FOUS30 KWBC 151812 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
212 PM EDT Mon Jul 15 2024

Day 1
Valid 185Z Mon Jul 15 2024 - 12Z Tue Jul 16 2024

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR ACROSS
PORTIONS OF NORTHERN ILLINOIS, INCLUDING THE CHICAGO METRO...

..1810Z Update...

In coordination with the local Chicago WFO, a targeted upgrade to a
Moderate Risk was made to encompass much of Northern IL, including
the Rockford and Chicago metro areas. Previous 48 hrs have been
impactful across the aforementioned area with locally 5-10" of
rainfall from a succession of three MCS as they moved through the
area. Despite the overall progressive nature of the expected
complex later today, the antecedent conditions coupled with rates
of 1-3"/hr over very saturated soils and flood prone urban
corridors were enough to warrant a targeted upgrade to the MDT risk
across that area.

Kleebauer

...16Z Update Summary...

The SLGT risk across the Midwest was expanded in all directions
with a greater emphasis to the north, south, and east where the
forecast track of the next convective complex will likely cause
some enhanced flash flood issues during its progression. A MRGL
risk was added across portions of Southern New England for isolated
flash flood within a zone of enhanced convergence. The MRGL risk
across the Northeast was expanded a bit further east as well to
reflect some of the trends within the QPF field on recent CAMs as
they have a better handle on the approaching shortwave and remnant
MCV currently pushing through Southeast Ontario. The MRGL risk
across the Southwest was linked and expanded somewhat to encompass
the higher instability reflection across the region where isolated
flash flood concerns will be plausible.

...Midwest through the Ohio Valley...

Area convection within the Upper Mississippi Valley is in the
process of weakening with some of the remnant energy expected to
pivot southeast within the mean flow aloft. A cold front at the
surface is analyzed over Southwest MN with a surface low expected
to motion to the northeast into the Northern Great Lakes by the
evening. The cold front will slide to the southeast allowing for
increasing convergence within the confines of a building
moist/unstable axis present between Eastern IA and points east
encompassing most of Southern WI through Northern IL. These areas
have been impacted significantly leading into the upcoming
convective pattern with some remnant flooding still located within
portions of Rockford and Chicago after the succession of 3 MCS's
the past 48 hrs. The priming of the soils in conjunction with the
incoming wave of convection is concerning as the threat will lean
on the higher-end of potential impacts given the current situation.

Convection will fire late this afternoon and quickly grow upscale
as it moves from Eastern IA into Southern WI and Northern IL, a
similar path to the previous complex that impacted the area last
night. Those areas that were hit previously will maintain the SLGT
risk from prior forecast with a higher end wording on locally
significant impacts possible across the corridor from Rockford over
into Chicago and the surrounding suburbs. The cold front will
propagate south with the assistance from cold pool generation from
the expected complex. After 00z, increasing LLJ presence will play
a significant role in enhancing the rainfall potential within the
confines of the boundary as the flow shifts parallel to the front
allowing for convective training and backbuilding to occur on the
upwind flank of the complex. This has been a consistent signature
within the latest CAMs with the HREF blended mean QPF footprint
depicting the potential pretty well across the IA/IL border south
of Davenport to points east into western IN. This is a relevant
signature given the synoptic and mesoscale evolution anticipated
with an enhanced probability field accompanying within that zone of
interest.

The two primary areas will lie within that northern and southwest
flank of the complex. Neighborhood probabilities for at least 2"
are very high within both corridors with a solid 40-70% outline
within both areas. The 1" EAS signatures were also more robust in
those zones with some lighter 2" signatures in the same region.
Considering those variables, there was enough confidence to
maintain the SLGT risk and including some higher-end SLGT wording
within those two corridors above. The SLGT was also expanded to the
east over portions of Southern MI through Northern and Central IN
as the complex will continue propagating eastward overnight with
locally heavy rainfall in-of those areas downstream. There is a
potential for a targeted upgrade within portions of Northern IL if
the setup repeats or has a higher impact across the areas where
they have been hit recently leading to greater sensitivities to
flood concerns.

...Southern New England...

A small, but fairly substantial mid-level perturbation will advect
eastward into Southern New England from the west, entering an area
of modest low-level convergence and sufficient surface buoyancy
located within parts of Northern CT up through Central MA later
this afternoon. A fairly substantial boundary layer moisture
presence is reflected within the current observed PWATs and surface
dew points located across all of the area. Diurnal destabilization
and the approach of the mid-level reflection will allow for the
development of a line of convection across the above areas, riding east-northeast within the confines of a sharp theta-E gradient
aligned over basically the I-90 corridor. Considering the
environment and some of the probability signals being a bit robust
over the highlighted area. In coordination with the local BOX WFO,
a small MRGL risk was added over portions of Southern New England,
not including greater Boston or Southeast MA.

Kleebauer

...Southwest...
Monsoon moisture will fuel another day of afternoon showers and
thunderstorms, with isolated flash flooding remaining a concern
from southeastern Arizona and southwestern New Mexico into the
Mogollon Rim. Models have been underplaying the convection
development further to the west into southern California.
Considering a somewhat decent signal with the SBCAPE fields off the
recent CAMs and PWAT anomalies within the interior of SoCal and
Southern NV, have expanded the MRGL risk and connected the
separated risk areas to become a more uniform MRGL over the region.

Pereira/Kleebauer

Day 2
Valid 12Z Tue Jul 16 2024 - 12Z Wed Jul 17 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
MID MISSISSIPPI AND OHIO VALLEYS...

...Central Plains to the Northeast...
As a broad upper trough begins to amplify over the Great Lakes, the
associated surface boundary and accompanying moisture pool will
become a focus for showers and storms and the potential for heavy
rainfall amounts. Southwesterly inflow into the front will support
PWs climbing upwards of 2 inches from the mid Mississippi Valley
eastward into the Ohio Valley. This is also where the guidance
shows the best mid-to-upper level forcing, raising the potential
for west-to-east training storms and heavy accumulations. The
general model consensus shows the greater threat has shifted a
little further south and east, but is overall close to the previous
axis. Therefore, a Slight Risk was maintained from central
Missouri eastward to far western Pennsylvania. Some of the
deterministic guidance do show amounts that would raise Moderate
Risk concerns. However, given the model spread, opted not to
include any upgrades at this point.

While the model consensus indicates the greater threat for
widespread moderate to heavy amounts is further east, there is a
notable signal for locally heavy amounts developing over the
central High Plains, especially over eastern Colorado and
western Kansas. Mid-level energy spilling off the top of the ridge
and interacting with upslope flow and moisture pooling along the
western edge of the surface front will likely support storms
developing along the high terrain before moving eastward. While
differing in the details, most models show at least locally heavy
rainfall amounts, raising at least isolated flash flooding
concerns across the region.

...Southwest...
Greater coverage of isolated to scattered diurnal convection is
expected as the upper high currently in place weakens. This will
allow more showers and storms to develop further to the north,
extending the threat for isolated flash flooding across a greater
portion of northern Arizona and New Mexico.

Pereira

Day 3
Valid 12Z Wed Jul 17 2024 - 12Z Thu Jul 18 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
COLORADO AND NEW MEXICO...

...Southwest to the central and southern Rockies...
A Slight Risk was introduced from south-central Colorado to central
New Mexico, where moist upslope flow will support increasing
coverage of showers and storms and locally heavy amounts. This will
raise the potential for flash flooding, especially across
vulnerable areas. Guidance indicates a notable increase in low
level moisture transport, raising PW anomalies to 1.5 standard
deviations above normal across central New Mexico. This moisture
along with weak flow aloft and daytime heating, is expected to
support slow-moving storms capable of producing heavy rainfall
rates. Vulnerable areas, including burn scars, urbanized areas, and
areas of complex terrain will be most susceptible to flash
flooding.

Elsewhere, the potential for diurnal convection producing at least
isolated concerns for heavy rainfall and flash flooding will
continue to expand across the Southwest.

...Southern Plains to the Northeast...
Widespread coverage of moderate to locally heavy amounts,
extending from Oklahoma and northern Texas all the way to the Mid
Atlantic and southern New England, can be expected as a cold front
continues to drop slowly south through the central and eastern
U.S. this period. Model spread contributed to the decision to
maintain a broad Marginal Risk across this region for now. However,
there are some model signals that an upgrade to a Slight Risk may
be required across some areas at some point. This includes areas
from eastern Oklahoma through northern Arkansas, where some of the deterministic models show heavy amounts developing as mid-level
energy moving through the base of the trough interacts with a
deeper moisture pool (PWs ~2 inches) along the front. Other areas
include portions of the Ohio Valley and the Mid Atlantic, where
there are signals for at least locally heavy amounts as well.

Pereira

Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5WFml_hDqDN6BXOYhORAlvz1BuLc0etqy6yADXZWIFXQ= 5uPfesbvJuMsoVXinppQg6aWT8FMbm3-4V_SakPuVXBTCQo$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5WFml_hDqDN6BXOYhORAlvz1BuLc0etqy6yADXZWIFXQ= 5uPfesbvJuMsoVXinppQg6aWT8FMbm3-4V_SakPuuC7aXF8$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5WFml_hDqDN6BXOYhORAlvz1BuLc0etqy6yADXZWIFXQ= 5uPfesbvJuMsoVXinppQg6aWT8FMbm3-4V_SakPuHdS9vxU$=20

=3D =3D =3D
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FOUS30 KWBC 210838 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
438 AM EDT Sun Jul 21 2024

Day 1
Valid 12Z Sun Jul 21 2024 - 12Z Mon Jul 22 2024

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHWEST AND THE WESTERN CAROLINAS...

...Western Carolina's...

General pattern persistence across the Southern Mid Atlantic will
yield another round of scattered to widespread convection in-of
the Carolinas with some locations setup to see a greater emphasis
for heavy rainfall. A few weak mid-level perturbations will advect
northeast within the mean flow, encroaching on the Piedmont of the
Carolina's by later this morning. The coupling of increased upper
support with a strong diurnal destabilization pattern will promote
the threat of stronger cell cores with heavy rain potential due to
anomalous moisture lingering along and south of the quasi-
stationary front to the north. Recent trends within the HREF and
associated CAMs have been for an increase in heavy rainfall for
points along and west of I-85 where the mid-level ascent will be
maximized along with the favored instability. Convection will
likely fire along the terrain of the escarpment up through the
Appalachians of NC before drifting to the east and northeast away
from the terrain. Probabilities for locally enhanced rainfall
exceeding 2" is very high (>70%) for much of Western NC down into
the far Upstate portion SC to the north of GSP. There's some hints
of upwards of 5" within the probability fields and individual CAMs
members along the escarpment up through areas like Boone points
east towards Greensboro. This area has seen its fair share of heavy
rain in the past 24-48 hrs at times, so the latest FFGs are lower
than climo. In coordination with the surrounding WFOs that bridge
coverage in the Western Carolina's, have introduced a SLGT risk
across the area encompassing much of the area west of the I-85
corridor.

...Southwest and Southern Rockies...

A pattern of general persistence within the mid and upper-levels
will lead to an ongoing threat of convective development in-of the
Southern Rockies and adjacent terrain of NM due to primed
environmental destabilization coinciding with a progression of mid-
level vortices streaming down the eastern flank of the ridge
across the Western U.S. A slight weakening of the ridge will allow
for an expansion of the convective threat to migrate westward into
the Mogollon Rim with some deterministic output signaling some
formidable amounts within the terrain. The primary areas of
interest within the current SLGT will reside within the complex
terrain and areas surrounding the remnant burn scars located within
the Sacramento's and Sangre de Cristos. Secondary areas of focus
include the NM Bootheel, Southeast AZ terrain around the Huachucas,
as well as the Eastern NM High Plains into the Northwest Permian
Basin of Texas.

The latter of the aforementioned areas is a newer development
within the latest ensemble means with a focus along a remnant
outflow that bisect the Caprock down into the Permian Basin,
outlined by a marginal theta-E gradient in place from Clines
Corner, NM down close to I-20 around the Midland/Odessa corridor. A
shortwave currently analyzed over CO will continue to make headway
to the south around the eastern flank of the ridge eventually
aiding in convective initiation across east-central NM by the
afternoon. Multi-cell cluster of thunderstorms will congeal by
prevailing cold pools and migrate to the southeast, riding right
along the theta-E gradient that will maintain presence through the
afternoon. There's a growing consensus that storms will be able to
hold together and impact a large area encompassing the Caprock of
Eastern NM down through the Northwest Permian Basin before
potentially collapsing in the evening. There is a chance this holds
together to the I-20 corridor and provides some heavier rain
within the confines of the Midland/Odessa area, but the probability
is lower compared to the Northwestern areas up across Southeastern
NM up through the Caprock along the TX/NM state lines. HREF
probabilities are highest for at least 2" within the confines
above, including some >70% output being displayed within the
Northwest Permian up through Lea and Roosevelt Counties in NM.
Despite a very dry signal within the soil moisture availability
over the region, rainfall rates in excess of 1.5"/hr will be
plausible given the elevated moisture presence as noted within the
latest NAEFS PWAT anomalies approaching 1-1.5 deviations above
normal across much of Southeast NM extending southeastward into the quasi-stationary front aligned near I-10.


The previous SLGT risk was maintained, but did allow for an eastern
extension to account for the increasing organized convective threat
aimed for portions of Southeastern NM down into West Texas.

...Oklahoma...

A compact but well-defined surface wave will linger within the
base of the mean trough carved out across the Mid-Mississippi
Valley back down into the northern fringes of the Southern Plains
in OK. Current IR satellite indicates a blossoming of convection
over Northeastern OK this evening that will lead to some locally
heavy rainfall close to Tulsa and surrounding locales. Hi-res
deterministic is consistent on the surface reflection sticking
around through the first half of the period with a short term
degradation of the convective field after 12z, but comes back in
earnest due to the addition of the diurnal destabilization along a
surface trough extending near and south of the surface low. Signals
for increasing low-level convergence within the confines of low
are present within several CAMs outputs later this morning and
afternoon leading to a narrow corridor of heavy rain that could see
totals breach 4" within a short period of time. The main threat is
confined within the small circulation with the northern fringes of
the low being the prime focus for where modest training could
occur. There's a small footprint within the ensemble means of 2+"
just south of the Tulsa metro with accompanying neighborhood
probabilities of >5" up between 25-40% in the same area. Whether
that's the exact location or not, the areal extent of flash flood
concerns is small due to the compact nature of the setup. A MRGL
risk was maintained from previous forecast, but want to make
mention the threat could trend towards more locally significant
impacts where the training convective pattern establishes itself.
Look for future MPD's on the threat as we move towards the late
morning and early afternoon hours.

Kleebauer


Day 2
Valid 12Z Mon Jul 22 2024 - 12Z Tue Jul 23 2024

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS OF THE SOUTHERN ROCKIES, TEXAS THROUGH THE ARKLATEX...

...Southern Plains...

A quasi-stationary front will bisect much of the state of Texas
with a westward extension into the Southwest TX terrain back
through the Big Bend, Edwards Plateau, Hill Country, all the way
out to the ArklaTex. Mid-level energy from the northwest will
navigate southeast towards the higher terrain south of I-20,
migrating slowly eastward within the confines of the front. The
added upper forcing in conjunction with the increasing low-level
convergence along the stationary front will induce a swath of
stronger thunderstorms capable of significant rainfall within any
cell core. Latest NAEFS PWAT anomalies signals a solid +2
deviations from climo for the moisture field present across much of
the central portions of TX back into the Stockton Plateau. Cell
initiation across the higher terrain out west will lead to
convective clustering with outflow generation stemming from areal
thunderstorm coverage, eventually propagating to the east into the
I-35 corridor in Central TX by later Monday afternoon and evening.
Precip totals within the initial cell development are generally
between 1-2", but some higher totals exceeding 4" will be possible
across the Lower Trans Pecos through the Southern Edwards Plateau.
The heaviest core of precip will lie within the eastern extent of
the Edwards Plateau across into Hill Country until it reaches the
I-35 corridor near Austin/San Antonio. This is where ensemble mean
QPF has been the most consistent for totals exceeding 2" with
indications of up to 3" in areal average QPF within Hill Country
and individual deterministic output exceeding 6" in places hit with
repeated cells. Mean storm motions within the confines of the
boundary are weak meaning slow moving convective clusters with
rainfall rates between 2-3"/hr are possible along that frontal
boundary. The SLGT risk from previous forecast was maintained but
expanded to the west to include more of the Stockton Plateau given
the latest trends within the mean QPF and favorable environment
over the area leading into the evolving event.

Further to the northeast through Northeast TX into the ArklaTex,
energy from the southwest will eventually advect northeastward with
convective generation during the afternoon and evening hours
becoming more organized with the additional upper support. Some
cell clusters will be capable of locally heavy rainfall extending
along the stationary front with some convective training plausible
due to similar conditions from upstream. Totals are not as prolific
within the means across the above region, but some totals of 2-4"
are not out of the question, so felt there was no reason to make
significant adjustments to the previously inherited SLGT risk.

...Southwest and Southern Rockies...

Scattered thunderstorms will develop once again within the confines
of the Sangre de Cristos with highest impacts situated over the
complex terrain and any burn scars within the mountain chain.
Totals are not expected to be as prolific compared to recent days
with less of a favorable mid-level pattern and lower SBCAPE
forecast. Regardless, considering the expected convective
development and the very sensitive nature of the flash flooding
potential within the burn scars, there was enough merit to continue
the focused SLGT risk across the Mountains with an extension down
into the Sacramento's due to the ongoing issues caused by the burn
scarring near Ruidoso. This is a lower end SLGT risk threshold with
impact based reasoning for the risk continuity.

Across the rest of the Southwestern U.S, the upper pattern will
shift to have less ridge potency leading to an expansion of the
convective risks a bit further west to include the Lower Colorado
River valley between CA/AZ/NV. The best threat will still be across
the Mogollon Rim where scattered thunderstorm coverage will likely
spawn some totals exceeding 1" within a short period of time along
the terrain of central AZ. The coverage and moisture anomalies were
not primed enough to warrant an upgrade at this time, but the
threat is still a mid to higher end MRGL risk, on the cusp of a
potential upgrade if the setup becomes more pronounced within the
means.

...Southeast to Southern Mid Atlantic...

Persistent surface front bisecting much of the Southeastern U.S up
through the Southern Mid Atlantic will continue the threat of
scattered thunderstorms capable of locally heavy rainfall with some
training prospects within the confines of the quasi-stationary
boundary. The QPF footprint is a shotgun of small QPF maxima
reflective of the potential with less of any organized threat and
more of a widespread convective pattern that favors some locally
greater impacts, but remaining on the low to middle grounds of the
MRGL threshold. The one area of note for a potentially more
impactful setup is across the Central Mid Atlantic where a stronger
shortwave will advect northeast out of the Carolina's with
increased upper forcing traversing the DC/Baltimore metro area
during the middle of peak diurnal instability. Recent deterministic
output is a bit more robust compared to recent forecasts and is in
agreement with the ML output based within the GFS Graphcast and
ECMWF AIFS. It will be interesting to see the trends as we move
into the CAMs window because there could be a targeted SLGT risk
within the urban corridor if the signal holds. A MRGL risk is in
effect, but will be monitoring closely.

Kleebauer


Day 3
Valid 12Z Tue Jul 23 2024 - 12Z Wed Jul 24 2024

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS OF
TEXAS...

...Southern Plains...

A repeat of heavy convection across TX is forecast as the quasi-
stationary front within deep moisture anomalies remains parked
across much of Central and Eastern TX. Latest ensemble bias
corrected QPF is signaling an additional 2-3" possible within the
I-35 corridor with some scattered heavy rain signals all the way
back into the Central RGV from Del Rio down towards Laredo. Weak
mean storm motions and rates likely pushing 2-3"/hr will allow for
more significant flooding potential over areas that will have been
hit the prior period. In fact, 48-hr QPF could top 6" in spots
within the two successive periods which would allow for significant
issues to arise if it falls across the I-35 corridor. A SLGT risk
was maintained and expanded across the western flank of the risk
area to account for trends in the ensemble QPF footprint and better
instability fields located out towards the RGV. If the previous
period ends up with more significant impacts, this could lead to an
upgrade in the forecast risk over portions of Central TX.


...Southern Rockies and Southwest...

Monsoonal convection will encompass much of the Southwest U.S with
primary coverage in the Great Basin as the mid-level ridge pattern
shifts focus to the west of the Four Corners. Modest moisture
anomalies and relatively formidable instability across much of the
region will allow for scattered thunderstorms with isolated heavy
rain cores that could spell issues if they fall along complex
terrain, burn scars, urban footprints, and slot canyons. A MRGL
risk is in effect across much of the climatologically favored
areas in the Southwestern Monsoon.

...Upper Midwest...

Shortwave trough moving through the Great Lakes will allow for the
initiation of organized convection as it pivots through the region.
Modest instability and moisture anomalies in the confines of the
Lakes will lead to some scattered heavy rain signals as the
disturbance traverses the area. The progressive nature of the
system will limit widepsread flash flooding concerns, but a few
isolated heavier cores could pose some issues for more urbanized
areas across Northern and Central WI into the Michigan UP. A low-
end MRGL is in effect for the above area.

Kleebauer

Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5wYO0Qg-nf2zBennJJM14qRe-ja4ilU6NcKcszeevB_s= fki5WQfl2haoS6S1PzkleocmkrOq79PmvtBGDE3FM0hpmkk$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5wYO0Qg-nf2zBennJJM14qRe-ja4ilU6NcKcszeevB_s= fki5WQfl2haoS6S1PzkleocmkrOq79PmvtBGDE3FPCbhygA$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5wYO0Qg-nf2zBennJJM14qRe-ja4ilU6NcKcszeevB_s= fki5WQfl2haoS6S1PzkleocmkrOq79PmvtBGDE3FEl_lGkA$=20

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FOUS30 KWBC 220340 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
1140 PM EDT Sat Sep 21 2024

Day 1
Valid 0328Z Sun Sep 22 2024 - 12Z Sun Sep 22 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE SOUTHERN HIGH PLAINS...

03Z Special Excessive Rainfall Discussion...
Special Excessive Rainfall Outlook sent at 0324Z to include a
Marginal risk area over parts of southeast Pennsylvania and the
Delmaeva due to a cluster of storms over Pennsylvania that were=20
producing rainfall rates approaching 2 inches per hour in=20
spots...with convection expected to continue building southeastward
along a warm/moist axis. Refer to Mesoscale Precipitation=20
Discussion 1041 for additional details.

Also made a few minor adjustments to the Southern Plains based on
latest satellite and radar trends. Overall...changes were minor.

Bann

...New Mexico into Texas/Oklahoma Panhandles...

...0100 UTC Update...
Few changes made to the Slight and Marginal Risk areas based on the
latest observational and mesoanalysis trends, along with the recent
HRRR and HREF guidance.

The large- scale flow across the southern Great Basin will
continue to draw moisture northward at the low levels while
becoming increasingly diffluent aloft in response to the approach
of an upper low moving across the Four Corners this morning.
Precipitable water values are forecast to exceed 1.5 inches across
parts of West Texas by late afternoon while the right entrance
region of an upper level jet rounds the base of an upper trough and
tracks over the region. This combination should help support
multi-cell storms capable of producing isolated rainfall rates of
an inch or more and storm total rainfall amounts in excess of 2
inches over portions of northeastern New Mexico into the Texas
Panhandle during the afternoon or evening hours with an associated
risk of flash flooding. 12Z CAMs have honed in on northeastern NM
into the OK/TX Panhandles while decreasing any heavier rainfall
threat north of the KS border, and have thus trimmed the northern
part of the MRGL and SLGT risk areas a bit.

...Mid-Atlantic...
Non-zero threat of isolated/urban flash flood threat for northern
and central PA, along with central-southern VA this evening with
clusters of convection moving slowly to the south. Convective
trends should be on the downswing between 01-03Z given the negative
MUCAPE trends. Nevertheless, MLCAPEs around 1000+ J/Kg early, owing
partially to mid level lapse rates ~6.5 C/KM, along with transient
upper shortwave energy/left exit region upper jet forcing will
maintain a non-zero flash flood threat through midnight. Given the
latest guidance, progression of the convection, and mesoanalysis
trends, opted to not hoist a Marginal Risk for what will be a
short term, non-zero (widely localized) flash flood risk.

Hurley/Fracasso/Bann

Day 2
Valid 12Z Sun Sep 22 2024 - 12Z Mon Sep 23 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE MID MISSISSIPPI VALLEY TO THE SOUTHERN HIGH PLAINS...

20Z update...Nudged the Slight Risk area over MO/IL southward per
recent 12Z guidance (and typical north bias in convective axes).
Otherwise, CAM guidance supports maintaining the SLGT over TX and
the larger MRGL outline encompassing both areas, within the broad
SW flow aloft and near/ahead of the frontal boundary.

Fracasso

The focus for areas of heavy rainfall will continue to be along a
plume of deeper moisture...precipitable water values generally at
or above 1,75 inches...from the western portion of Texas
northeastward to where it begins to encounter a cold front moving
in from the northern United States. An upper level shortwave trough
over the central and southern Rockies on Sunday morning will eject
eastward during the day...aiding the formation of storms over parts
of western Texas capable of heavy downpours around the time of
maximum heating. Farther to the east...model guidance tends to
generate at least some convection capable of producing isolated 2
to 3 inch rainfall amounts over portions of Missouri as moisture
flux convergence occurs ahead of a cold front pushing southward.
Mesoscale guidance...available through the first 12 hours of the
Day 2 period for the overnight EROs...does show low-end potential
for 2 inch per hour rates embedded within a broader area where
probabilities of 1 inch per hour rates are on the order of 10 to 25
pct. There was already a Slight Risk introduced here and only
needed a bit of realignment to fit the latest guidance.

Bann

Day 3
Valid 12Z Mon Sep 23 2024 - 12Z Tue Sep 24 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER A PORTION OF
THE MISSISSIPPI VALLEY EASTWARD INTO THE OHIO VALLEY...

20Z update...Maintained the MRGL outline for the MS to Ohio Valley
region, with a shift a bit southwestward per trends in the guidance
favoring a bit slower progression. ML first guess fields still show
just a MRGL for now, with more clarity (hopefully) with some CAM
guidance in the next update or two.

Fracasso

As the large scale upper trough continues to move eastward on
Monday...the plume of available moisture gets elongated and the
moisture flux along the front becomes less well defined. There will
be some broader upper support along the front which will have taken
on a more east-west orientation...so there is at least some
potential for problems from run off with 1 to 2 inches or rainfall
over portions of Illinois into Indiana. But with convection
expected to become increasingly elevated and with flash flood
guidance tending to be 2.5 inches per hour or greater...will
maintain a Marginal Risk area for now and evaluate the need for an
upgrade if rates/amounts pick up in later model cycles.

Bann


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!9VVUw4syyZeCI8ZDlbZo38i_jMpb1LYbBpFGLXCq4EPv= yMlHBiS1vSfHjNm6oR-LkFgfO_JpgbXI8dJCiy9YNljfbc0$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!9VVUw4syyZeCI8ZDlbZo38i_jMpb1LYbBpFGLXCq4EPv= yMlHBiS1vSfHjNm6oR-LkFgfO_JpgbXI8dJCiy9Yukww_Nw$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!9VVUw4syyZeCI8ZDlbZo38i_jMpb1LYbBpFGLXCq4EPv= yMlHBiS1vSfHjNm6oR-LkFgfO_JpgbXI8dJCiy9YaKraiGg$=20

=3D =3D =3D
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FOUS30 KWBC 152201 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
501 PM EST Sat Feb 15 2025

Day 1
Valid 2147Z Feb 15 2025 - 12Z Sun Feb 16 2025

...THERE IS A HIGH RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE
LOWER MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS...

2147Z Update...The Moderate Risk was extended farther into
southwest Virginia to account for their flash flood emergencies.

Recent radar/satellite imagery late this afternoon shows a
continued axis of training moderate to heavy rainfall from Arkansas
across southern IL into portions of KY and southwest VA. Inflow at
850 hPa is from the west-southwest at 50+ kts and was quasi-
parallel on the cool/overrunning side a set of warm fronts in an
area of low- to mid-level frontogenesis. Expectation is for the
flow to remain parallel in nature of the above frontal alignment.
Precipitable water values are 1.3-1.5" and flash flood guidance is
quite depressed, approaching zero, within an area of completely
saturated soils. The various Moderate and High Risk areas remain
supported, given the above. The best instability remains across
portions of the Mid- South, where mesocyclone formation and
training convective bands are most likely. A variety of new flash
flood warnings are covering that scenario from central AR into the
Bootheel of MO.

Significant rainfall remains in the offing for a large portion of
the Lower Mississippi and Ohio Valleys. Expect a continued large
expanse of flash flood and areal flood warnings into tonight with
more flash flood emergencies possible. Confidence remains very high
for potential life- threatening flash flooding occurring in the
above areas.

Roth/Kleebauer



Day 2
Valid 12Z Sun Feb 16 2025 - 12Z Mon Feb 17 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL IN PORTIONS OF THE MID-ATLANTIC...

20Z Update: The main change from the previous forecast was a
further expansion of the MRGL risk to the west and southwest across southwestern VA and northwestern NC where trends within the 12z
HREF highlights lingering convective schemes over the terrain in
the first 3-6 hr window of D2, an area that will be well-primed and
likely experiencing ongoing flood concerns from the previous
period. Already some significant flooding within the far southwest
section of VA due to the combination of persistent mod/heavy
rainfall and snow melt. HREF 1"/6-hr probs are between 50-70% with
much of the precip falling in a few hrs within the short term
window 12-18z Sun. Progressive nature of the precip will aid in
maintaining a very low-end prob for flash flooding for other areas
downstream within the Mid-Atlantic, including the metro corridor
from Richmond to Boston. Still maintaining non-zero probs for those
areas across the Megalopolis, but prob fields are not signaling
much in the way of confidence to expand the risk area further
north, so maintained continuity from previous forecast.

Kleebauer

..Previous Discussion..

A Marginal Risk was maintained across portions of the Mid-Atlantic,
mainly as a reflection of the potential for brief, heavy rains
advancing along the cold front moving across the region early in
the period. While these storms are expected to be progressive,
with widespread additional heavy totals not expected, moist soils
further saturated by rain in the previous period may encourage
isolated flash flooding responses, especially across portions of
southwestern to central Virginia.

Pereira

Day 3
Valid 12Z Mon Feb 17 2025 - 12Z Tue Feb 18 2025

The probability of rainfall exceeding flash flood guidance is less
than five percent.

Pereira/Kleebauer

Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!710iV4297ODWJ8yft9NEU4gZRN1cSI3AsBSSYBneuw22= UMatJilvy9CpE7Iao3RMbbpoZ-yITgITOIVFgDTFu9SgnbE$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!710iV4297ODWJ8yft9NEU4gZRN1cSI3AsBSSYBneuw22= UMatJilvy9CpE7Iao3RMbbpoZ-yITgITOIVFgDTFr9n8d_k$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!710iV4297ODWJ8yft9NEU4gZRN1cSI3AsBSSYBneuw22= UMatJilvy9CpE7Iao3RMbbpoZ-yITgITOIVFgDTFp12RExk$=20

=3D =3D =3D
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FOUS30 KWBC 152203 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
503 PM EST Sat Feb 15 2025

Day 1
Valid 2147Z Sat Feb 15 2025 - 12Z Sun Feb 16 2025

...THERE IS A HIGH RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF THE
LOWER MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS...

2147Z Update...The Moderate Risk was extended farther into
southwest Virginia to account for their flash flood emergencies.

Recent radar/satellite imagery late this afternoon shows a
continued axis of training moderate to heavy rainfall from Arkansas
across southern IL into portions of KY and southwest VA. Inflow at
850 hPa is from the west-southwest at 50+ kts and was quasi-
parallel on the cool/overrunning side a set of warm fronts in an
area of low- to mid-level frontogenesis. Expectation is for the
flow to remain parallel in nature of the above frontal alignment.
Precipitable water values are 1.3-1.5" and flash flood guidance is
quite depressed, approaching zero, within an area of completely
saturated soils. The various Moderate and High Risk areas remain
supported, given the above. The best instability remains across
portions of the Mid- South, where mesocyclone formation and
training convective bands are most likely. A variety of new flash
flood warnings are covering that scenario from central AR into the
Bootheel of MO.

Significant rainfall remains in the offing for a large portion of
the Lower Mississippi and Ohio Valleys. Expect a continued large
expanse of flash flood and areal flood warnings into tonight with
more flash flood emergencies possible. Confidence remains very high
for potential life- threatening flash flooding occurring in the
above areas.

Roth/Kleebauer



Day 2
Valid 12Z Sun Feb 16 2025 - 12Z Mon Feb 17 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL IN PORTIONS OF THE MID-ATLANTIC...

20Z Update: The main change from the previous forecast was a
further expansion of the MRGL risk to the west and southwest across southwestern VA and northwestern NC where trends within the 12z
HREF highlights lingering convective schemes over the terrain in
the first 3-6 hr window of D2, an area that will be well-primed and
likely experiencing ongoing flood concerns from the previous
period. Already some significant flooding within the far southwest
section of VA due to the combination of persistent mod/heavy
rainfall and snow melt. HREF 1"/6-hr probs are between 50-70% with
much of the precip falling in a few hrs within the short term
window 12-18z Sun. Progressive nature of the precip will aid in
maintaining a very low-end prob for flash flooding for other areas
downstream within the Mid-Atlantic, including the metro corridor
from Richmond to Boston. Still maintaining non-zero probs for those
areas across the Megalopolis, but prob fields are not signaling
much in the way of confidence to expand the risk area further
north, so maintained continuity from previous forecast.

Kleebauer

..Previous Discussion..

A Marginal Risk was maintained across portions of the Mid-Atlantic,
mainly as a reflection of the potential for brief, heavy rains
advancing along the cold front moving across the region early in
the period. While these storms are expected to be progressive,
with widespread additional heavy totals not expected, moist soils
further saturated by rain in the previous period may encourage
isolated flash flooding responses, especially across portions of
southwestern to central Virginia.

Pereira

Day 3
Valid 12Z Mon Feb 17 2025 - 12Z Tue Feb 18 2025

The probability of rainfall exceeding flash flood guidance is less
than five percent.

Pereira/Kleebauer

Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5PQF869oRDjn9fMbLVudzrbFAJOTCfw6qaosg2Bk08_N= cTy08SBwuDQRx0nVN-M_rNsDm9VoQOU7K5bR5jg2mG647fg$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5PQF869oRDjn9fMbLVudzrbFAJOTCfw6qaosg2Bk08_N= cTy08SBwuDQRx0nVN-M_rNsDm9VoQOU7K5bR5jg2if8A-cY$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5PQF869oRDjn9fMbLVudzrbFAJOTCfw6qaosg2Bk08_N= cTy08SBwuDQRx0nVN-M_rNsDm9VoQOU7K5bR5jg2VKxVk70$=20

=3D =3D =3D
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FOUS30 KWBC 062219 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
519 PM EST Thu Feb 6 2025

Day 1
Valid 2218Z Thu Feb 06 2025 - 12Z Fri Feb 07 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF CALIFORNIA AND THE OHIO VALLEY...

...California...
For a more detailed discussion please refer to Mesoscale
Precipitation Discussion (MPD) 23 that is valid until 03z this
evening.

After a one day break another system is forecast to move into CA
today and Thursday night. Not an AR but rather a compact, dynamic
system with a vigorous mid level shortwave and strong left exit
region upper level jet forcing. These dynamics should support a
short duration period of enhanced rainfall rates, although the
quick forward motion of the system will limit overall rainfall
magnitudes. Given the low-level ageostrophic response ahead of the
upper level jet streak, the latest (00Z) GEFS output shows a quick
uptick in southwesterly 850-700 mb moisture transport, peaking
between 3-4 standard deviations above normal across the central 2/3
of CA Thursday afternoon and evening. Recent model runs continue
to show 1-2+ inches falling mostly within 12 hours, with localized
amounts of 3+ inches over the coastal ranges and Sierra foothills
per the latest high-res guidance. Given the saturated conditions
and brief potential for higher rates (0.35+ in/hr) beginning around
21Z along the coast and by 00Z farther inland, this may result in
localized runoff issues, especially over burn scars across Santa
Barbara, Ventura, and Los Angeles counties.

Gallina/Hurley


...TN-OH Valleys into the Western Appalachians...
Another round of locally heavy rain has begun to occur across
portions of KY, TN, WV and far western VA- NC near and ahead of an
approaching cold front and near the base of a broad shortwave
transiting the Great Lakes. While precipitable water values are
run of the mill -- 0.75-1.25" -- the coolness of the atmosphere is
leading to significant saturation, which is aiding precipitation
efficiency. MU CAPE of 500-1000 J/Kg is being tapped by elevated
activity across west- central KY while similar values of ML CAPE
are being utilized by more surface based convection closer to the
front. The expectation given the above is for hourly rain totals to
1.5" and local amounts of 3" being possible, which is problematic
given the flash flood guidance values being depressed, roughly in
the 1-1.5" in 3 hour range. Some of this region is still likely
more sensitive than normal to additional heavy rainfall given the
1-3" that fell over the past 24 hours. Overall, a widely scattered
to scattered flash flood risk appears to exist. Mesoscale
Precipitation Discussion #24 covers the expectations through 04z
for portions of KY, northern TN, and southwest VA.

Roth/Hurley


Day 2
Valid 12Z Fri Feb 07 2025 - 12Z Sat Feb 08 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Pereira


Day 3
Valid 12Z Sat Feb 08 2025 - 12Z Sun Feb 09 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Pereira


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5SE4mgNYYbuYPOXYezE6X0oxfMIlpZ-SsPD3EGy7vXQG= qR9EnQTEA38qR_zvHt6KUKkDcFVsb5QY5gsmnjddvsPO1iA$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5SE4mgNYYbuYPOXYezE6X0oxfMIlpZ-SsPD3EGy7vXQG= qR9EnQTEA38qR_zvHt6KUKkDcFVsb5QY5gsmnjdd_IC4vrs$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5SE4mgNYYbuYPOXYezE6X0oxfMIlpZ-SsPD3EGy7vXQG= qR9EnQTEA38qR_zvHt6KUKkDcFVsb5QY5gsmnjddkmNcFdM$=20

=3D =3D =3D
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FOUS30 KWBC 070844 AAA
QPFERD

Excessive Rainfall Discussion...UPDATED
NWS Weather Prediction Center College Park MD
344 AM EST Fri Mar 7 2025

Day 1
Valid 12Z Fri Mar 07 2025 - 12Z Sat Mar 08 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Bann

Day 2
Valid 12Z Sat Mar 08 2025 - 12Z Sun Mar 09 2025

...A MARGINAL RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE
CENTRAL GULF COAST...

There will be an increasing chance for showers and thunderstorms to
organize and become capable of producing rainfall rates in the 1 to
2 inch per hour range along portions of the central Gulf coast on
Saturday and Saturday night.

A fairly potent upper low will be making its way from the Southwest
U.S. into the Southern Plains by early Sunday morning. South to=20 southwesterly low level flow ahead of the mid- level energy will=20
start to draw moisture northward...with precipitable water values=20
increasing into the range between 1.50 and 1.75 inches by Saturday=20 afternoon...although present indications are that the higher=20
rainfall rates probably do not develop until the better upper level
support arrives and a well- defined cold front makes approaches=20
the coast later in the day.

The 07/00Z suite of QPF guidance still focused parts of the Gulf
coast for mainly a low-end risk of excessive rainfall...which mirrored
the WPC deterministic QPF preference which gave least
consideration to the more northerly position of the GFS QPF
compared with other operational model runs...and offered strong
support to the placement of yesterday's Day 3 ERO.
Consequently...only minor changes were needed.

Bann

Day 3
Valid 12Z Sun Mar 09 2025 - 12Z Mon Mar 10 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE SOUTHEAST U.S....

The potent shortwave trough that brings the risk of excessive
rainfall along the Gulf coast on Day 2 will continue tracking
eastward from the Southern Plains towards the Florida panhandle or
southern Alabama by early Monday morning.. Moist southwesterly=20
flow ahead of the system will have drawn an airmass with=20
precipitable water values in excess of 1.5 inches over portions of=20
the northern Florida peninsula and adjacent parts of Georgia. The=20
WPC deterministic QPF forecaster still gave less weight to the=20 GFS...resulting in little need to make more than some cosmetic=20
changes to the placement of yesterday's Day 4...before the bulk of=20
the rainfall from this system moves offshore.

Bann


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!93RCxY3FS9-pOIdAp81v0IHlXi5PL_qMwGUX-ucLCC8X= _8GQFEJhrGQdVuWe29bwHdClmC8z8bAGXHwbJ5j9SsEmKx0$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!93RCxY3FS9-pOIdAp81v0IHlXi5PL_qMwGUX-ucLCC8X= _8GQFEJhrGQdVuWe29bwHdClmC8z8bAGXHwbJ5j9aS9mnDM$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!93RCxY3FS9-pOIdAp81v0IHlXi5PL_qMwGUX-ucLCC8X= _8GQFEJhrGQdVuWe29bwHdClmC8z8bAGXHwbJ5j9VcgECo4$=20

=3D =3D =3D
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