storm key=20
messages are in effect, and are linked below (Key Message 1).

After 00Z Tuesday, snowfall rates will be waning rapidly in direct
association with the storm, transitioning more and more to lake-
effect snows downwind of all of the lakes. Pronounced CAA on NW=20
flow in its wake could result in some lake effect snow in the=20
favored NW snow belts downstream of all the Great Lakes. WPC=20
probabilities are moderate (50%) for at least 4" of snow from LES=20
in SW MI, as well as along the Chautauqua Ridge and into the Tug=20
Hill Plateau. Additional heavy snow will occur near Marquette, MI=20
as well, adding onto the extreme snowfall event there the next few=20
days bring storm and LES combination totals towards the 4-5ft range
by Tuesday afternoon. The lake- effect will continue into Tuesday=20
morning before largely dissipating.

On the S/SE side of this snowfall swath, an axis of mixed=20
precipitation is likely, leading to icing accretion from central IA
through southern WI and into the northern mit in lower MI. The=20
most significant icing is expected for the northern mitt of MI=20
where WPC probabilities for at least 0.25" of ice have settled=20
between 40-70%, and the axis of higher probabilities for at least=20
0.10" of ice have extended back into southern WI.

...Post-storm lake-effect...

Behind the storm, a very cold air mass, characterized by 850 mb
temperatures within a couple degrees on either side of -20C, will
plunge across all of the Great Lakes for the Days 2 and 3 periods
from Monday night through Tuesday night. Widespread multi-bands are
expected along the long axis of all of the upper Great Lakes, while
the lake-effect will eventually congeal into single bands downwind
of the lower lakes, especially Ontario. Fortunately, as far as
lake-effect snowstorms go, this will be relatively short-lived,
with the lake-effect ending on the upper lakes by late in the day
Tuesday and on the lower lakes by Wednesday morning as 850 mb
temperatures warm sufficiently to end the lake-effect. WPC
probabilities for 4 inches of snow are high (>70%) for the
southwest corner of Michigan, the Chautauqua Ridge of far western
New York, and east of Lake Ontario. The Tug Hill region
probabiliites are over 90% for 4 inches of snow.=20


...Central Appalachians...
Day 2...


A powerful cyclone over the Great Lakes will send a strong cold=20
front eastward through much of the country east of the=20
Mississippi. Once the cold front advances beyond the spine of the=20 Appalachians, a strong cold air advection (CAA) regime will=20
transpire with rain changing to snow for the mountains of western=20
PA down through western MD and the adjacent WV Highlands.=20
Elevations >2000ft will see some snowfall with the greatest accums=20
focused over areas >2500ft, a general climo output for this type of
evolution. WPC probabilities for >4" of snowfall are between=20
moderate to high (60-80%) from far western Maryland through WV. The
setup and magnitude of the upslope flow is classic for this=20
scenario allowing for growing confidence in at least minor impacts=20
for the terrain of the Mid Atlantic.=20

Wegman


...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!45USA_IH1VuxZq-iR1wGBLb2UqxgKNGXwDaXY8HsLLdoc= ugqTPlMIEddpP2rq7Lan9MbfZYOMPfUTxvjUyNQxrWTiH0$=20



$$

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FOUS11 KWBC 160704
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
304 AM EDT Mon Mar 16 2026

Valid 12Z Mon Mar 16 2026 - 12Z Thu Mar 19 2026

...Upper Midwest through the Great Lakes...=20
Days 1-3...

...Historic blizzard continues today...

The historic blizzard which has been plaguing the Northern Plains
and Upper Midwest will continue in earnest today across the Great
Lakes. The strong surface low driving this impressive event will
steadily advect northeast today after a brief stall this morning
over Michigan during occlusion, leading to continued heavy snow
from northern IL through the U.P. of MI. The low is expected to
pull away well into Canada by 12Z/Tuesday, bringing a slow end to
the blizzard.

The heaviest additional snowfall is expected from southern WI
through the U.P. of MI where snowfall rates above 1"/hr may (60-80%
chance) continue through evening, with the heaviest snowfall
expected in the higher terrain of the U.P. near the Huron
Mountains. The most widespread heavy synoptic snow will wane after
00Z/Tuesday, but before this occurs, the combination of these=20
intense snowfall rates and gusty winds of up to 50 mph will
continue blizzard conditions. The heaviest snowfall swath D1 is=20
likely within the impressive deformation axis which will be
pivoting west of the surface low as it lifts north, and this
deformation is progged to dig as far south as IL/IA Monday morning.
This will bring periods of heavy snow and gusty winds with near-
blizzard conditions even south of the heaviest snow. However,
WPC probabilities indicate the heaviest snow is likely for northern
WI, including the Door Peninsula, into the U.P. of MI where they
reach 50-90% for an additional 6+ inches of snow today, with
locally more than 12 inches possible across the U.P. thanks to lake
effect snow contribution (more on that below).

The ongoing key messages for this historic blizzard remain, and are
linked below (Key Message 1).

As the low pulls away late D1 into D2, the heavy synoptic snow will
draw to an end, but impressive NW winds and CAA in its wake will
bring a period of widespread lake effect snow (LES) to the Great=20
Lakes. Although the lake temperatures are cold, below +5C, and=20
there is considerable ice cover according to GLERL, 850mb temps=20
crashing to around -20C will create steep lapse rates and=20
impressive inversion heights with pronounced omega into the near-=20
surface DGZ. This should be more than sufficient to support heavy=20
LES, with rates above 1"/hr (30-60% chance). While the duration of
heavy LES may be somewhat limited as winds begin to weaken and veer
as the low pulls away, there is sufficient time for locally heavy
accumulations in the favored NW snow belts. WPC probabilities for
LES are high D1 (>70%) for 4+ inches in the NW L.P. of MI near
Traverse City, the far SW portions of the L.P. of MI, and greater
than 50% along the Chautauqua Ridge and the Tug Hill Plateau. LES
wanes in coverage D2 but persists heavily east of Lake Ontario
where probabilities remain elevated (50-90%) for an additional 4+
inches through Tuesday night.


...Central Appalachians & Mid-Atlantic states...
Days 1-2...

The strong low pressure /blizzard/ over the Great Lakes will
steadily move northeast into Canada today, while the parent upper
trough amplifies into the Tennessee Valley and takes on a negative
tilt. This will push a powerful arctic cold front eastward across
the Ohio Valley, Central Appalachians, and Mid-Atlantic states
today. As this front races east, temperatures will plummet on
strong CAA, while mid and upper level flow remains southerly in
response to the strongly tilted and digging upper trough. This will
likely result in precipitation changing over to snow before ending
in most areas.=20

While most of this snow will just be conversational, in the colder
climates of the higher elevations of the Central Appalachians, this
may result in a two-pronged event consisting of heavy snow. The
first will be directly behind the front as p-type changes rapidly
from rain to snow, leading to a brief period of snowfall rates
exceeding 1"/hr (40-60% chance) from the Central Appalachians=20
through the Laurel Highlands and into the Finger Lakes region of=20
NY. During this time, however, snowfall accumulations will be=20
modest at just a few inches at most. However, in the wake of this=20
front, the increasing CAA on NW flow will drive potent upslope=20
ascent into the Central Appalachians Monday night through Tuesday=20
aftn. Although the column is dry aloft, the DGZ will lower to near=20
the surface, leading to favorable ascent due to the upslope to=20
maximize snow growth. This should cause accumulating snowfall in=20
the higher elevations of WV, where WPC probabilities peak above 50%
for 6+ inches of snowfall.

Finally, as the trailing vorticity maxima and secondary shortwave
embedded within the trough finally kicks east Tuesday aftn/eve,
convective snow showers and isolated snow squalls could develop=20
across this area. Additional snowfall accumulations will be light=20
with any of these convective elements, but briefly heavy snow rates
and gusty winds could cause local travel impacts.


Weiss


...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!-YEUl4DZ-_f4nBc_zlclvHZTEy2Prhp8OA7kp4NGWeHQ-= gEPJE_lo4KVd8ZWt9WZjMW1K3N4Q5A2j5ulJY71QtZO72E$=20



$$

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FOUS11 KWBC 161822
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
222 PM EDT Mon Mar 16 2026

Valid 00Z Tue Mar 17 2026 - 00Z Fri Mar 20 2026

...Great Lakes...
Days 1-2...

...Blizzard conditions to persist through this evening in the
Northern Great Lakes...

As this historic winter storm races north and east into eastern=20
Canada tonight, potent NW winds and CAA in its wake will produce=20
widespread lake effect snow (LES) over the Great Lakes. Although=20
lake temperatures are cold and somewhat ice covered, according to=20
GLERL, 850mb temps crashing to as low as -20C will foster steep=20
lapse rates and sufficiently saturated profiles within the DGZ=20
aloft. The result will be LES snow bands with rates above 1"/hr=20
(40-70% chance) tonight and into Tuesday morning. Winds should=20
begin to lessen on Tuesday as high pressure builds in from the=20
west, but prolonged cyclonic flow will fuel rounds of moderate-to-=20
heavy snow in the favored snow belts east of Lakes Erie and
Ontario. LES bands should finally taper off by Tuesday night.

WPC probabilities for LES are moderate-to-high D1 (50-70) for 4+=20
inches in the northwest portion of Michigan's Mitten near Traverse=20
City, along the eastern U.P., and in the southwest L.P.. Farther=20
east, probabilities around 50% for snowfall >4" are located along=20
the Chautauqua Ridge and the Tug Hill Plateau. The Tug Hill on
south closer to Oswego, NY could see locally heavy totals with
low-to-moderate chances (30-50%) for snowfall totals over 12=20
inches possible.=20


...Central Appalachians & Interior Northeast...
Days 1-2...

A powerful arctic front will race through the Northeast and Mid-
Atlantic by this evening. In wake of this FROPA, temperatures will
plummet due to strong CAA, while mid and upper level flow remains=20
southerly in response to the strongly tilted and digging upper=20
trough. Combined with upslope enhancement, this will cause=20
precipitation to rapidly transition to snow from the Central=20
Appalachians and Laurel Highlands to the Finger Lakes of NY and the Catskills/Adirondacks.

While most of this snow will just be conversational at lower
elevations, in the higher elevations of the Central Appalachians,=20
a two-part event supporting of heavy snow is anticipated. The=20
first will be directly behind the front as p-type changes rapidly=20
from rain to snow, leading to a brief period of snowfall rates=20
surpassing 1"/hr (40-60% chance) from the Central Appalachians=20
through the Laurel Highlands and into the Finger Lakes region of=20
NY. This first round of snowfall accumulations will be modest,
generally in the 1-3" initially. However, behind the front, the=20
increasing CAA via NW flow will foster healthy upslope ascent into
the Central Appalachians tonight through Tuesday. Typically favored
areas along the Potomac Highlands and Alleghenies above 2,000ft
will be favored for long snow durations, and thus higher totals.=20
WPC probabilities peak above 50% for 6+ inches of snowfall.

In addition, as the trailing vorticity maxima and secondary=20
shortwave embedded within the trough over the OH Valley moves east
Tuesday afternoon, convective snow showers and isolated snow=20
squalls could develop across this area. Areas from the southern
tier of NY, western and central PA, and on south to the Central
Appalachians would be the most likely areas to contend with any
potential snow squalls. Additional snowfall accumulations will be=20
light with any of these convective elements, but briefly heavy snow
rates and gusty winds could cause local travel impacts due to rapid
reductions in visibility.


Weiss/Mullinax



...Winter Storm Key Messages are in effect. Please see current=20
Key Messages below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late= stKeyMessage_1.png__;!!DZ3fjg!_PBmGNDDtPkqf99AfBb9zAW0sYahBWciDI3fczJK8meXB= oxjP-bprusGbhxlHvC5KcNZELrZF-Wv5J8glSkQJf207U4$=20



$$

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FOUS11 KWBC 170624
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
224 AM EDT Tue Mar 17 2026

Valid 12Z Tue Mar 17 2026 - 12Z Fri Mar 20 2026

...Great Lakes southeast through the Mid-Atlantic...
Day 1...

Strong low pressure which produced the blizzard over the Upper
Midwest/Western Great Lakes will be well northeast into Canada this
morning, while its trailing arctic cold front will be positioned
just off the Atlantic Seaboard to start the period. Behind this low
and the associated front, strong CAA on NW winds will be widespread
across the Great Lakes, Central Appalachians, and Mid-Atlantic
States, while a lagging but potent upper trough swings through the
Ohio Valley. The overlap of this upper trough and the post-frontal
NW flow will result in 3 areas of moderate to heavy snowfall today.

1) Great Lakes: CAA on the NW cyclonic flow will drop 850mb temps
to as low as -20C (or slightly colder). This cold air moving across
the lakes will lead to very steep lapse rates and rising inversion
depths despite lake surface temperatures that are generally +5C or
less according to GLERL. This will support efficient lake effect
snow (LES) in the favored W/NW snow belts, and although the
duration of any single bands may be modest due to the movement of
the mid- level trough, heavy snow rates in excess of 1"/hr are
possible (30-50%) within any LES bands. The heaviest accumulations
are likely across the Tug Hill Plateau and then down towards
Syracuse, where WPC probabilities are high (>70%) for at least 4
inches of snow, with locally more than 8 inches possible.

2) Central Appalachians: The persistent NW flow will generally
result in a drying column across the area. However, as the mid-
level trough swings overhead, it will briefly provide some
additional synoptic ascent through height falls/PVA, overlapping
favorable upslope flow into the terrain to produce periods of
moderate to heavy snow. The nature of this snow may be more snow
"showery" that continuous, limiting accumulations overall. However,
snowfall rates may at times reach 1"/hr (10-30% chance) leading to
locally as much as 4 inches of snow (10-30% chance) in the higher
terrain of WV and into the Laurel Highlands of PA.

3) Ohio Valley to the Mid-Atlantic: As the mid-level trough swings
overhead this aftn/eve, it will likely encourage some bubbling of
convective snow showers and isolated snow squalls across the
region. Lapse rates become impressively steep beneath this trough,
and there will be just enough moisture to generate numerous
convective snow showers which will move rapidly east through the
evening. The SnSq parameter is high for OH/WV/PA, and lesser due to
drier air farther east. While snow squalls can't be ruled out,
this is more likely to manifest as scattered to numerous convective snow showers across the area. Accumulation from these will be minimal,
but brief heavy snow rates and gusty winds could cause rapid
changes in visibility and hazardous driving later today.


The probability for significant icing across the country is less
than 10%.


Weiss


$$

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FOUS11 KWBC 171830
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
230 PM EDT Tue Mar 17 2026

Valid 00Z Wed Mar 18 2026 - 00Z Sat Mar 21 2026

...Upper Midwest to the Northeast...

The CONUS continues to enter a notably more tranquil pattern
regarding heavy snow following the departure of the historic mid-
March blizzard. Widespread heavy snow (accumulations greater than 4
inches) is not expected across the lower 48 through late Friday.

However, the upper level pattern is forecast to remain amplified,
with a strong ridge anchored over the western U.S., while a broad
trough remains centered over the East. An amplified shortwave
currently moving through the base of this eastern trough will lift
out today, but the overall pattern will persist through the end of
the week.

Tonight into Wednesday, a low-amplitude shortwave sliding through
the northern northern tier will trigger a round of warm advection precipitation. Expect a swath of light snow, with some freezing
rain in spots, to develop from the upper Mississippi Valley to the
western Great Lakes. WPC probabilities indicate minor impacts for
most areas, with snow totals capped at 1-2 inches.

Further downstream, lake effect snows will persist in the lee of
Lake Ontario, with several more inches possible along a narrow
band southeast of the lake before winds back to the south tomorrow.

A more amplified shortwave is forecast to dive into the northern
Great Lakes on Friday. However, accumulations are expected to
light and largely confined to northern Michigan.

The probability for significant icing across the country is less
than 10%.

Pereira

$$

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FOUS11 KWBC 180619
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
219 AM EDT Wed Mar 18 2026

Valid 12Z Wed Mar 18 2026 - 12Z Sat Mar 21 2026

...Upper Midwest to the Northeast...
Days 1-2...

Generally quiet winter weather encompasses the CONUS the next
several days as flat and fast flow keep systems progressive and
weak. Within this regime, multiple weak shortwaves traversing WNW
to ESE from the Northern Plains into the Mid-Atlantic and New
England will bring brief periods of light snow and mixed
sleet/freezing rain. In general, this will produce only minor
impacts and no significant snowfall. However, even light freezing
rain can be problematic to travel, so although WPC probabilities
for even 0.1" of ice are less than 5%, some light freezing rain
above 0.01" is likely (>70%) D1 for Wisconsin and lower Michigan,
and again D2 for far southern Michigan into Indiana/Ohio, which
could create travel difficulties due to icy roads.

Weiss


$$

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FOUS11 KWBC 181910
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
310 PM EDT Wed Mar 18 2026

Valid 00Z Thu Mar 19 2026 - 00Z Sun Mar 22 2026

...Upper Midwest to the Northeast...
Days 1-3...

A quiet pattern with respect to heavy snow and icing will continue,
with widespread heavy snow or significant icing not expected across
the contiguous U.S. through the end of the week.

Precipitation associated with a low-amplitude shortwave sliding
southeast across the Upper Midwest is expected to produce some
minor ice accumulations tonight from northern Wisconsin southeast
into southern Michigan and far northern Indiana.

Meanwhile, a more amplified shortwave to the north will spread
light snow from far northern Michigan to Upstate NY and northern
New England as it swings across southeastern Canada on Thursday.

A second shortwave will amplify over the northern Great Lakes on
Friday and move east across the Northeast on Saturday, bringing
additional light snow accumulations to the same regions. Apart
from some localized heavier amounts in the higher reaches of the
Adirondacks and the northern New England mountains, three-day snow accumulations are expected to top out at only an inch or two for
most of the impacted locations.

Pereira

$$

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FOUS11 KWBC 190611
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
211 AM EDT Thu Mar 19 2026

Valid 12Z Thu Mar 19 2026 - 12Z Sun Mar 22 2026

...Upper Great Lakes to the Northeast...
Days 1-3...

Thanks to a dome of upper-level ridging firmly entrenched over
the West and northerly low-level winds over the Mid-South all but
cutting off Gulf moisture, a quiet pattern with respect to heavy
snow and icing will continue. The lone cases where light snow
accumulations are anticipated are across the Upper Great Lakes and
Northeast as Canadian clipper systems race across the southern
tier of the country and occasional pass through. A clipper over
Ontario will direct a warm front through the Northeast with minor
snowfall totals (generally a coating-2", with local 2-3" in the
Adirondacks and White Mountains) through Thursday. As that system
exits over Atlantic Canada, a more organized clipper will be
tracking towards Lake Superior. Light snow will ensue along the
warm front over the U.P. of MI, Thursday night and into Friday AM,
then race over northern NY and northern New England Friday
afternoon and evening.

There are some hints in AI guidance (EC-AIFS most notably) that the
clipper could strengthen by the time it reaches Downeast Maine
early Saturday morning. This could lead to locally heavier snowfall
in the Greens, Whites, and northern ME on Saturday. At the moment,
WPC probabilities shows low chances (10-30%) chances for snowfall

4" in northern ME with most snowfall generally under 3". But this

will be closely monitored given the generally good performance of
the EC-AIFS for much of the cold season.


The chances for significant icing across the CONUS is less than 10
percent.


Mullinax




$$

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FOUS11 KWBC 191903
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
303 PM EDT Thu Mar 19 2026

Valid 00Z Fri Mar 20 2026 - 00Z Mon Mar 23 2026

...Upper Great Lakes to the Northeast...
Days 1-3...

Ridge/trough upper pattern over the CONUS will continue to bring
northern stream systems through the Great Lakes into the Northeast
with minor to occasionally modest snowfall. A system over southern
Canada this evening will push through the Great Lakes tonight and
into southern/southeastern Ontario tomorrow. WAA-driven snow and
some light icing is likely over the U.P. of Michigan and into
northern Lower Michigan. As the clipper moves into the Northeast
tomorrow afternoon/evening, snow will fall mostly over the higher
elevations (above 1500ft or so) where WPC probabilities for at
least 4" are >50%, with lesser accumulations to the valley floors
(T-2"). Precipitation should end on Saturday morning.

The next system will slip into northern MN and the western Great
Lakes Saturday afternoon/evening. With a southwest-to-northeast
thermal gradient, some icing is possible once again over
northeastern MN, northern WI, and northern Lower Michigan near the
surface warm front. That system may track a bit farther south,
which could bring in at least some light to modest snow to
northeastern MN into the U.P. of Michigan. There, WPC probabilities
for at least 4 inches of snow are >40% Saturday into very early
Sunday. The system will race eastward and bring another swath of
snow to northern NYS into New England Sunday. Through 00Z/Mon, WPC probabilities for an additional 4 inches of snow are >30% over the
higher elevations of the northern Adirondacks into the Green/White
Mountains, but the snow will continue beyond this forecast range.


The chances for significant icing across the CONUS is less than 10
percent.

Fracasso

$$

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FOUS11 KWBC 200701
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
301 AM EDT Fri Mar 20 2026

Valid 12Z Fri Mar 20 2026 - 12Z Mon Mar 23 2026

...Upper Great Lakes to the Northeast...
Days 1-3...

The first in a series of clipper systems will produce periods of
snow across northern New York and northern New England today. Low-
level WAA ahead of the clipper will support periods of snow, even
down to the valley floors in northern New England. However,
snowfall rates and elevation will play critical roles in snowfall accumulations. Most notably, the Adirondacks, Green, and White
Mountains are most favored for >1"/hr snowfall rates. WPC
probabilities depict localized moderate probabilities (40-60%) for
snowfall totals >4" with the peaks of these mountain ranges
(including Mt. Washington) sporting low chances (10-30%) for
snowfall accumulations as high as 6". Otherwise, most elevations
below 1,000ft are likely to see anywhere from a coating to as much
as 3". The WSSI does depict some Minor Impact potential,
particularly in the Adirondacks and bordering the St. Lawrence
River in NY's North Country. Snow will taper off across northern
New England by Friday night.

As this clipper exits to the east Saturday morning, the next
clipper system is already making its way towards the Upper Great
Lakes. There remains a decent amount of model spread in the
amplitude and progression of this clipper, largely because it is
essentially an unorganized cluster of sheared 500mb vort maxima
tracking over the northern Great Lakes and Northeast. There will be
sufficient upper-level ascent thanks to the left-exit region of a
500mb jet streak will accompany the clipper. There is also
agreement on model guidance on healthy 850-700mb WAA via WSWrly
flow that collides with sufficiently cold boundary layer
temperatures over northern NY and the rest of northern New
England. However, guidance is not yet in agreement on where the
strongest 850-700mb FGEN takes shape, and as a result, disagree on
the placement of the QPF axis to the north of the storm track. WPC
Day 3 cluster analysis shows the departing trough over Nova Scotia
and the depth of the primary 500mb shortwave trough over the Upper
Midwest are the most sensitive factors in determining what this
clipper ultimately produces, and because of the notably shorter
wavelengths, confidence in where the heaviest snowfall will occur
is not clear out to Day 3.

So what we do know-- It is late March and elevation matters a ton.
However you slice it across deterministic guidance or
probabilistic guidance, the Adirondacks, Green, Whites, and
Berkshires are most favored for accumulating snowfall. Even as far
west as the MI U.P. and MN Arrowhead, snowfall totals approaching
4" are possible. WPC probabilities show low-to-moderate chances
(30-50%) for snowfall totals >4" in the Hurons of the MI U.P.
between Saturday night and through Sunday. Farther east, the

2,000ft elevations in the Adirondacks, Greens, and Whites sport

moderate chances (40-60%) for snowfall totals >8" on Sunday. Below
1,000ft, probabilities for snowfall amounts >4" are low (10-30%)
with most accumulations less than 4" expected at this time. WPC's
WSSI-P depicts moderate chances (40-60%) for Minor Impacts in the
MN Arrowhead to much of northern MI due to a combination of snow
and ice (WPC probabilities show low-to-moderate chances, or 30-50%,
for ice accumulations of at least one-hundreth of an inch) late
Saturday into early Sunday. Minor probabilities are highest in
northern New England where moderate probabilities (40-60%) are
present throughout the northern Appalachians. In fact, some
localized 40-50% probabilities for Moderate Impacts are shown
across south-central and Downeast Maine.


The chances for significant icing across the CONUS is less than 10
percent.


Mullinax




$$

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FOUS11 KWBC 202018
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
418 PM EDT Fri Mar 20 2026

Valid 00Z Sat Mar 21 2026 - 00Z Tue Mar 24 2026

...Northeast...
Days 1-3...

A clipper will move into the Northeast Saturday night bringing a
swath of accumulating snowfall to Upstate NY into Northern New
England. Still some uncertainty with the exact track of this
system, which will impact where the heaviest swath of QPF is and
where the rain/snow line sets up. The higher elevations are most
favored for higher snowfall totals, but strong WAA should support a
period of moderate to locally heavy precipitation. This should
allow snow even down to the lower elevations of northern New
England, especially Saturday night into early Sunday. Snow ratios
from the NBM are likely too high with this system. While snow
should be coming down at a decent clip for a stretch, the strongest
lift appears to be mainly centered below the DGZ, which should cap
snowfall ratios. Then during the daylight hours the late March sun
will play a role in lowering ratios further. In fact, where snow
is falling at a lighter clip we probably won't see much
accumulation during the daytime, with accumulations focused in
either the highest terrain or where snow is falling at a heavy
enough clip to overcome the marginal temperatures and higher sun
angle.

The latest WPC snowfall probabilities have increased for the
Saturday night to Sunday timeframe. The probability of exceeding 4"
in the 24hr period ending 00z Monday are generally 40-80% from
Upstate NY into central to northern VT/NH and western ME. The
highest probabilities are in the higher terrain, but values of
30-50% even get into the lower elevation areas. The probabilities
of 6" are 30-60%, with 8" exceedance probabilities as high as
30-50% in the White Mountains of NH. These probabilities seem
reasonable, with exact snowfall totals dependent on the specific track
of the system. This is a scenario where the higher terrain has the
highest probabilities (and thus confidence) in seeing greater
snowfall totals, but there is still a lower risk of impactful snow
getting into some of the lower elevations if a snowfall band is
able to move into these areas overnight or early morning and is
heavy enough to overcome the marginal temperatures.

A bit more uncertainty exists on Monday as a coastal low tries to
develop offshore New England. By this time it will be cold enough
over northern New England for snow, but if precipitation intensity
is light then the high sun angle will likely limit accumulation.
However, a broader and/or more intense snow shield would be
capable of producing additional accumulating snowfall. Models have
been fluctuating regarding this low and inland precipitation
extent...although most 12z models shifted lighter with QPF. Even
the AIFS, which has been more consistently on the wetter side of
the QPF spectrum, did back off at 12z. There is still time for this
to change, but the probabilities of impactful snowfall Monday
appear to be decreasing, but still need to continue to monitor.

The chances for significant icing across the CONUS is less than 10
percent.


Chenard


$$

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FOUS11 KWBC 210715
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
315 AM EDT Sat Mar 21 2026

Valid 12Z Sat Mar 21 2026 - 12Z Tue Mar 24 2026

...Northeast...
Days 1-2...

A clipper system will move southeast out of central Canada and into
the Northeast this weekend. Snow on the leading edge of the
precipitation shield will move into upstate New York this evening,
then spread across New England tonight. The snow will be
characterized by warm advection. With a high sun angle and
plentiful warm air over much of the eastern half of the country,
the warm air will move into New York and southern New England,
resulting in a changeover to rain on Sunday over much of upstate
New York and into southern New England. Meanwhile, over most of
northern New England, the predominant precipitation type remains as
snow as the back edge of the precipitation quickly pushes east
across New England.

The southwesterly flow of warm air will be uplifted by the terrain
of the Adirondacks, Green, and White Mountains. Here, the
combination of upslope and cooler temperatures at higher
elevations will support multiple inches of snow. The heaviest snow
will fall between early Sunday morning and Sunday evening. In the
valleys, warmer temperatures, high sun angle, and snow mostly
falling during the day should all work to keep snow totals much
lower than the adjacent mountains, though still reaching into
advisory criteria. Where snow rates remain lighter, accumulations
during the day should be greatly tempered, and largely confined to
grassy areas.

WPC snowfall probabilities for the storm total snow over 4 inches
are high (over 70%) from the northern Adirondacks east across the
northern Greens of Vermont, northern Whites of New Hampshire, and
much of southern Maine. For much of northern New Hampshire and
western Maine, those probabilities are above 90% for 4 inches and
over 70% for 8 inches. As typical with compact storms, the exact
longevity and intensity of any internal heavy snow bands will
dictate where the highest snowfall totals are observed.

By D3/Monday, a secondary coastal low is expected to form south of
Long Island. The precipitation shield will be narrow and focus
across southern New England, where temperatures will be warm enough
for mostly (or entirely) rain. Thus, the chances for impactful
snow on Monday anywhere in the Northeast continue to decrease.

The chances for significant icing across the CONUS is less than 10
percent.


Wegman



$$

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FOUS11 KWBC 211915
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
315 PM EDT Sat Mar 21 2026

Valid 00Z Sun Mar 22 2026 - 00Z Wed Mar 25 2026

...Northeast...
Days 1-2...

A clipper system will track across the Northeast late today through
Sunday with snow spreading into northern New York this evening and
northern New England overnight. While warm advection will be a
principle driver for the developing precipitation, it combined with
the high angle will support a changeover to rain across much of
Upstate New York and southern New England on Sunday. In contrast,
the higher elevations of the Adirondacks and much of northern New
England are expected to remain cold enough for snow to remain the
primary precipitation type before the system exits Sunday night.

Terrain-enchanced lifting along with cooler temperatures will
support heavier snow totals across portions of the Adirondacks,
Green, and White mountains -- with several inches likely, as
indicated by the greater than 50 percent WPC probabilities for
accumulations over 8 inches.

While lesser amounts are more likely across the lower elevations,
guidance indicates that low-to-mid level frontogenesis may help
contribute to banded heavier snowfall rates (0.5-1 in/hr) that may
be sufficient enough to support a swath of heavier totals from
east of the western Maine mountains to Down East Maine on Sunday.
Higher probabilities for amounts over 4 inches have expanded across
this area and are now greater than 70 percent across a broader
area. Additionally, probabilities for totals over 8 inches have
increased in this area also, with some greater than 50 percent
probabilities near the Maine coast.

Pereira

$$

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FOUS11 KWBC 220714
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
314 AM EDT Sun Mar 22 2026

Valid 12Z Sun Mar 22 2026 - 12Z Wed Mar 25 2026

...Northeast...
Days 1-2...

Snow has begun falling across the northern Appalachians and
northern New England this morning as 850-700mb WAA aloft overruns a
boundary layer sufficiently cold enough to support snow. Snowfall
rates around 1"/hr are likely over the Green and White Mountains
this morning, where the combination of heavy rates and elevation
will support accumulating snowfall. Given the snow is unfolding
during the day, and boundary layer temperatures are more marginal
in the valleys, snowfall will be tougher to accumulate but still
cause some minor accumulations in the Champlain Valley and along
coastal Maine today. Snowfall will gradually taper off by Sunday
evening with light snowfall over Downeast Maine still unfolding.
There will still be cases where light snow ensues over northern New
England Sunday night and into Monday morning as a strengthening
500mb trough approaches from the west and low-level easterly flow
directs some Atlantic moisture into the region. Additional light
snow accumulations of a coating to 3 inches are possible through
Monday.

48-hour WPC probabilities show high chances (>70%) for >4" of
snowfall throughout southern Maine, the White and Green Mountains,
and the peaks of the Adirondacks. In the Green and White Mountains,
elevations above 2,000ft are likely to see snowfall totals range
between 8-12", with some localized peaks (such as Mount Washington)
potentially receiving over a foot of snow. The WSSI primarily shows
Minor Impacts (winter driving conditions; use caution) with locally
some Moderate Impacts (hazardous travel conditions) possible,
particularly in passes and complex terrain.


...Washington Cascades & Olympics...
Day 3...

A Pacific storm system will direct a plume of moisture at the
Pacific Northwest Monday night and into Tuesday that leads to
higher elevation snowfall. Snow levels initially starting out
between 4,000-5,000ft Monday night and early Tuesday will drop to
as low as 2,500ft in the Olympics and 3,000ft in the northern WA
Cascades. WPC probabilities show moderate-to-high chances (50-80%)
for snowfall totals >4" above 3,000ft in the Olympics and above
4,000ft in the WA Cascades north of I-90. At this moment,
Snoqualmie and Stevens Passes show low chances (<20%) for
accumulating snowfall >4", but some minor accumulations late
Tuesday into Tuesday night are possible.


The chances for significant ice across the CONUS is less than
10 percent.


Mullinax




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FOUS11 KWBC 221931
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
331 PM EDT Sun Mar 22 2026

Valid 00Z Mon Mar 23 2026 - 00Z Thu Mar 26 2026

...Northern New England...
Day 1...

While the primary precipitation shield associated with a clipper
system crossing the Northeast is forecast to begin moving offshore
this evening, a secondary period of accumulating snow is expected
on Monday. An inverted trough, extending back from the departing
low, is forecast to develop and linger across eastern New England.
This feature will likely act to focus a north-south oriented band
of snow showers that could intensify late Monday as an
intensifying shortwave and associated cold pool aloft pivot into
the region from the west.

Given the added lift and some modest instability, localized heavier
bursts are possible, especially in northern New Hampshire and
western Maine where the inverted trough may align with favorable
upslope flow. WPC probabilities indicate that an additional 2-4
inches are possible with this band, with the highest probabilities
(50-70+ percent) focused over the northern New Hampshire and
western Maine mountains.

...Washington Cascades & Olympics...
Days 2-3...

A deepening storm lifting from the northeastern Pacific into
British Columbia will bring widespread moderate to heavy
precipitation into the region on Tuesday. However, the heaviest
precipitation rates are expected to coincide with relatively high
snow levels through Tuesday afternoon. Consequently, the bulk of
the significant accumulating snow (greater than 8 inches) will
remain above the major passes and confined to the higher peaks of
the Olympics and the northern Cascades.

As the front crosses the region late Tuesday and early Wednesday,
snow levels will begin to plunge toward 3,000 ft, but this cooling
will occur as the deepest moisture begins to shift east. However,
some of passes may see a period of rain changing to snow, impacting
travel.


The chances for significant ice across the CONUS is less than
10 percent.

Pereira

$$

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FOUS11 KWBC 230726
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
326 AM EDT Mon Mar 23 2026

Valid 12Z Mon Mar 23 2026 - 12Z Thu Mar 26 2026

...Northern New England...
Day 1...

An inverted trough, extending back from the departing storm system
responsible for rounds of snow yesterday, will linger across
northern New England today. With sufficient low-level moisture off
the Atlantic and vertical ascent supplied by an approaching
shortwave trough to the west, periods of snow will continue over
the White Mountains. Some light snow is possible below 1,000ft, but
given the snow is occurring during daytime hours, snow will
struggle to accumulate on paved surfaces. WPC probabilities depict moderate-to-high chances (50-70%) for additional snowfall
accumulations >4" in the White Mountains, which included Mount
Washington. Otherwise, any additional snowfall accumulations below
2,000ft are likely to range between a coating-3".


...Washington Cascades & Olympics...
Days 1-3...

A strong and meandering closed upper low in the Gulf of Alaska will
direct a storm system forming on its southern flank at British
Columbia the first half of the week. With the Gulf of Alaska low
slow to move east and low level ridging in place off the southern
CA coast, low-level SWrly flow will supply a narrow corridor of
Pacific moisture into the Pacific Northwest Monday night and
through both Tuesday and into Wednesday. Snow levels will generally
reside above 3,000ft through Tuesday, but a cold frontal passage
and falling 700-500mb heights Tuesday night will cause snow levels
to dip to as low as 2,000ft by Wednesday. Still, the cold air in
wake of the cold frontal passage is not particularly cold, and the
best moisture advection will have already concluded by Wednesday.
This is likely to cause periods of mountain snow on Wednesday in
the Olympics and Cascades to as low as 2,000ft, but rates will not
be overly heavy even through Wednesday night.

WPC probabilities for >4" of snow are moderate-to-high (50-80%) for
elevations above 4,000ft north of I-90. Stevens Pass sports
moderate-to-high chances (50-80%) for snowfall totals >4" through
Wednesday night, while Snoqualmie Pass has moderate chances
(40-60%). Both passes sport low-to-moderate chances (20-40%) for
snowfall totals >8", so some locally hazardous travel conditions
are possible at pass level, but the heavier totals surpassing 8"
will likely be found at higher elevations for this event.


The chances for significant ice across the CONUS is less than
10 percent.


Mullinax




$$

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FOUS11 KWBC 231844
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
244 PM EDT Mon Mar 23 2026

Valid 00Z Tue Mar 24 2026 - 00Z Fri Mar 27 2026

...Northern New England...
Day 1...

Latest surface analysis and RAP surface forecast indicate a defined
inverted trough axis bisecting NH up into neighboring Quebec with
some weak precipitation beginning to develop over far northern NH.
Expectation is for ascent to maximize within the trough axis later
this evening as flow focuses out of the north creating upslope flow
orthogonal to the terrain of the White Mountains leading to a
period of snowfall to develop as environmental conditions favor
frozen hydrometeors. Despite modest PWATs present over Northern New
England, the primary ascent pattern within the trough axis coupled
with upslope flow will generate localized moderate snowfall for
several hours creating a focal point of accumulating snow within
the White Mountains and some of the neighboring valleys. WPC
probabilities depict moderate- to- high chances (50-80%) for
additional snowfall accumulations >4" in the White Mountains, which
included Mount Washington. Otherwise, any additional snowfall
accumulations below 2,000ft are likely to range between a
coating-3".


...Washington Cascades & Olympics...
Days 1-3...

Little has changed from the previous forecast as the synoptic scale
pattern remains persistent within all guidance across the Pacific
Northwest. A strong and meandering closed upper low in the Gulf of
Alaska will direct a storm system forming on its southern flank at
British Columbia the first half of the week. With the Gulf of
Alaska low slow to move east and low level ridging in place off the
southern CA coast, low- level SWrly flow will supply a narrow
corridor of Pacific moisture into the Pacific Northwest later
tonight carrying through both Tuesday and Wednesday. Snow levels
will generally reside above 3,000ft through Tuesday, but a cold
frontal passage and falling 700-500mb heights Tuesday night will
cause snow levels to dip to as low as 2,000ft by Wednesday. Still,
the cold air in wake of the cold frontal passage is not
particularly cold, and the best moisture advection will have
already concluded by Wednesday. This is likely to cause periods of
mountain snow on Wednesday in the Olympics and Cascades to as low
as 2,000ft, but rates will not be overly heavy even through
Wednesday night.

WPC probabilities for >4" of snow are moderate-to-high (50-80%) for
elevations above 4,000ft north of I-90. Stevens Pass sports
moderate-to-high chances (50-90%) for snowfall totals >4" through
Wednesday night, while Snoqualmie Pass has moderate chances
(40-60%). Both passes sport low-to-moderate chances (20-50%) for
snowfall totals >8", so some locally hazardous travel conditions
are possible at pass level, but the heavier totals surpassing 8"
will likely be found at higher elevations for this event.


The chances for significant ice across the CONUS is less than
10 percent.


Mullinax/Kleebauer







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FOUS11 KWBC 240711
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
311 AM EDT Tue Mar 24 2026

Valid 12Z Tue Mar 24 2026 - 12Z Fri Mar 27 2026


...Washington Cascades & Olympics...
Days 1-2...

A strong and meandering closed upper low in the Gulf of Alaska
will direct a storm system forming on its southern flank at British
Columbia the first half of the week. With the Gulf of Alaska low
slow to move east and low level ridging in place off the southern
CA coast, low- level SWrly flow will supply a narrow corridor of
Pacific moisture into the Pacific Northwest today and into Wednesday.
Snow levels will generally reside above 3,000ft today, but a cold
frontal passage and falling 700-500mb heights Tuesday night will
cause snow levels to dip to as low as 2,000ft by Wednesday. Still,
the cold air in wake of the cold frontal passage is not
particularly cold, and the best moisture advection will have
already concluded by Wednesday. This is likely to cause periods of
mountain snow on Wednesday in the Olympics and Cascades to as low
as 2,000ft, but rates will not be overly heavy even through
Wednesday night.

WPC probabilities for >4" of snow are high (>70%) for elevations
above 4,000ft north of I-90. Stevens Pass sports high chances

70%) for snowfall totals >4" through Wednesday night, while

Snoqualmie Pass has moderate chances (50-70%). Stevens Pass poses
the slightly better odds for snowfall totals >8", ranging between
30-50%. Some locally hazardous travel conditions are possible at
pass level, but the heavier totals surpassing 8" will likely be
found at higher and more remote elevations.


...Northern Maine...
Days 2-3...

Starting Wednesday night, sheared lobes of 500mb vorticity racing
over the northern Great Lakes will generate PVA over northern New
England at the same time that low-level SWrly flow results in low-
level WAA and increased moisture content. Weak high pressure over
Quebec and sufficiently cold enough air over Maine will support
periods of snow over northern Maine with some minor icing possible
in central ME. As the first disturbance races east, a second 500mb
shortwave trough will spawn a second low over the northern Mid-
Atlantic Thursday evening. Periods of snow may envelope northern
Maine Thursday night as a cold front races south and forces
boundary layer temperatures to crash below freezing. There remains
some model spread in solutions regarding this second round of snow
Thursday night, so confidence in the snowfall placement and amounts
for the second round of snow is lower. At the moment, 48-hour WPC
probabilities show low chances (10-30%) for snowfall totals >4"
along the ME/Quebec border.


The chances for significant ice across the CONUS is less than
10 percent.


Mullinax





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FOUS11 KWBC 241849
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
249 PM EDT Tue Mar 24 2026

Valid 00Z Wed Mar 25 2026 - 00Z Sat Mar 28 2026


...Washington Cascades to Northern Rockies...
Days 1-2...

A shortwave trough rounding a deep, cold core low over the Gulf of
Alaska is directing an atmospheric river into the PacNW today with
high snow levels of 7000 to 8000ft. That trough axis approaches the
coast tonight before crossing the Cascades Wednesday and the
northern Rockies Wednesday night. Associated height falls drop the
snow level to 3500ft on the WA Cascades this evening before further
decreasing to around 2500ft Wednesday morning under the trough axis
(which is also when precip rates decrease). Snow probs for >6" are
40 to 80% above about 4000ft on the WA Cascades with some snow
getting down to 3500ft/Snoqualmie Pass level. Precip rates drop
off for the Cascades by Wednesday evening.

Farther inland, expect snow levels to decrease late tonight over
northwest MT and linger around 4000ft over northwest MT through
Wednesday. Day 1.5 snow probs for >6" are around 30% for the
highest Bitterroots and around 50% for the higher portions of the
Lewis Range in Glacier NP and the Mission Ridge which often stands
out for it's precip/snow forecast totals.


...Upper Midwest to Northern Maine...
Days 2-3...

Lee-side low development tonight in central Montana is expected
downstream of a trough axis approaching the Pacific Northwest. This
low tracks over Lake Superior Wednesday with snow generally in
Canada. However, it crosses Maine early Thursday producing moderate
snow over northern portions of the state. Day 2 snow probs for >4"
are limited to far northern NH terrain and only the higher points
of Maine.

A second and stronger wave crosses the northern Rockies Wednesday
night with an fgen band developing ahead over the northern Plains
early Thursday and shifts over the Northeast Thursday night. Some
snow mixed precip are likely with this band, though probabilities
are limited as of this time. The Day 2 ice probs for >0.01" are
40-70% from northern MN through the U.P. of MI.



Jackson


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FOUS11 KWBC 250707
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
307 AM EDT Wed Mar 25 2026

Valid 12Z Wed Mar 25 2026 - 12Z Sat Mar 28 2026

...Washington Cascades to Northern Rockies...
Days 1-2...

An approaching shortwave trough and an associated cold front will
track through the Pacific Northwest with upsloping winds and
sufficient Pacific moisture to produce mountain snow over the
Olympics and Cascades. Height falls and CAA in wake of a cold
frontal passage will cause snow levels to drop to as low as 2,500ft
this morning. Precipitation rates will gradually decrease
throughout the day, but persistent upslope flow will keep snow in
the forecast in the Cascades and Olympics as low as 2,500ft in
elevation through early Thursday morning. WPC probabilities depict
moderate chances (40-60%) for snowfall totals >4" at Snoqualmie
Pass and >8" at Stevens Pass. Most of the heaviest snowfall totals

8") will be confined to more remote elevations above 4,000ft.

Conditions at pass level should improve throughout the day Thursday
with snow concluding and higher late-March sun angles helping to
melt snow on paved surfaces.

Snow snow will spill east into the Northern Rockies as well, but
any accumulations will generally reside in the more remote
elevations (Glacier NPS the lone exception). Most snowfall amounts
will generally range between a coating to 3", but some locations
along the Lewis Range and Glacier NPS could see some localized
snowfall totals surpass 6" before snow concludes by Thursday
afternoon.


...Upper Midwest to Northern Maine...
Days 2-3...

A series of sheared 500mb vort maxima will generate light wintry
precipitation in portions of the Upper Midwest and northern Maine
the second half of the week. Focusing on northern Maine first, a
clipper system racing through southeast Canada Wednesday night will
escort a plume of moisture aloft within a corridor of 850-700mb
WAA over New England. Most of New England's boundary layer
temperatures will be too mild to support snow, with the lone
exception being far northern Maine. Snow will develop over northern
Maine late Wednesday night and linger through Thursday morning,
before finally ending Thursday afternoon. Snow fall rates will not
be overly heavy and the bulk of the snowfall will occur during the
day, which will limit snowfall totals thanks to the increasing
strength of the late March sun angle. Still, the border of Quebec
and northern Maine could still pick up some localized snowfall
totals >4" (WPC 24-hour probabilities show low-to-moderate chances
(20-40%). Some light snow may linger into Friday over the northern
Appalachians and northern Maine Friday morning as the next clipper
system passes well to the south.

At the same time as snow is unfolding across northern Maine on
Thursday morning, the next 500mb vort max is racing through the
Upper Midwest with a weak surface low tracking from eastern NE
into the heart of the MS Valley. Minor freezing rain and snow
accumulations will occur on the northern flank of the storm track
with WPC probabilities showing moderate-to-high chances (50-80%)
for >0.01" of ice accumulation from as far west as eastern ND to as
far east of the tip of Michigan's Mitt. It is worth noting WPC
probabilities for >0.1" of ice are <10%, so most ice accumulations
will be minor and struggle to accumulate on paved surfaces,
especially during the day on Thursday. The Huron Mountains are the
lone area where localized snowfall totals could top 2", but
otherwise the marginal boundary layer temperatures will make
snowfall more conversational rather than impactful on Thursday
morning.


The chances for significant icing across the CONUS is less than
10%.


Mullinax




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FOUS11 KWBC 251802
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
202 PM EDT Wed Mar 25 2026

Valid 00Z Thu Mar 26 2026 - 00Z Sun Mar 29 2026

...Washington Cascades to Northern Rockies...
Day 1...

Shortwave trough and associated cold front crosses the Cascades by
this evening with snow rates declining as snow levels fall from
3000ft to 1000ft. Day 1 snow probs for >4" are generally 30-60%
above about 3500ft.

Additional snow shifts east tonight through Thursday over the
Lewis Range in Glacier NP, the Bitterroots, Red Lodge portion of
the northern Absarokas in MT and the Bighorns. Day 1 snow probs are
30-50% across these areas of terrain.


...Northern Maine...
Day 1...

Weak low pressure over northern MI this afternoon strengthens as it
shifts across Maine on Thursday. WAA ahead of the low brings snow
to Maine late tonight/Thursday morning. Day 1 snow probs for >4"
are limited to far northern NH and the highest elevations and
northern border of Maine and generally 20-40%.


...Northern Plains and Upper Midwest...
Days 1 and 3...

A tight baroclinic zone develops tonight in zonal flow as low
pressure over the central Plains is met by strong high pressure
shifting from the Canadian Prairies. A wintry mix with generally
light rates develops along this boundary. Day 1 ice probs for

0.01" ice are 30-60% over eastern ND and across northern WI to

Upper MI, mainly falling late tonight through Thursday morning.
Little snow accum is expected.

High pressure shifting from the northern Plains to the Midwest
Friday through Saturday promotes some LES to develop off Lake
Superior on NW flow. Day 3 snow probs for >4" are 30-50% over the
eastern U.P.


The chances for significant icing across the CONUS is less than
10%.


Jackson



$$

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FOUS11 KWBC 260716
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
316 AM EDT Thu Mar 26 2026

Valid 12Z Thu Mar 26 2026 - 12Z Sun Mar 29 2026

...Northern New England...
Day 1...

A weak area of low pressure and a trailing front will bring some
light snow to northern New England. Amounts will be light and
generally limited to the higher elevations due to marginal
temperatures. WPC probabilities for at least 4 inches of snow are
low, generally 10-20%, above 2000-3000ft or so.


...Upper Midwest and western Great Lakes...
Days 1-3...

A frontal boundary across the region has prompted some light icing
overnight that will continue this morning after 12Z, particularly
over northeastern WI, southern U.P. of Michigan, and into northern
Lower Michigan. WPC probabilities for at least 0.01" icing are
moderate (40-70%) in these regions, but are below 5% for amounts
higher than a tenth of an inch.

Colder air behind this system will move across the Great Lakes
Friday afternoon into Saturday, coincident with a mid-level
shortwave. With 850mb temperatures dipping to below -15C, some lake enhanced/effect snow is forecast for parts of the U.P. into
northern Wisconsin. Another weak shortwave Saturday evening will
bring another light dusting to an inch of snow to the U.P. of
Michigan. Amounts even across all three days should be light (1-2"
or so), and WPC probabilities for at least 4 inches are only 10-20%
for the period.



The probability of significant icing across the CONUS for days 1-3
is less than 10%.


Fracasso

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FOUS11 KWBC 261933
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
333 PM EDT Thu Mar 26 2026

Valid 00Z Fri Mar 27 2026 - 00Z Mon Mar 30 2026

...Northern New England...
Day 1...

Low pressure lifting from northern New England into southeastern
Canada, along with a trailing front, will bring some light snow to
northern New England. Amounts will be light and generally limited
to the higher elevations due to marginal temperatures. WPC
probabilities for at least 4 inches of snow are low - capped at
10-20 percent and confined mostly to the far northern Green and
White mountains.

...Upper Midwest Great Lakes...
Days 2-3...

Cold air will continue to spread across the region as a mid-level
shortwave drops into the region by late Friday. With 850mb
temperatures dipping to below -15C, some lake enhanced/effect snow
is forecast for parts of region, with mostly light amounts
expected from northern Michigan to Upstate NY. Another weak
shortwave Saturday evening will bring another light dusting to an
inch of snow to the U.P. of Michigan. WPC probabilities indicate
that three-day snow accumulations will likely only be an inch or
two at most across the region.


The probability of significant icing across the CONUS for days 1-3
is less than 10%.


Pereira


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FOUS11 KWBC 270707
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
307 AM EDT Fri Mar 27 2026

Valid 12Z Fri Mar 27 2026 - 12Z Mon Mar 30 2026

...Western Great Lakes...
Day 1...

Cold air (850mb temperatures around -15C) over the western Great
Lakes will support light snow across the region tonight as a mid-
level shortwave moves through the region this afternoon/tonight.
Amounts will be light (1-2") but could touch 4" over parts of the
U.P. of Michigan where WPC probabilities are near 10%.


...Pacific Northwest/Northern Rockies...
Day 3...

Upper trough diving southeastward along the BC coast will move
into the Pacific Northwest on Sunday, bringing some mountain snow
to the Cascades and then into the northern Rockies along the
Divide. Colder air will rush in behind the cold front, allowing
snow levels initially near 2500-4000ft to fall to 1500-3000ft
overnight Sunday into early Monday (Cascades) but remain around
5000-600ft over northwestern MT. This will get some light snow to
the passes in WA, but probabilities for at least 4 inches of snow
are greater than 50% above about 4000-5000ft (Cascades) and 6000ft
over the Lewis Range.


The probability of significant icing across the CONUS for days 1-3
is less than 10%.

Fracasso

$$

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FOUS11 KWBC 271900
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Fri Mar 27 2026

Valid 00Z Sat Mar 28 2026 - 00Z Tue Mar 31 2026

...Pacific Northwest/Northern Rockies...
Day 3...

Guidance maintains general run-to-run continuity for the next
disturbance to impact the Northwestern U.S. by the end of the
weekend. Upper trough diving southeastward along the BC coast will
move into the Pacific Northwest on Sunday, bringing some mountain
snow to the northern Cascades and then into the northern Rockies
along the Divide. Colder air will rush in behind the cold front,
allowing snow levels initially near 2500-4000ft to fall to
1500-3000ft overnight Sunday into early Monday (Cascades) but
remain around 5000-600ft over northwestern MT. This will get some
light snow to the passes in WA, but probabilities for at least 4
inches of snow are greater than 50% above about 4000-5000ft
(Cascades) and 6000ft over the Lewis Range.


The probability of significant icing across the CONUS for days 1-3
is less than 10%.

Fracasso/Kleebauer




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FOUS11 KWBC 280647
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
247 AM EDT Sat Mar 28 2026

Valid 12Z Sat Mar 28 2026 - 12Z Tue Mar 31 2026

...Pacific Northwest/Northern Rockies...
Days 2-3...

A closed low south of the Gulf of Alaska will continue
southeastward today and slowly weaken into a positively-tilted
upper trough as its cold front moves through WA/OR on Sunday.
Despite some injection of mid-latitude Pacific moisture, the system
will be progressive and QPF will be limited. Snow levels will be
on the lower side -- 2500-4000ft in the Cascades before lowering
further behind the front to 1500-3000ft. This will bring some snow
to the passes and probabilities for at least 6 inches are at least
50% above about 3000ft or so for the northern Cascades.

Farther east, moisture will stream into the northern Rockies and
eventually into northern/northwestern Wyoming Sunday evening
through Monday and overnight into very early Tuesday, ending from west/northwest to east/southeast. Amounts will again be generally
light, with probabilities of at least 6 inches at least 50% above
about 5000ft in ID/MT but above 9000-10,000ft in WY.

Front end of the precip shield advancing across the Northern
Plains could support some light icing over northern ND early Monday
with generally a few hundredths of an inch possible.


The probability of significant icing across the CONUS for days 1-3
is less than 10%.

Fracasso


$$

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FOUS11 KWBC 281903
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
303 PM EDT Sat Mar 28 2026

Valid 00Z Sun Mar 29 2026 - 00Z Wed Apr 01 2026

...Pacific Northwest/Northern Rockies...
Days 2-3...

A closed low south of the Gulf of Alaska continues to trek to the
southeast as evidenced by the latest WV satellite analysis.
Expectation is for the low to slowly weaken into a positively-
tilted upper trough as its cold front moves through WA/OR on
Sunday. Despite some injection of mid- latitude Pacific moisture,
the system will be progressive and QPF will be limited. Snow levels
will be on the lower side -- 2500-4000ft in the Cascades before
lowering further behind the front to 1500-3000ft. This will bring
some snow to the passes and probabilities for at least 6 inches are
at least 50% above about 3000ft or so for the northern Cascades.

Farther east, moisture will stream into the northern Rockies and
eventually into northern/northwestern Wyoming Sunday evening
through Monday and overnight into very early Tuesday, ending from west/northwest to east/southeast. Amounts will again be generally
light, with probabilities of at least 6 inches at least 50% above
about 5000ft in ID/MT but above 9000-10,000ft in WY. Highest totals

8" are most likely across the Lewis Range in northwest MT and the

Absoroka's in southern MT into northwest WY with the Lewis Range's
likely to see a foot or more above 7000ft.

Front end of the precip shield advancing across the Northern
Plains could support some light icing over northern ND early Monday
with generally a few hundredths of an inch possible.

The probability of significant icing across the CONUS for days 1-3
is less than 10%.

Fracasso/Kleebauer





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FOUS11 KWBC 290701
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
301 AM EDT Sun Mar 29 2026

Valid 12Z Sun Mar 29 2026 - 12Z Wed Apr 01 2026

...Pacific Northwest/Northern Rockies...
Days 1-2...

A sharp positively-tilted upper trough just west of Vancouver this
morning will continue to push eastward as its cold front moves
through WA/OR today. Despite some infusion of mid-latitude Pacific
moisture, the system will weaken a bit and remain progressive,
limiting QPF amounts. Lower snow levels around 2500-4000ft in the
Cascades this morning will lower behind the cold front to
1500-3000ft. This will bring some snow to the passes and
probabilities for at least 6 inches are at least 50% above about
3000-3500ft or so for the Washington Cascades.

Farther east, moisture will stream into the northern Rockies late
this afternoon/tonight and eventually into Wyoming late Monday into
Tuesday, ending from west/northwest to east/southeast as the cold
front moves to the east quicker than it sinks to the south. Amounts
will again be generally light, but northwestern Montana may see
totals in excess of a foot around Glacier NP (50-80% chance). In
general, probabilities of at least 6 inches of snow are at least
50% above about 5000ft in ID/MT but above 9000-10,000ft in WY. The
Absarokas in southern MT into northwest WY may also see slightly
higher totals due to some local surface convergence.

Front end of the precip shield advancing across the Northern
Plains could support some light icing (generally a few hundredths
of an inch) over northern ND early Monday then into northeastern MN
and perhaps the U.P. of Michigan as the system redevelops over the
Plains/Corn Belt.


...Northern New England...
Day 3...

The system over the Great Lakes on Monday (above) will move into
the Northeast on Tuesday. Marginally cold temperatures will be
limited to northern NY/VT/NH and much of interior Maine as
precipitation advances into the region Tuesday morning along and
ahead of a surface warm front. With the main area of low pressure
quite far to the west early Tuesday (WI or into Lower MI), cold air
may hang on longer in sheltered areas over northern New England
which would support some light snow to start but then more likely a
period of freezing rain. AI guidance suggests colder temperatures
than the dynamical models Tuesday night into Wednesday morning,
hinting at at least non-trivial amounts of freezing rain (though
the better signal lies across Canada near/northeast of Ottawa). For
now, kept amounts to around a tenth of an inch but with the
potential to trend higher in the next couple of days. WPC
probabilities for at least 0.10" icing are >30% over northwestern
Maine.


...Sierra Nevada to the CO Rockies...
Day 3...

Combination of the tail-end of the Pacific Northwest/northern
Rockies system today/Monday and an incoming weak shortwave out of
the Pacific Tuesday afternoon will bring some light to perhaps
modest snow to the Sierra and CO Rockies and dotted across the
Great Basin in between. Snow levels will be high -- 8000-9000ft --
with WPC probabilities for at least 6 inches of snow between about
40-80% above 9000-10,000ft.


The probability of significant icing across the CONUS for days 1-3
is less than 10%.

Fracasso



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FOUS11 KWBC 291906
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
306 PM EDT Sun Mar 29 2026

Valid 00Z Mon Mar 30 2026 - 00Z Thu Apr 02 2026

...Pacific Northwest/Northern Rockies...
Days 1-2...

Trough axis from this morning over British Columbia will continue
to propagate to the east over the next 12+ hours. A cold front
analyzed just off the coast of WA is making headway into the
northwestern fringes of the state which will lead to a decay of
precipitation from west to east, post front. Snowfall will continue
across the highest elevations of the Olympics, as well as over the
northern Cascades through this evening before precipitation wanes
overnight into the early morning hours tomorrow. Additional light
to moderate snowfall accumulations are anticipated through the
aforementioned time frame before conditions settle and snowfall
potential ceases.

Farther east, moisture will continue to stream into the northern
Rockies through tonight and eventually into Wyoming late Monday
into Tuesday, ending from west/northwest to east/southeast as the
cold front moves to the east quicker than it sinks to the south.
Snowfall totals across the Lewis Range will likely exceed a foot
for the entirety of the event before the precipitation shield
shifts south in wake of the front. Additional accumulations >6" are
running between 50-80% above 7000ft from now until late Monday
afternoon. Snowfall levels will settle closer to 8000-10,000ft in
WY leading to lighter accumulations overall with the setup. The
Absarokas in southern MT into northwest WY are the exception where
slightly higher totals are forecast due to some local surface
convergence and terrain enhancement along and ahead of the cold
front.

Front end of the precip shield advancing across the Northern
Plains could support some light icing (generally a few hundredths
of an inch) over northern ND early Monday then into northeastern MN
and perhaps the U.P. of Michigan as the system redevelops over the
Plains/Corn Belt.

...Northern New England...
Day 3...

The system over the Great Lakes on Monday (above) will move into
the Northeast on Tuesday. Marginally cold temperatures will be
limited to northern NY/VT/NH and much of interior Maine as
precipitation advances into the region Tuesday morning along and
ahead of a surface warm front. With the main area of low pressure
quite far to the west early Tuesday (WI or into Lower MI), cold air
may hang on longer in sheltered areas over northern New England
which would support some light snow to start but then more likely a
period of freezing rain will materialize as southwesterly flow
aloft advects in some warmer air within the upper portion of the
boundary layer into the mid-levels. Latest WPC probabilities for

0.1" of ice accumulation are upwards of 20-40% for the D3 period,

majority of which will fall in the evening to overnight hours
Tuesday into Wednesday morning. A low-end chance for up to a 0.25"
is hovering between 5-15% within an axis aligned west to east
across northwest ME through much of Aroostook county and the
northern sections of neighboring Piscataquis/Penobscot counties.
Will monitor trends closely, but mainly expecting modest totals
with generally a 0.05-0.15" range for the forecast.


...Sierra Nevada to the CO Rockies...
Day 3...

Combination of the tail-end of the Pacific Northwest/northern
Rockies system today/Monday and an incoming weak shortwave out of
the Pacific Tuesday afternoon will bring some light to perhaps
modest snow to the Sierra and CO Rockies and dotted across the
Great Basin in between. Snow levels will be high -- 8000-9000ft --
with WPC probabilities for at least 6 inches of snow between about
40-80% above 9000-10,000ft. Heavier snowfall into the Central
Rockies will occur just after the D3 window (D3.5) where
probabilities are closer to 50-80% for at least 6" when advancing
just beyond the D3 window.

Fracasso/Kleebauer






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FOUS11 KWBC 300742
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
342 AM EDT Mon Mar 30 2026

Valid 12Z Mon Mar 30 2026 - 12Z Thu Apr 02 2026

...Northern Rockies...
Day 1...

Cold front moving eastward through the Northern Rockies will
continue to bring generally light snow to the central ID ranges
into the Absarokas and Bighorns today. The snow associated with
this system will be supplanted by incoming moisture from a Pacific
system. Through 12Z Tue, WPC probabilities of an additional 6
inches of snow are >50% over the Absarokas.


...Sierra Nevada to the CO Rockies...
Days 2-3...

An incoming shortwave out of the Pacific Tuesday afternoon will
bring some light to perhaps modest snow to the Sierra, Wasatch,
Uintas, and CO Rockies as it zips eastward. Snow levels will be
high (8000-9000ft though falling ~1000ft as the trough moves
through) with WPC probabilities for at least 8 inches of snow are
at least 50% above 7500ft (Sierra) to 10,000ft (CO). Totals in the
CO Rockies may eclipses a foot above 11,000ft.


...Pacific Northwest...
Day 3...

Next system out of the Gulf of Alaska will barrel toward the
Pacific Northwest on Wednesday, bringing a more substantial influx
of moisture ahead of its rather robust cold front. Trailing mid-
level low will sustain modest snowfall totals into the Cascades and
points eastward to the northern Rockies yet again. The focus may
be the southern WA Cascades, OR Cascades, central ID ranges, and
NorCal ranges including the northern Sierra as the cold front
reaches there by the end of this forecast period. Snow levels will
range from 4000-7000ft (north to south) ahead of the front, then
fall to 2500-6000ft post-FROPA. WPC probabilities for at least 8
inches of snow are >50% above 5000ft or so in the OR Cascades and
7000ft in NorCal and across the northern Great Basin.


...Northern New England...
Day 2...

The system exiting the High Plains today will move into the
Northeast on Tuesday. Marginally cold temperatures will be limited
to northern NY/VT/NH and much of interior Maine as precipitation
advances into the region Tuesday morning along and ahead of a
surface warm front. With the main area of low pressure quite far to
the west early Tuesday (WI or into Lower MI), cold air may hang on
longer in sheltered areas over northern New England which would
support some light snow to start but then more likely a period of
freezing rain will materialize as southwesterly flow aloft advects
in some warmer air within the upper portion of the boundary layer
into the mid-levels. With the surface low track potentially no
farther north than the VT-NH/Quebec border, this could prolong the
freezing rain threat for much of the event. WPC probabilities for

0.25" of ice accumulation are 10-30% across northwest ME.

...Upper Midwest/Corn Belt/Western Great Lakes...
Day 3...

System exiting the Rockies Wednesday will lift to the northeast
toward the Great Lakes. With a generous fetch of moisture from the
Gulf northward and a marginally but sufficiently cold thermal
profile north of about I-80, an expanding area of
snow/sleet/freezing rain is increasingly likely for much of the
region overnight Wednesday through Thursday (continuing beyond this
forecast period). Uncertainty is high, compounded by the spread in
ptypes from the models/ensembles. For now, through 12Z Thursday,
expect a west-to-east swath of snow farthest to the north (SD
eastward to WI and MI) and sleet/freezing rain just to the south
(Iowa eastward through southern WI into Lower MI). Again, these
areas may shift over the next couple of days depending on how the
storm evolves over/east of the Rockies. Just through 12Z Thursday,
WPC probabilities for at least 4 inches of snow are 10-40% from SD
eastward to about northern WI. For freezing rain, probabilities for
at least 0.10" icing through 12Z Thursday are 10-50% over southern
WI and into central Lower MI. The probabilistic WSSI is already
showing 20-40% chance of moderate impacts day 3, and even higher
beyond. See our extended forecast discussion (PMDEPD) for more
information.



Fracasso

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FOUS11 KWBC 301900
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Mon Mar 30 2026

Valid 00Z Tue Mar 31 2026 - 00Z Fri Apr 03 2026

...Northern Rockies...
Days 1-3...

A cold front pushing south and east through the northern Rockies
today will work together with an influx of 700-300mb layer moisture
and the diffluent right-entrance region of a 250mb jet streak to
produce snow from the Bitterroots on east through the Absaroka,
Wind River, Teton, and Big Horn Ranges tonight and into Tuesday.
Snow ill linger through Tuesday due to weak upslope easterly flow
from high pressure over southern Saskatchewan and and moist SWrly
700mb winds maintaining a steady fetch of Pacific moisture.
Snowfall rates will generally be on the light side on Tuesday with
weakening synoptic-scale lift aloft. Through 00Z Wednesday, WPC
probabilities depict moderate-to-high chances (50-80%) for snowfall
totals >4" in the Absaroka, Tetons, Wind River, and Big Horn
ranges. The peaks of the MT/WY Absaroka and the Wind River
mountains may witness some localized snowfall totals approaching a
foot.

Periods of light mountain snow will continue through Tuesday night
and Wednesday morning before the next round of heavier mount snow
arrives Wednesday night. The 500mb low responsible for the heavy
mountain snow in the Pacific NW will direct its rich plume of
Pacific moisture into the Northern Rockies. At the same time, its
diffluent 250mb left-exit quadrant will be in place over the
region at the same time healthy 500mb PVA occurs. There is no
frigid air-mass in advance of this system, keeping most heavy
snowfall above 4,000ft from the Bitterroots and Sawtooth on east to
the Lewis Range. For the Absaroka, Tetons, and as far east as the
Big Horns, heavier snowfall totals will be at/above 7,000ft. WPC
probabilities highlight at least moderate chances (>50%) for
snowfall totals >6" in the peaks of all these aforementioned ranges
with localized totals up to a foot possible. The WSSI-P shows that
there are high chances (>70%) for Minor Impacts in the peaks and
passes of these regions, but Moderate Impact probabilities remain
on the low side (<20%). This indicates some hazardous travel is
possible, although more significant impacts are not anticipated at
this time.

Many of these mountains regions are either right around normal, or
below normal for the season-to-date snowfall, so snowfall in the
northern Rockies will be more beneficial than harmful as we
approach the start of the warm season.


...Pacific Northwest...
Days 2-3...

A powerful closed upper-low diving southward from the Gulf of
Alaska will be the catalyst for renewed mountain snow in the
Olympics, Cascades, the Salmon/Siskiyou of northern CA, and as far
east as the Blue Mountains Wednesday afternoon and continuing
through Thursday. The approaching 850-500mb layer heights
associated with the closed low are below the 10th percentile and
snow levels will be able to drop as low as 2,000ft Wednesday night
in the Olympics, Cascades, and even as far south as the Siskiyou.
A steady stream of Pacific moisture embedded within SWrly mean
layer flow, suitable for upslope enhancement as well, will also
favor locally heavy snowfall rates in these ranges. Drier air
should move in on the backside of the closer low by Thursday
afternoon, although lingering westerly low-level winds should
support light-to-moderate snow in the Cascades for the remainder of
the day on Thursday.

WPC 48-hour probabilities show high chances (>70%) for snowfall
totals >12" in the OR Cascades above 4,000ft with at least
moderate chances (>50%) for snowfall totals >8" at elevations

3,000ft. The WA Cascades will see lesser snowfall totals than

their OR neighbors given the best Pacific moisture plume will
reside farther south, but several inches of snow at pass level
(Snoqualmie and Stevens) are expected. The peaks of the Siskiyou
and Salmon Mountains of northern CA, as well as the peaks of the
Blue Mountains of northeast OR, all have high chances (>70%) for
snowfall totals surpassing 8". Most impacts on the WSSI currently
show Minor Impacts with locally Moderate Impacts depicted in the
peaks of these mountain ranges through Thursday.


...Sierra Nevada to the Colorado Rockies...
Days 2-3...

An incoming shortwave out of the Pacific Tuesday afternoon will
bring some light to perhaps modest snow to the Sierra Nevada,
Wasatch, Uintas, and CO Rockies as it zips eastward. Snow levels
will be high (8000-9000ft though falling ~1000ft as the trough
moves through) with WPC probabilities for at least 8 inches of snow
are at least 50% above 7500ft (Sierra) to 10,000ft (CO). Totals in
the CO Rockies may eclipses a foot above 11,000ft.


...Northern New York and New England...
Days 1-3...

A lingering front will become the focus for organized
precipitation as a series of low-amplitude southern stream waves
interact with deepening moisture. Light precipitation will spread
across the region on Tuesday with the first wave, followed by
heavier precipitation Tuesday night as a following wave
strengthens ahead of a more amplified northern stream wave moving
across Quebec. While southwesterly flow aloft advects warmer air
into the mid-levels, a shallow but stubborn layer of subfreezing
air is expected to remain entrenched across northern New England.
Forecast soundings support mostly snow across far northern Maine,
while areas further south, including areas as far south as Down
East Maine may see snow transitioning to accumulating ice. The
latest guidance indicates that northwestern Maine is the area
mostly likely to be impacted with heavier ice accumulations, with
WPC probabilities showing 30-50 probabilities for ice accumulations
of 0.10 inch or more centered across the region 00Z Wednesday -
00Z Thursday. Northern Aroostook County is likely to be the focus
for the heaviest snow accumulations, with WPC probabilities
indicating that amounts greater than 4 inches are likely (50-70
percent).

Following a brief dry period Wednesday night, the threat for
wintry weather is forecast to return to the region on Thursday as
the system detailed below lifts toward the Great Lakes -- bringing
moisture back into the region as cold high pressure remains
anchored to the north. For the 24-hr period ending 00Z Friday, WPC probabilities indicate that additional accumulating ice is likely
for parts of the Adirondacks, with lower probabilities extending
east to Down East Maine.

...Upper Midwest/Corn Belt/Western Great Lakes...
Day 3...

An amplified shortwave exiting the Rockies Wednesday night will
lift toward the Great Lakes, directing a deep plume of Gulf
moisture to the north. As precipitation blossoms across the region
on Thursday, a sharp thermal gradient north of the I-80 corridor
will support a broad swath of wintry weather, topped by west-east
band of heavy snow and bordered to the south by a corridor of
sleet and freezing rain, with significant ice accumulations
possible.

Through 00Z Friday, WPC probabilities greater than 50 percent for
snow accumulations greater than 4 inches are largely confined to
the Minnesota Arrowhead eastward to the western U.P.

At this point, guidance indicates that significant icing will be a
more far-reachiing concern. By 00Z Friday, the P-WSSI shows
probabilities greater than 50 percent for moderate impacts due to
icing continuing to expand across the region, now covering parts
of southeastern Minnesota and northeastern Iowa, as well as large
potions of central and southern Wisconsin, and northern and central
Lower Michigan. For the 24-hr period ending 00Z Friday, WPC
probabilities for ice accumulations greater than 0.10 inch are
50-70+ percent across this area, with the higher probabilities
generally corresponding with 30-50 probabilities for ice
accumulations greater than 0.25 inch.

Mullinax/Pereira/Fracasso


$$

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