AWUS01 KWNH 090852
FFGMPD
WIZ000-MNZ000-IAZ000-091435-

Mesoscale Precipitation Discussion 0884
NWS Weather Prediction Center College Park MD
452 AM EDT Sat Aug 09 2025

Areas affected...northern IA into southeastern MN and western WI

Concerning...Heavy rainfall...Flash flooding likely

Valid 090851Z - 091435Z

SUMMARY...The threat for flash flooding is expected to increase
this morning from northern IA into southeastern MN and western WI.
Areas of training with rainfall rates in the 1-3 in/hr range are
expected with 2 to 4+ inch totals through 14Z.

DISCUSSION...Regional radar imagery at 0830Z showed an expanding
cluster of thunderstorms just west of Minneapolis with outflow
oriented ENE to WSW moving into the downtown portion of the city.
This cluster has produced rainfall rates of 0.5 to 1.5 inches in
15-30 minutes from training over Wright County and a short term
flash flood threat appears likely into the Twin Cities over the
next hour or so.

Elsewhere across MN and IA, thunderstorm activity was fairly
limited in coverage but was beginning to trend upward ahead of a
large closed low over the Saskatchewan/U.S. border, steadily
advancing eastward with downstream ascent over the eastern Dakotas
into MN. At the surface, a slow moving (nearly stationary) front
was analyzed over west-central MN, from north to south, with a
secondary cold frontal surge with notable dewpoint falls to its
west across the Red River Valley. Ascent ahead of the large mid to
upper-level low, including upper level divergence and diffluence
tied to the right-entrance region of a 100 kt jet over ND, will
act to further increase thunderstorm coverage over the next 3-6
hours over the region.

As the ongoing cluster of thunderstorms to the west of MSP
continues to shift eastward into northwestern WI over the next
couple of hours, expansion of a second thunderstorm cluster is
expected from northwestern IA into southeastern MN ahead of the
cold front within a zone of low level moisture transport fed by
30-40 kt southerly 850 mb winds. This area of thunderstorms is
expected to follow the deeper layer mean flow toward the
northeast. As the secondary cold front reaches northwestern IA
near/just after 12Z, another round of thunderstorms is expected to
develop over northwestern IA with similar northeastward
advancement.

The pattern will favor repeating rounds of thunderstorms with
embedded periods of training which are likely to generate some
areas of flash flooding with rainfall rates of 1-2 in/hr, perhaps
as high as 2-3 in/hr within the anomalously moist/unstable airmass.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6g9HpouFQjdOui-ds94a79wlXIembMAjSiYu1hcWO2YvhV7RdE11DohMr9C4_akR4YJo= oBn5VaZbPvyvcQBKjoEMdpQ$ for graphic product...

ATTN...WFO...ARX...DLH...DMX...FSD...GRB...MKX...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 46119202 45699032 44538980 43709015 42849193=20
42089495 42709620 43599584 45149406=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 091431
FFGMPD
MIZ000-WIZ000-MNZ000-IAZ000-091900-

Mesoscale Precipitation Discussion 0885
NWS Weather Prediction Center College Park MD
1031 AM EDT Sat Aug 09 2025

Areas affected...Northern Iowa, Southeastern Minnesota, and
Central Wisconsin

Concerning...Heavy rainfall...Flash flooding likely

Valid 091430Z - 091900Z

SUMMARY...Local rain rates to 2.5 inches per hour are occurring
within a very slow moving line of storms. Some of the hardest hit
areas could see 6" of rain over the next 4-6 hours. Flash flooding
likely.

DISCUSSION...A very slow moving front draped from central Iowa
into Wisconsin, with an attendant low along it, has become the
forcing for numerous showers and thunderstorms across a portion of
the upper Midwest this morning. The storms are very slow moving,
and while aligned along the front, the storms aren't really
training, but simply moving so slowly that they have time to drop
multiple inches of rain. The front has nearly stalled because the
upper level low and its cold front to the north have turned
northeastward, and thus are moving parallel to the front,
resulting in very little push for the front to continue eastward.
As is typical, PWATs with the convection have been increasing
according to SPC Mesoanalysis, with a stripe over 2 inches along
and immediately ahead of the front. While there remains some CIN
around, MUCAPE has been increasing, now over 2,500 J/kg. The
instability this afternoon should increase to over 4,000 J/kg
ahead of the front, supporting any storms easily maintaining the
capability of 2+ inch per hour rainfall rates.

Meanwhile, a weakening overnight LLJ is surging incredible amounts
of instability and moisture northward ahead of the fronts. The LLJ
is weakening due to typical daytime heating disrupting the
otherwise laminar southerly flow through convection. This
weakening of the inflow should allow convection to become more
isolated and gradually weaken into the afternoon, but this may
take a while. CAMS guidance has been poorly resolving the coverage
and intensity of thunderstorms thus far, but the HRRR has been
coming into line with subsequent resolving of the current
conditions. The HRRR suggests the storms very slowly move east
into the early afternoon, as the line weakens. The storm motion
should increase later this afternoon as the storms try to leave
the front and follow the increasing instability during peak
heating.

Wegman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7itMHL4WR7SAQBC9_juyOgOPwvUvV91N4FQxaCix6E7cnrOEArMHifflf2QCcX-1ewd7= EnXZduXiC1MNoiAh0kndJR4$ for graphic product...

ATTN...WFO...ARX...DLH...DMX...DVN...GRB...MKX...MPX...MQT...

ATTN...RFC...MSR...NWC...

LAT...LON 46118880 45708843 44918804 44588800 43788939=20
43169052 42339189 41649329 41799436 42449488=20
43079463 43659418 44379297 44479274 44579223=20
44989117 45349035=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 091941
FFGMPD
SCZ000-FLZ000-GAZ000-100140-

Mesoscale Precipitation Discussion 0886
NWS Weather Prediction Center College Park MD
340 PM EDT Sat Aug 09 2025

Areas affected...SC Pee Dee/Lowcountry...Far Eastern
GA...Northeast FL

Concerning...Heavy rainfall...Flash flooding possible

Valid 091940Z - 100140Z

SUMMARY...Bands of heavy showers and thunderstorms should tend to
increase in coverage over the next few hours. Very heavy rainfall
rates will be likely, which will pose a threat for at least some
urban flash flooding/inundation concerns.

DISCUSSION...The latest GOES-E IR satellite imagery shows a
general expansion of cooling convective tops just offshore of the
Southeast coastline, with radar and surface data showing a general
westward advance of the shower and thunderstorm activity.

Very moist low-level cyclonic flow along the coast and extending
offshore in vicinity of a front should help maintain at least
disorganized convection over the next several hours which will
further be aided by the pooling of moderate instability. MLCAPE
values along the coast are near 1000 J/kg, and there is a fair
amount of frictional convergence noted along the coast which is
further supporting the potential for convective bands to at least
focus near and just inland of the SC/GA coastline. Areas of
northeast FL will tend to have a bit more of an inland diurnal heating/instability focused threat for slow-moving areas of
convection within the cyclonic low-level flow regime.

PWs of 2.2 to 2.4 inches are in place, and thus indicative of a
very tropical environment. This moisture along with the
instability should favor rainfall rates capable of reaching 2 to 3
inches/hour with these bands of convection, and some localized
cell-training concerns will be possible which could foster some
spotty totals of 3 to 5 inches by this evening. This is generally
supported by some of the recent HRRR guidance.

Given the rainfall potential, some urban flooding concerns will be
possible, and this threat may be locally exacerbated along the
immediate coast by the elevated tides associated with the
persistent onshore flow.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9fMEkmp4jfVjtWkbspGz2PMvdCGl6_1Mkh1PiDHh0rOBITh2-fNcfRMRdZ5KJJsrCvei= EcFrd3GwXrnj0ZuSLhMbk6w$ for graphic product...

ATTN...WFO...CAE...CHS...ILM...JAX...MLB...TBW...

ATTN...RFC...ALR...NWC...

LAT...LON 33917908 33447888 32258039 31228107 30388122=20
29228102 28968181 29578252 30388271 31308242=20
32538143 33218065 33757982=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 092330
FFGMPD
MOZ000-IAZ000-KSZ000-NEZ000-COZ000-100525-

Mesoscale Precipitation Discussion 0887
NWS Weather Prediction Center College Park MD
727 PM EDT Sat Aug 09 2025

Areas affected...Eastern CO...Much of Northern KS...Southern NE

Concerning...Heavy rainfall...Flash flooding possible

Valid 092327Z - 100525Z

SUMMARY...Increasing coverage of supercell thunderstorms with
gradual consolidation into an MCS is generally expected this
evening. Locally high rainfall rates and cell-merger activity will
pose at least an isolated threat for flash flooding.

DISCUSSION...The late-afternoon GOES-W visible satellite imagery
along with radar shows multiple supercell thunderstorm clusters
organizing and generally expanding in coverage across portions of
eastern CO.

This activity will be gradually advancing off to the east this
evening into a strongly unstable airmass pooled along and north of
a stationary front, with MLCAPE values currently on the order of
2000 to 4000 J/kg. The environment is strongly sheared and
conducive for additional supercell thunderstorm development which
will gradually set the stage for cell-mergers and consolidation of
activity into a larger scale MCS later this evening. Additional
factors supporting convective expansion is arrival of stronger
upper-level jet support/forcing from the central Rockies out ahead
of a digging upper-level trough over the Intermountain West.

A gradual increase in a southerly low-level jet is also forecast
this evening across the central Plains which will further aid
ascent across the High Plains in close proximity to the
aforementioned frontal zone. In fact, the latest HRRR guidance
supports a 40+ kt low-level jet nosing up across northern KS by
late this evening and this will likely support a more organized
level of convection advancing east from eastern CO and into areas
of northern KS and southern NE, which may include downstream
development ahead of the eastern CO MCS evolution.

Rainfall rates with the stronger supercells and with any
cell-merger activity may reach 2 inches/hour, and the increase in
moisture transport later this evening will encourage these higher
rates.

Some localized storm total amounts going through midnight may
reach 3 to 4+ inches. The antecedent conditions for most of the
region is on the dry side, but the cell-merger activity and
resultant rainfall totals may foster some isolated flash flooding
concerns.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6nAZzP8RQyE2TSvJixwe3jsJaDy_qDZyIA-f4vq5EdyRvFF57gTKgae_Pli53uy9J03i= o3hqrJvTg2b3OwZPU8bhLcI$ for graphic product...

ATTN...WFO...BOU...DDC...EAX...GID...GLD...ICT...LBF...OAX...
PUB...TOP...

ATTN...RFC...KRF...TUA...NWC...

LAT...LON 41419772 41299637 40429550 39209582 38749823=20
38469961 37980172 38120289 38740389 39960404=20
40690258 40970116 41199961=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 100047
FFGMPD
WIZ000-ILZ000-IAZ000-100645-

Mesoscale Precipitation Discussion 0888
NWS Weather Prediction Center College Park MD
845 PM EDT Sat Aug 09 2025

Areas affected...Southern WI...Northern IL...Eastern IA

Concerning...Heavy rainfall...Flash flooding likely

Valid 100045Z - 100645Z

SUMMARY...Increasing coverage of very heavy shower and
thunderstorm activity is expected by later this evening and going
into the overnight period. Slow-moving and locally
backbuilding/training convective cells are expected. This coupled
with high rainfall rates will promote areas of flash flooding,
some of which may be significant.

DISCUSSION...The latest surface analysis shows a well-defined
outflow boundary that is nearly stationary across portions of
northeast IA and across southern WI, with a rather significant
cold pool situated just to the north given the earlier convective
activity today.

A very moist and unstable airmass though has been pooling along
and just south of the boundary across eastern IA through northern
IL with MLCAPE values of 2500 to 3500+ J/kg. PWs are generally on
the order of 1.8 to 2.0 inches and generally suggestive of a
tropical environment. The latest CIRA-ALPW data shows rather
concentrated levels of moisture in the 850/500 mb layer and this
further supports the overall high PW environment.

This extremely favorable thermodynamic environment coupled with a
gradual increase in a south to southwest low-level jet along the
outflow boundary should support an uptick in convective
development by later this evening. Increasing coverage of showers
and thunderstorms should be most notable over southern WI where
isentropic ascent/cold pool interaction will be stronger, but
there is a likelihood for convection to develop and focus
eventually back into areas of northwest IL and eastern IA where
the nose of the low-level jet will be a bit stronger and thus
indicative of stronger speed convergence.

The level of moisture and instability that is in place coupled
with an increase in moisture transport overnight near this outflow
boundary will support extremely high rainfall rate potential that
could easily reach 2 to 3 inches/hour. The environment will
gradually become conducive for some backbuilding convective cells
as the low-level jet strengthens, and thus concerns for
cell-training will exist in time.

Recent HRRR and WoFS solutions have been supporting as much as 3
to 6+ inches of rain at least locally, with the heaviest rainfall
likely being over parts of southern to southeastern WI. Given the
environmental setup, these rainfall totals certainly seem
plausible, and locations such as Madison and Milwaukee may be
impacted by these heavier totals. In time overnight, areas as far
west as Dubuque, IA may see a similar threat.

Given the high rainfall rate and storm total potential, areas of
flash flooding are likely tonight, and some of this flash flooding
may be notably significant. This will include a threat for strong
urban flooding impacts.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9x0FEnoA_6QZM949Wm4Gt2aeSVTKLbVjsdtM1Gbw9D4fr4lH68LS4UvkPV28mRSw-Ly2= kmxAVJAoDoXZc5zj1ZImeZc$ for graphic product...

ATTN...WFO...ARX...DMX...DVN...LOT...MKX...

ATTN...RFC...MSR...NWC...

LAT...LON 43718920 43688789 43158714 42418740 41928839=20
41349106 41629218 42519239 43219127=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 100144
FFGMPD
SCZ000-GAZ000-100740-

Mesoscale Precipitation Discussion 0889
NWS Weather Prediction Center College Park MD
943 PM EDT Sat Aug 09 2025

Areas affected...Eastern GA...SC Lowcountry

Concerning...Heavy rainfall...Flash flooding possible

Valid 100140Z - 100740Z

SUMMARY...Locally concentrated bands of showers with high rainfall
rates will continue to be a threat going into the overnight hours
across coastal areas of eastern GA and SC. Additional urban
flooding impacts will be possible.

DISCUSSION...The latest GOES-E Proxy Visible satellite imagery
along with radar shows loosely focused bands of heavy shower and
thunderstorm activity continuing to focus along and offshore of
the GA/SC coastline.

Very moist low-level cyclonic flow along the coast and extending
offshore in vicinity of a front will remain in place going into
the overnight hours, and this coupled with the persistent pooling
of moderate instability and stronger convergence near the coast
should help to facilitate additional bands of convection that will
generally advance west or northwest into the coast.

MLCAPE values along the coast are still generally near 1000 J/kg,
with a very moist/tropical environment characterized by PWs of
2.25 to 2.5 inches. This has been favoring very high rainfall
rates of 2 to 3 inches/hour with some of the more recent activity
seen just southwest of Charleston.

Additional rainfall amounts of 3 to 5 inches cannot be ruled out
overnight with these bands of additional convection and especially
given concerns for localized cell-training. This has generally
been consistent with recent output from the HRRR guidance.

The additional rains along with wet antecedent conditions will
promote a threat for additional flash flooding overnight.
Generally this threat will tend to be localized, with the more
urbanized locations at greatest risk including Charleston and
Savannah.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5ShEmZAGhhooKBYAPpl1DzFOQntucjCoFiUZANbvfO1T8aywLR2xrska8DgO_2fYCzeL= ig0TxrCnazd4eABQw3O85_o$ for graphic product...

ATTN...WFO...CAE...CHS...ILM...JAX...

ATTN...RFC...ALR...NWC...

LAT...LON 33737940 33277908 32378013 31658088 31138149=20
31598203 32428159 33218065 33697982=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 100623
FFGMPD
WIZ000-ILZ000-MOZ000-IAZ000-KSZ000-NEZ000-101100-

Mesoscale Precipitation Discussion 0890
NWS Weather Prediction Center College Park MD
222 AM EDT Sun Aug 10 2025

Areas affected...southeastern NE into IA, southwestern WI and
northwestern IL

Concerning...Heavy rainfall...Flash flooding likely

Valid 100622Z - 101100Z

SUMMARY...Flash flooding will be likely over the next few hours,
especially in southeastern NE, but eventually affecting portions
of IA into southwestern WI and northwestern IL. Hourly rainfall of
2 to 3+ in/hr on a localized basis can be expected along with
storm total rainfall of 3 to 6+ inches through 12Z.

DISCUSSION...Radar imagery at 06Z showed a well-defined MCV over
southern NE, roughly 30 miles southeast of Hastings, tracking
toward the ENE. A damaging straight line wind event has been
occurring south of the NCV but warm advection to the north of a
long lived and sharply defined trough axis (located from
northeastern KS, across northern MO into western IL) was forming a
west-east axis of thunderstorms over southeastern NE. Overrunning
thunderstorms to the north of the surface trough (marked by a weak
temperature gradient) were oriented parallel to the track of the
MCV, setting up a favorable environment for training. SPC
mesoanalysis data from 05Z showed a region of 3000 to 3500+ J/kg
MLCAPE just ahead of the MCV over northeastern KS/southeastern NE
and eastward to the western IA/MO border.

Locally enhanced low level southerly flow just ahead of the MCV
will boost an already moderately strong 25-40 kt southwesterly 850
mb jet axis which was positioned from south-central KS into
southern IA and the WI/IL border. An expanding coverage of
thunderstorms, already blossoming from south-central IA into the
WI/IL border, should continue to evolve ahead of the advancing MCV
and broader overrunning southerly flow in place. Lift should be
aided by divergence within the right-entrance region of a
strengthening upper level jet (per RAP forecasts) from eastern SD
into MN. Given the forcing in place and high moisture (1.8 to 2.1
inch PWATs per SPC mesoanalysis), high rainfall rates are expected
within areas of training, easily capable of 1 to 2 inches in an
hour along with localized hourly totals of 2 to 3+ inches. While
there will be relative minimums of rainfall within the MPD threat
area, there is a broad threat with areas of flash flooding likely
embedded within, extending from southeastern NE into IA and the
WI/IL border.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!85PWg1_MzokC-iM-OYt6zKd_TqVuBxT0yf7-iwblAyyxGHRpmLL_cFAg3Ahwm4hdmGcj= sjNMYATtEa0Kn1k82Z6VaYQ$ for graphic product...

ATTN...WFO...ARX...DMX...DVN...EAX...FSD...GID...LOT...MKX...
OAX...TOP...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 43479076 43328954 42788927 41958956 41359035=20
40899245 40509436 40019614 39719768 40209823=20
40939786 41839645 42919319=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 100701
FFGMPD
WIZ000-100945-

Mesoscale Precipitation Discussion 0891
NWS Weather Prediction Center College Park MD
300 AM EDT Sun Aug 10 2025

Areas affected...southeastern Wisconsin, including Milwaukee metro

Concerning...Heavy rainfall...Flash flooding likely

Valid 100659Z - 100945Z

SUMMARY...An ongoing flash flood event over the city of Milwaukee
appears to be shifting to the north. However, areas of training
with locally high rainfall rates of at least 2-3 in/hr will
continue to impact portions of southeastern WI for another 1-2
hours with the threat beyond 09Z-10Z uncertain.

DISCUSSION...A focused heavy rainfall event has produced 7-9
inches of rain over the past 6 hours over the southwestern side of
Milwaukee (per area CWOP gauge reports) with areas of considerable
flash flooding. 20-25 kt of southwesterly flow at 850 mb has been
overrunning a nearly stationary outflow boundary located from Lake
County IL into south-central WI with Corfidi vectors suggestive of back-building and training.

SPC mesoanalysis data from 06Z indicated 1500+ J/kg MLCAPE
remained along the outflow boundary but the northward shift
appears to be related to the ongoing warm advection regime and
northward displacement of the elevated portion of the surface
outflow. This northward shift of the heaviest rainfall has been
accompanied by scattered thunderstorm development to the north and
west over portions of south-central WI. Expect areas of training
to continue over south-central to southeastern WI with localized
hourly rainfall of 1 to 3 inches along with continued areas of
flash flooding through at least 09Z.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!60lEz1r__BMNFL2DCk-hoCZeEAstkiISJSh7CZZdD_0oY09HB5hkJlWUqOHEKqox-rCx= eTdpHCytBnUbMRO1nYPfWyc$ for graphic product...

ATTN...WFO...ARX...GRB...MKX...

ATTN...RFC...MSR...NWC...

LAT...LON 43978812 43628722 42958700 42548745 42508828=20
42868907 43418981 43938940=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 101040
FFGMPD
WIZ000-ILZ000-MNZ000-IAZ000-101500-

Mesoscale Precipitation Discussion 0892
NWS Weather Prediction Center College Park MD
639 AM EDT Sun Aug 10 2025

Areas affected...IA into/across MS Valley and southern WI

Concerning...Heavy rainfall...Flash flooding likely

Valid 101039Z - 101500Z

SUMMARY...Scattered areas of flash flooding will continue to be
likely from central IA, east-northeastward into southern WI and
far northern IL. Training of heavy rain will produce peak hourly
rainfall of 2 to 3 inches along with additional totals of 2 to 4+
inches through 15Z.

DISCUSSION...Radar and infrared satellite imagery showed an MCV
over west-central IA, just ahead of another area of cyclonic
rotation along the NE/IA border...with movement toward the ENE.
Out ahead of these features, radar imagery showed scattered
thunderstorms extending eastward from the MCV into eastern IA,
southern WI and northwestern IL, to the north of a remnant outflow boundary/trough axis that extended from southern IA into northern
IL. Areas of embedded training contained MRMS-derived hourly
rainfall of 1-2 inches but with localized hourly rainfall of 2 to
3+ inches over the past 1-3 hours. Low level flow of 25-40 kt was
overrunning the boundary along with ascent ahead of the upstream
vortex and given a similar orientation of low level winds to the
somewhat weaker deeper layer mean wind, Corfidi vectors were
oriented into the inflow layer supporting areas of training and
backbuilding.

SPC mesoanalysis data from 10Z showed MLCAPE of 1000 to 2000+ J/kg
was in place from central IA into southern WI, along with PWATs
near 2 inches. Aloft, IA was within a favorable region for ascent
within the right-entrance region of a 110 kt speed max aloft over
northern MN. This environment is expected to sustain for at least
another 2-4 hours which will continue areas of training downstream
of the MCV/vorticity max's track toward the ENE. While the
mesoscale pattern across the Upper Midwest is rather complex at
the moment, there are indications that low level winds will begin
to weaken at least somewhat with the diurnal cycle through 15Z,
but some low level enhancement ahead of the MCV should remain.
Areas of training are expected to maintain a likely flash flood
threat through 14Z/15Z across the Upper Midwest with potential for
an additional 2 to 4+ inches in a few locations, but some
potential weakening of rainfall intensities will be possible near
15Z.

Otto

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!45upNSkFLCmx7YLR762l8qBIjUl1Gorhu4wKMpQZJa6H1Rm-uXMbobC97zOsQfl-S-cz= 9WJMlV3hwBw4Q1xP4BOZbHA$ for graphic product...

ATTN...WFO...ARX...DMX...DVN...GRB...LOT...MKX...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 44648957 44288792 43398776 42698882 41209061=20
41159441 42339497 44029263=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 101323
FFGMPD
WIZ000-101730-

Mesoscale Precipitation Discussion 0893
NWS Weather Prediction Center College Park MD
923 AM EDT Sun Aug 10 2025

Areas affected...Southeast Wisconsin

Concerning...Heavy rainfall...Flash flooding likely

Valid 101321Z - 101730Z

SUMMARY...Additional heavy rain with peak hourly rainfall of 1 to
2 inches will worsen ongoing flooding conditions in the Milwaukee
metro rest of this morning.

DISCUSSION...The leading edge of a shortwave trough has seen an
increase in heavy rainfall coverage over southeast Wisconsin.
Ample moisture inflow continues with low level SWly flow around
25kt at 850mb which will reinforce 2" PW. SBCAPE of 1500 J/kg will
allow further development as this leading edge crosses the rest of
southeast Wisconsin and the Milwaukee metro. Recent rainfall
estimates from KMKX are up to 2"/hr. Given the multiple rounds of
heavy rainfall over and north of the Milwaukee metro since last
evening with 3-8" measured, this additional heavy rain will
further exacerbate ongoing flooding conditions including
considerable threats.

Additional upstream activity currently along the eastern IA border
will need to be monitored for further impacts over southeast
Wisconsin later this afternoon. Recent HRRR guidance has that
activity shifting in this afternoon, but not the RRFS. Both of
these models do not have this current activity, so there remains
uncertainty for this afternoon. This will continue to be monitored.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6HD6ktknlqv7GKdy6MQuwBnkL3ihU7pjip7oXAoHanaus31G7wKUn4fVA7yhULJKbsA3= CCcyfgCJc4CKHAXC61k0FjE$ for graphic product...

ATTN...WFO...MKX...

ATTN...RFC...MSR...NWC...

LAT...LON 43398772 42818749 42498773 42628867 42928878=20
43318845=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 101804
FFGMPD
TXZ000-NMZ000-AZZ000-110003-

Mesoscale Precipitation Discussion 0894
NWS Weather Prediction Center College Park MD
203 PM EDT Sun Aug 10 2025

Areas affected...in and near portions of southeast AZ & NM

Concerning...Heavy rainfall...Flash flooding possible

Valid 101803Z - 110003Z

Summary...Showers and thunderstorms have begun to form as CIN
erodes across portions of southern AZ and southern NM. Hourly
rain amounts to 2" with local totals to 4" are possible.

Discussion...GOES-18 and GOES-19 Veggie Band imagery along with
trends in SPC mesoanalyses indicate CIN erosion across the region,
with isolated showers and thunderstorms developing. The region is
diffluent aloft at the base of an upper level trough and not far
to the northeast of an MCV approaching the central Mexico/AZ
border. Precipitable water values of 0.5-1.2" lie across the
region. ML CAPE has built quite a bit across southern AZ, with a
few areas with 2000+ J/kg. ML CAPE has been starting to build as
of late across NM, but isn't especially high at the present time
with a couple pockets of 500-1000 J/kg. Flow at 850 and 700 hPa
is west to northwest at 10-20 kts.

The mesoscale guidance shows a broadening and intensifying of
convection as time marches on this afternoon. ML CAPE could
increase an additional 1000 J/kg or so in areas where convection
holds off on visiting. The low-level flow should pin convection
across southeast AZ, making it difficult for activity in the
mountains to march into lower elevations. However, the incoming
MCV could cause convection to break out in lower elevations close
to the AZ/Mexico border. Convection should show a tendancy to
move east to southeast today. Given the moisture and building
instability, hourly amounts to 2" with local amounts to 4" where
cells manage to train or merge are considered possible. This
rainfall would be most problematic in urban areas, dry
washes/arroyos, and areas with burn scars.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!94KYcaNLnjjMZeQMQt0BVyGpfIlBVp6Lqy4mKIFxxazv_1BwhZJ4T4MNiV-G1iDXv7ei= AZFhsZw7PxJrz-fKNnJU7To$ for graphic product...

ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...

ATTN...RFC...FWR...STR...NWC...

LAT...LON 34680667 34370564 32470519 31650610 31150884=20
31131104 31881210 33561077 33990946=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 101853
FFGMPD
ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-110051-

Mesoscale Precipitation Discussion 0895
NWS Weather Prediction Center College Park MD
252 PM EDT Sun Aug 10 2025

Areas affected...in and near southern MO & southeast KS

Concerning...Heavy rainfall...Flash flooding possible

Valid 101851Z - 110051Z

Summary...Showers and thunderstorms developing across southeast MO
& northwest AR are expected to give way to new activity to the
west and northwest with time as CIN erodes and the low-level
inflow backs. Hourly amounts to 3" with local totals to 5"
possible.

Discussion...The combination of a surface trough and outflow
boundary have generated new convection with heavy rain across
portions of southeast MO. Precipitable water values are 1.75-2"
per GPS data. An ML CAPE gradient exists across portions of
southwest MO and southern KS, with 3000-4000 J/kg existing in the
instability pool in northeast OK. An area of effective bulk shear
of 25-40 kts is approaching from the west. CIN is eroding from
east to west across the region.

As CIN erodes, the primary foci for new convection are expected to
be along or near the outflow boundary in southeast KS and
southwest MO, from east to west as the 850 hPa inflow backs, as
well as closer to the incoming front which is through the Kansas
City MO/KS metro area. Given the ingredients in place, hourly
amounts to 3" with local totals to 5" are possible. Most of the
region has received minimal rainfall over the past week, so widely
scattered impacts are expected primarily with urban areas and
sections of the Ozarks.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_5H77Aq8zXpS8RmIiCDoopxKS8HuE6Av_pV5Rx5aVXm3tiRopfQ5ywJDPXDDiufxPNSd= AKNqX5R5iHaUtVofCMFBU14$ for graphic product...

ATTN...WFO...EAX...ICT...LSX...LZK...SGF...TOP...TSA...

ATTN...RFC...KRF...MSR...ORN...TUA...NWC...

LAT...LON 38919038 37439093 35729329 36419536 36789617=20
37259680 37879624 38679446=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 101925
FFGMPD
OKZ000-KSZ000-NEZ000-COZ000-NMZ000-WYZ000-110124-

Mesoscale Precipitation Discussion 0896
NWS Weather Prediction Center College Park MD
324 PM EDT Sun Aug 10 2025

Areas affected...portions of eastern CO

Concerning...Heavy rainfall...Flash flooding possible

Valid 101924Z - 110124Z

Summary...Showers and thunderstorms in the mountains of central CO
are about to emerge into the High Plains. Hourly amounts to 2.5"
with local totals to 4" are possible, which could lead to
scattered flash flood concerns.

Discussion...Showers and thunderstorms have been forming within an
environment with parallel low-level cloud bands across the
mountains of central CO. The upper level pattern is diffluent
ahead of a shortwave seen on water vapor imagery near the UT/CO/WY
border junction. Several overshooting cloud tops have been seen
on recent satellite imagery as the storms push towards the High
Plains. Upslope flow is strongest across northeast CO behind a
fine line/leading edge of expanding cumuliform clouds seen in
satellite imagery. Precipitable water values in the High Plains
are 1"+. ML CAPE is 1000-2500 J/kg, and increasing, while CIN
erodes regionally. Effective bulk shear is 35-40 kts.

Guidance indicates that thunderstorms should increase in coverage, organization, and intensity over the next several hours. While
the mean 850-400 hPa flow favors east-northeast movement, ML CAPE
gradients in the region would favor a more east to east-southeast
movement, which is more reflective of what's advertised within
mesoscale guidance. The concern is that a combination of
mesocyclones and merging convective clusters over could lead to
hourly rains as high as 2.5" and local totals to 4" as
precipitable water values pass 1.25" locally, which is exceedingly
high for any time of the year for the High Plains of CO. Pockets
of eastern CO have seen much above average rainfall this past
week, making the region sensitive, in spots. Urban areas would
also see problems should the higher end rainfall intensities move
through them. Scattered instances of flash flooding are possible.

Roth=20

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8ntetD5Chl_C1sDKfnUESsQYfAMfKpP2eBYC17BuaFdL6ApM2rySjVw-UvHOizqefSut= P9pT6nsPg-CTfjELeI9roDc$ for graphic product...

ATTN...WFO...ABQ...AMA...BOU...CYS...DDC...GLD...LBF...PUB...

ATTN...RFC...FWR...KRF...STR...TUA...NWC...

LAT...LON 41700553 41400346 40310142 37810172 36910265=20
36990529 37340612 38280630 39250565 40630600=20
41490619=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 102051
FFGMPD
WIZ000-ILZ000-IAZ000-110159-

Mesoscale Precipitation Discussion 0897
NWS Weather Prediction Center College Park MD
450 PM EDT Sun Aug 10 2025

Areas affected...portions of northeast IA & southwest WI

Concerning...Heavy rainfall...Flash flooding possible

Valid 102049Z - 110159Z

Summary...A small cluster of thunderstorms is trying to organize
as it moves east-northeast. Hourly amounts to 2" with local
totals to 4" are possible, which could lead to isolated to widely
scattered instances of flash flooding.

Discussion...A small convective cluster is trying to grow in
coverage and intensity as it moves east-northeast near a frontal
wave within a zone of 850 hPa wind confluence. Precipitable water
values are ~1.8". ML CAPE in its vicinity is 500-2000 J/kg and
CIN has been eroding from west-southwest to east-northeast.=20
Effective bulk shear of ~30 kts exists near this cluster.

The main concern would be that the cluster grows much further in
size and organization, as it is tracking into an area that
received 2-5" of rainfall during the past 24 hours. Hourly
rainfall up to 2" with local amounts to 4" appear possible, given
the ingredients available. Recent HRRR runs have had some concept
of future expectations in respect to locations impacted, and shows
the cluster evolving into a forward propagating line by 02z as
instability begins to decline, which would lessen the heavy rain
threat from that point forward.=20

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!59h50jJXWLg2iJFB7iHh5I8n89EYm-_79GRtp7SnrANmpVk4KgYAoPk5ejN_vK2pY826= bmbLc_uRbD121QYUoWAU1Aw$ for graphic product...

ATTN...WFO...ARX...DMX...DVN...MKX...

ATTN...RFC...MSR...NWC...

LAT...LON 43469082 43338986 42668996 42359046 42059228=20
42019248 42039296 42619254 43029200 43309145=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 102329
FFGMPD
TXZ000-NMZ000-AZZ000-110328-

Mesoscale Precipitation Discussion 0898
NWS Weather Prediction Center College Park MD
729 PM EDT Sun Aug 10 2025

Areas affected...portions of the TX Big Bend, Southern NM, &
Southern AZ

Concerning...Heavy rainfall...Flash flooding possible

Valid 102328Z - 110328Z

Summary...Showers and thunderstorms continue to hold on across the
region, and should do so for another several hours as they sink
towards Mexico. Until they wane tonight, hourly amounts to 2"
with local totals to 4" remain possible.

Discussion...Overshooting convective tops continue with the
convection across the TX Big Bend, southern NM, and southeast AZ.=20
The region is at the base of an upper level trough which is
providing difluence aloft. Precipitable water values are
0.9-1.3", fairly moist for sites with elevation. ML CAPE of
500-2000 J/kg remains across the region, and CIN is beginning to
return to the area.

The expectation is for thunderstorms with heavy rainfall to
continue sagging south and eastward, either dissipating on their
way to the US/Mexico border across AZ and NM weakening while
entering northwest TX or the TX Panhandle over the next four
hours. Guidance insists that thunderstorms with heavy rainfall
will hold on the longest near the southeast AZ border with Mexico.
Until they fade or cross into Mexico, hourly rain amounts to 2"
with local totals to 4" remain possible.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8thnvrDqD6DjnWZfoG4rYQ2wFQp3not2GtqVWxxqcwqvZLh3hf9iDN_y7OH-CRmD9mxJ= u7lg9PHZWgUz51x_UW9M9Ss$ for graphic product...

ATTN...WFO...ABQ...EPZ...FGZ...LUB...MAF...PSR...TWC...

ATTN...RFC...FWR...STR...TUA...NWC...

LAT...LON 34630190 31970233 29390382 30510587 31200706=20
31070872 31101118 31531240 32281265 33651106=20
34111005 34230857 33050638 32810420 34380358=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 110014
FFGMPD
WIZ000-ILZ000-IAZ000-110412-

Mesoscale Precipitation Discussion 0899
NWS Weather Prediction Center College Park MD
813 PM EDT Sun Aug 10 2025

Areas affected...southern WI

Concerning...Heavy rainfall...Flash flooding possible

Valid 110012Z - 110412Z

Summary...A convective cluster is moving briskly into southwest
WI, and along with additional thunderstorms forming in its
neighborhood, is threatening saturated areas of southeast WI.=20
Hourly rain amounts to 2" with local totals to 4" remain possible.

Discussion...A small thunderstorm cluster continues moving
east-northeast at 30 kts into southwest WI. Overshooting cloud
tops continue to be noted prior to sunset on Veggie Band imagery.=20 Precipitable water values are 1.75-2". An instability gradient
exists across southern WI which continues to edge northward to
sustain this cluster, with maximum values of 2000-2500 J/kg.=20
Effective bulk shear of 25-35 kts exists in the area.

As new cells are forming at its leading edge and to its east
closer to Chicago, there is little sign of the cluster trying to
arc out into a convective line yet. As soils were significantly
saturated across southeast WI with 5-14" of rain last night, they
would be sensitive to hourly amounts to 2" or local totals to 4"
wherever cells merge, train, or a mesocyclone manages to form and
track. The mesoscale guidance as a whole has been struggling
here, so left the category as Possible, but wherever the cluster
moves over saturated soils or urban areas, flash flooding would be
possible.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_mAknFSP-2poDSznjFXOEwP5IXOD6S7vqEEu-HVJg-wlsfsplz0g4eoeqRo3zefBiWSS= zC7lOa-ft_DYMDi01rtYSF8$ for graphic product...

ATTN...WFO...ARX...DVN...LOT...MKX...

ATTN...RFC...MSR...NWC...

LAT...LON 43758869 43538789 42538759 42278781 41989025=20
42019156 42629138 43349035=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 110054
FFGMPD
MOZ000-TXZ000-OKZ000-KSZ000-COZ000-NMZ000-110653-

Mesoscale Precipitation Discussion 0900
NWS Weather Prediction Center College Park MD
853 PM EDT Sun Aug 10 2025

Areas affected...eastern CO, western KS, near the KS/OK border, &
southwest MO

Concerning...Heavy rainfall...Flash flooding likely

Valid 110053Z - 110653Z

Summary...Thunderstorms are expected to bridge across from CO near
the KS/OK border over the next six hours. Hourly rain amounts to
3" with local totals to 5" over an increasingly broad scale should
allow for scattered to numerous instances of flash flooding
through 07z.

Discussion...Over the past 2-3 hours, thunderstorms have been
developing and congealing across portions of southwest MO and near
the eastern KS/OK border within and in the gradient north of an ML
CAPE pool of 3500 J/kg. CIN continues to erode here. A front
bisects the OK/KS border from east-northeast to west-southwest.=20
To the west, elevated thunderstorms continue their march across
eastern CO and far northeast NM. Precipitable water values of
1.25" in the High Plains to 2" farther east are seen near the
boundary. Effective bulk shear of 25-35 kts exist across the area.

As the low-level jet continues backing/edging to the west along
the OK/KS border, there should be a tendency for convection to
reform farther west from southwest MO and southeast KS. At the
same time, convection from CO is expected to move across western
KS. By 06z, either a merger of the two convective areas or
outflow from the activity currently across CO should lead to a
significant enhancement of heavy rainfall in or near southwest KS.
The 18z HREF advertises a nearly 20% chance of 5" through 06z,
and has similar odds of 8" in the 00z-12z time frame in far
southern KS. Meanwhile, the WoFS maximum is mostly south of the
eastern two-thirds of the OK/KS border, possibly due to ongoing
convection eroding the northern portion of the instability pool in
that area. Cell training, possible random mesocyclones, and cell
mergers are expected to lead to locally higher rain totals. With
a broadening scale of hourly rain amounts to 3" and local totals
to 5", and despite dryness over much of these region during the
past week, scattered to numerous instances of flash flooding are
expected overnight, which is expected to be underway before 07z.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!47i8czHkhAkAkTnNQFH3PKpQcV5Eqb9_Wj957hAp3ylTFyR884A4903Tssi3CKigeuv1= sy9FqW_kYowunYcsH1wepIM$ for graphic product...

ATTN...WFO...ABQ...AMA...BOU...DDC...EAX...GLD...ICT...LSX... OUN...PUB...SGF...TOP...TSA...

ATTN...RFC...KRF...ORN...TUA...NWC...

LAT...LON 40240316 39830139 38519954 38209793 38559547=20
38969282 37259262 36369516 35819960 35760028=20
35890207 36460351 38000446=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 110424
FFGMPD
WIZ000-ILZ000-IAZ000-110900-

Mesoscale Precipitation Discussion 0901
NWS Weather Prediction Center College Park MD
1223 AM EDT Mon Aug 11 2025

Areas affected...northern Illinois through central Wisconsin

Concerning...Heavy rainfall...Flash flooding possible

Valid 110423Z - 110900Z

Summary...Showers and thunderstorms expanding ahead of a shortwave
will likely train across parts of Wisconsin tonight. Rainfall
rates of 1-2"/hr at times will produce 1-3" of rainfall, and may
result in renewed flash flooding.

Discussion...The GOES-E IR imagery tonight shows expanding
convection evident via cooling cloud tops across parts of northern
Illinois and southern Wisconsin. These thunderstorms are generally
developing in response to the overlap of a shortwave analyzed by
the RAP and noted in the satellite imagery lifting across eastern
IA, with the slow veer of an 850mb LLJ analyzed by regional VWPs
to be 20-30 kts from the S/SW. This LLJ is drawing elevated PWs
northward, which were measured via the 00Z U/A soundings at DVN
and ILX to be above 1.9 inches, or well above the 90th percentile
for the date. These PWs are aligned with a ribbon of high MUCAPE
above 2000 J/kg, and as the LLJ continues around 30 kts the next
several hours, these robust thermodynamics will resupply an
environment favorable for heavy-rain producing convection.

Recent radar-estimated rainfall rates from KMKX have been as high
a 1.5"/hr, and the HREF neighborhood probabilities for 1"/hr
remain as high as 40% through around 09Z, while the HRRR
indicates an isolated potential for brief 3"/hr rain rates
(0.75"/15min). The strongest convection is likely during the next
few hours, primarily across southern WI, before the LLJ begins to
veer. This is also when the greatest height falls/PVA will occur
downstream of the shortwave as it lifts northeast, providing
enhanced ascent into the favorable thermodynamics.

There may be two areas of focused heavier rainfall, one across
central WI and a secondary maximum in southeast WI. Across central
WI, the LLJ nose will develop leading to enhanced convergence
before it begins to veer after 07Z. This suggests regenerating
cells in this region with enough support from thermodynamic
advection to produce repeating 1"/hr rain rates. With cells likely strengthening right along this convergent axis, rainfall could
reach 1-3" leading to isolated instances of flash flooding within
a narrow corridor.

Farther south in WI and into far northern IL, the greatest
isentropic ascent is likely, which will act into a plume of the
most intense MUCAPE. Here, propagation vectors collapse to around
5 kts and become aligned obliquely right of the mean wind
suggesting backbuilding cells and a higher training threat. Rain
rate probabilities also peak in this vicinity, and the HREF 6-hr
rainfall probabilities for 3" rise above 15%. Southern WI has also
experienced tremendous rain the past 24-hrs of 2-5", and in some
areas more than 9" of rain, leading to extremely vulnerable soils
such that any heavy rain could quickly lead to runoff and
instances of flash flooding.

Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_3v1zRJNRvp-j3FKUYPjRVhvGbxMCsh4UlA9MC-EWaAO33e92oTzGb6w6MjJBQ3xGOED= QYViyd1hxpt_9-5SRx_1Czs$ for graphic product...

ATTN...WFO...ARX...DVN...GRB...LOT...MKX...

ATTN...RFC...MSR...NWC...

LAT...LON 45258843 45058781 44668756 44198757 43318773=20
42818781 42348803 41878897 41819016 42209087=20
42559100 43419084 44409024 45008936=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 110517
FFGMPD
NCZ000-SCZ000-GAZ000-111115-

Mesoscale Precipitation Discussion 0902
NWS Weather Prediction Center College Park MD
116 AM EDT Mon Aug 11 2025

Areas affected...Coastal Georgia through Coastal Southeast North
Carolina

Concerning...Heavy rainfall...Flash flooding possible

Valid 110515Z - 111115Z

Summary...Heavy showers and isolated thunderstorms pivoting
onshore will continue overnight. Rainfall rates of 2-3"/hr are
likely, which through training could produce 2-3" of rain with
locally higher amounts. Flash flooding is possible.

Discussion...The regional radar mosaic this evening shows
expanding convection lurking just offshore to the east of the SC
and GA coasts. This convection is expanding in response to ascent
driven via strung-out vorticity aligned along the coasts combined
with increasing thickness diffluence noted in the mid-level
thickness fields. At the same time, 850-500mb winds are generally
from the E/SE around a mid-level trough axis, with recent 850mb
winds measured at KJAX and KCLX VWPS of 20-30 kts, more than twice
the mean wind, supporting additional ascent. This lift is
occurring into impressive thermodynamics characterized by PWs
measured by GPS of 2.3 to 2.4 inches, nearly the daily record for
the region, overlapping MUCAPE of 1000-3000 J/kg as analzyed by
the SPC RAP. Together, this is resulting in an expansion of heavy
rainfall with embedded thunderstorms, with impressive reflectivity
above 40dBZ identified near shore via the regional radar mosaic,
but also additionally farther offshore utilizing the satellite
GREMLIN product, with sufficient GLM lightning density to support
its output.

As onshore flow persists and forcing remains, convection should
expand and intensify through the night. As is typical with
nocturnal flare ups like as expected, the heaviest rainfall should
be confined to offshore and the immediate coast due to a rapid
dropoff in instability inland. The simulated reflectivity and
rainfall footprint from the available CAMs supports this
conceptual model, but with 850mb winds continuing to exceed the
mean wind, some inland push of heavier rainfall is possible.
However, the most intense rain rates, which have a 15-25% chance
of exceeding 2"/hr from the HREF, and may locally exceed 3"/hr at
times (15-min HRRR rainfall of 0.75") should remain along the
immediate coast. Despite storm motions of 10-15kts to the NW,
Corfidi vectors collapsed to 5 kts or less and aligned against the
mean wind indicate backbuilding and repeating cells will rotate
onshore to enhance the duration of rainfall. Where this occurs,
total rainfall through morning will likely reach 2-3". with local
amounts as much as 5" possible.

3-hr FFG from the Georgia coast northeast into the Grand Strand is
generally 2-3"/3hrs, although is locally compromised to as low as
1.5"/3hrs due to 24-hr MRMS measured rainfall of 3-5". While the
flash flood risk appears generally isolated, should any of these
training bands occur atop these more vulnerable soils, or into any
more urbanized areas, flash flooding would become more likely
overnight.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7BGhqHsZ-MdeMYOjwksyB6wdTCG6tK8QRWAaO1NuzEL4UrP7pKXRdmJBBUplSxbdGUq6= ab1_mirvjP-0jKM5Wxfv-Z0$ for graphic product...

ATTN...WFO...CHS...ILM...JAX...

ATTN...RFC...ALR...NWC...

LAT...LON 34347830 34227783 33877777 33527829 33177880=20
32887920 32188020 30948101 30848140 30988167=20
31328190 31658176 31968150 32188132 32488103=20
32868069 33318020 33877959 34207906=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 110646
FFGMPD
TXZ000-OKZ000-KSZ000-111200-

Mesoscale Precipitation Discussion 0903
NWS Weather Prediction Center College Park MD
245 AM EDT Mon Aug 11 2025

Areas affected...Southern Kansas and far Northern Oklahoma

Concerning...Heavy rainfall...Flash flooding likely

Valid 110644Z - 111200Z

Summary...An MCS moving across southern Kansas will interact with
an outflow boundary/stationary front to enhance convection through
early morning. Rainfall rates of 2-3"/hr are expected, which
through training could produce 3-4" of rain with locally more than
6" possible. Flash flooding is likely.

Discussion...The regional radar mosaic early this morning shows
expanding thunderstorms with heavy rainfall stretching across much
of southern Kansas and far northern Oklahoma. Within this
convection, dual MCVs are noted moving eastward, with a potent MCS
associated with the leading MCV pushing into central KS. This MCS
will continue to track eastward through the morning, interacting
with downstream convection, and leaving a residual outflow
boundary, to persist and intensify rainfall.

Thunderstorm activity is being driven by an impressive overlap of
synoptic and mesoscale ascent. A large-scale mid-level trough axis
is advecting eastward from the High Plains to produce broad height
falls, while an upper jet streak intensifies downstream to place
favorable RRQ diffluence atop the Central Plains. This deep layer
ascent is being enhanced by a strengthening southerly 850mb LLJ
measured via VWPs at KICT/KVNX to be 30-35 kts. This LLJ has
exhibited rapid strengthening and broadening the past few hours,
which is helping to intensify the thermodynamic environment by
drawing PWs of 1.8-2.0 inches and MUCAPE of 2000 J/kg northward to
support ongoing convection. Additionally, this LLJ is
isentropically ascending the hybrid outflow boundary/stationary
front analyzed by WPC to provide enhanced mesoscale lift.

While the CAMs are struggling to resolve the exact evolution of
the current radar, the recent HRRR and ARW have at least a better
handle on the positioning/timing of the features leading to
increased confidence in their output the next several hours. These
suggest that the LLJ will remain primarily from the south
overnight, with some local acceleration possible immediately
downstream of the MCV. As this occurs during the MCS translation
to the east, it will result in persistent and slow moving
thunderstorms downstream (Corfidi vectors collapsed to just around
5 kts) until the MCS sweeps through by morning. Additional
convective development is likely along other outflow boundaries as
well, further lengthening the duration of rainfall in some areas.
With thermodynamics supporting rainfall rates of 2-4"/hr (30-40%
chance of 3"/1hr from the WoFS, and HRRR 15-min rainfall as much
as 1"), rapid runoff is likely even despite 0-10cm soil moisture
from NASA SPoRT that is below the 20th percentile.

Most concerning, however, is the threat for training or slowing of
these intense rain rates. The HREF PMM and WoFS 90th percentile
rainfall by 12Z are quite well aligned with a maxima across
Kingman, Barber, and Harper counties, KS. Here, both these systems
predict as much as 6-7 inches of rainfall, with a broad swath of
2-5" (10-30% chance from the HREF) surrounding it and stretching
as far east as the KS/MO border. This indicates that flash
flooding is likely in many areas overnight, with an isolated
significant impact possible if these higher amounts occur over a
more vulnerable location.

Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_MmBJ-WCVuHop1IQ1whv3QTsPnmIqSts1uQ-MlIhGX88CgWhjhHzTEJH9OYuhoWTd7pS= Emu8Bqy3BEYE1pq4BZKOh5k$ for graphic product...

ATTN...WFO...AMA...DDC...ICT...OUN...SGF...TOP...TSA...

ATTN...RFC...KRF...TUA...NWC...

LAT...LON 38759928 38669773 38549705 38339627 38089551=20
37779511 37419496 36919484 36559505 36059620=20
36169750 36389914 36440071 36530111 36850170=20
37400139 38060091 38550011=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 111203
FFGMPD
MOZ000-OKZ000-KSZ000-111600-

Mesoscale Precipitation Discussion 0904
NWS Weather Prediction Center College Park MD
802 AM EDT Mon Aug 11 2025

Areas affected...Eastern Kansas into Missouri

Concerning...Heavy rainfall...Flash flooding possible

Valid 111201Z - 111600Z

Summary...Development ahead of an MCS allows a flash flood risk to
persist this morning over southeast Kansas into western Missouri.

Discussion...The MCS that crossed southern Kansas overnight has
seen renewed growth over southeast KS with a left book end vortex
turning into an MCV near Emporia. Currently activity that
developed near Chanute is now having the MCS cross which raises a
localized flash flood concern. An axis of high moisture with some
instability extending east into Missouri poses a possible flash
flood risk rest of this morning as the MCS progresses east.

SWly 850mb flow of 25-30kt is forecast by the RAP to persist ahead
of the MCS into western MO through 14Z. This will maintain PW
around 2". MUCAPE is a bit lacking ahead of the MCS generally
between 500-1000 J/kg, but given recent upward trends, there may
be sufficient instability to allow further growth. Furthermore,
areas ahead of the MCS along the KS/MO line have lowered FFG of
1.5/hr given heavy rain yesterday. Flash flooding is considered
possible over the rest of southeastern KS south of the KC metro
into western MO and this activity will continue to be monitored.

Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_j3YL7eprleIk666mpilVuZdyd0pqGJZ8v8FHZo0u1spix3hbDb1FPkO78QUsOga6I3y= sEpZEzw5x0PgwdKZa0p-VLM$ for graphic product...

ATTN...WFO...EAX...ICT...SGF...TOP...TSA...

ATTN...RFC...KRF...TUA...NWC...

LAT...LON 38869359 38179304 37429311 37069422 36949496=20
37089599 37949590 38459614 38809523=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 111239
FFGMPD
SCZ000-111600-

Mesoscale Precipitation Discussion 0905
NWS Weather Prediction Center College Park MD
838 AM EDT Mon Aug 11 2025

Areas affected...Greater Charleston SC Metro

Concerning...Heavy rainfall...Flash flooding possible

Valid 111237Z - 111600Z

Summary...Heavy thunderstorms with hourly rainfall of 2 to 3
inches should continue to lift up the SC coast this morning. At
the current pace, the heavy rates would impact Charleston near
morning high tide which would enhance localized flooding.

Discussion...A band of heavy thunderstorms is currently pushing
inland and up the coast between Hilton Head Island and Charleston.
This is being fed by 25kt Sly flow with PW still around 2.25" with
a high instability gradient with 3000 J/kg just offshore per the
RAP. Max hourly rainfall is estimated from KCLX in Charleston
County south of the Charleston metro.

As onshore flow persists this activity should persist along and
just inland from the coast with a northward trend. This would
place torrential rain over the Charleston metro near the 10a high
tide which would enhanced the localized flooding risk.
Furthermore, the 1hr FFG is generally around 2.5", so localized
flash flooding is possible over the areas impacted by this heavy
band. As of now the offshore component of the activity is somewhat
disorganized and the cloud tops have recently begun a warming
trend. However, given the high instability, redevelopment is
possible which makes for a possible flash flood risk rest of the
morning around the greater Charleston metro.



Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-KPobCGAsTzzbsZSJNwkPUZdJJifdA_l6VqbIt_Yp9tP31h81BG8dwk-VHIkWxqpye0W= IAbEwaeyDDAXc9KB5vNXivg$ for graphic product...

ATTN...WFO...CHS...

ATTN...RFC...ALR...NWC...

LAT...LON 33338015 33027946 32607964 32478033 32798053=20
32988056=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 111434
FFGMPD
FLZ000-111930-

Mesoscale Precipitation Discussion 0906
NWS Weather Prediction Center College Park MD
1033 AM EDT Mon Aug 11 2025

Areas affected...Florida Panhandle

Concerning...Heavy rainfall...Flash flooding possible

Valid 111432Z - 111930Z

Summary...Heavy thunderstorms will continue to push west from
Apalachee Bay rest of this morning. Extreme rainfall rates of 3"+
per hour should continue with this activity. Flash flooding is
considered possible through the early afternoon in this rather
flash flood resistant area.

Discussion...A trough extends up through Apalachee Bay with
rotation apparent in regional radar. Scattered thunderstorms with
torrential rain rates are focused west of this trough along the
western Apalachee Bay shoreline. Westward expansion and shifting
of this complex is expected to continue as directed by an upper
ridge extending from the Atlantic along the FL/GA border. Extreme
moisture is present along this trough axis with recent RAPs
estimating 2.5" PW. High instability is also present with SBCAPE
up to 3000 J/kg estimated by the RAP in Apalachee Bay with a tight
gradient to 1500 J/kg near the Apalachicola National Forest SW of
Tallahassee.

Continued rainfall rates of 2-3"+/hr should be expected with
potential for localized 5"+ in three hours. Given 3hr FFG around
4", the flash flood threat would be for repeating activity which
is not currently developed and recent HRRRs do not depict much
additional development through early afternoon. However, renewed
development certainly could occur given the high instability
upstream over the Bay and peak diurnal heating. This area west of
the FL Big Bend is rather flash flood resistant, but rainfall
exceeding 4" through midday would cause at least localized
flooding issues. Flash flooding is considered possible at this
time.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6CGFOW9-0_-_CLE7SbAp2XL46xR5B2AYx3xgrqwlRLUJZo_M7vTtzwxewz_eguWWm7lm= U_pHUghRRE5QzpTpagfb4v8$ for graphic product...

ATTN...WFO...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 30398483 30138428 30008414 29748430 29568470=20
29508501 29648544 30158588 30378546=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 111624
FFGMPD
NCZ000-SCZ000-112215-

Mesoscale Precipitation Discussion 0907
NWS Weather Prediction Center College Park MD
1224 PM EDT Mon Aug 11 2025

Areas affected...Carolinas

Concerning...Heavy rainfall...Flash flooding possible

Valid 111622Z - 112215Z

Summary...Heavy showers and isolated thunderstorms will continue
developing along an axis from the South Carolina Coast to the
North Carolina Blue Ridge rest of this afternoon. Rainfall of
2"/hr is likely to continue and expand in coverage with localized
totals exceeding 4" possible rest of this afternoon. Localized
flash flooding can be expected.

Discussion...Broad scale southerly flow is present over the
Southeast with a trough along the Carolina Coast. A somewhat
focused corridor of activity has developed from the SC coast north
of Charleston inland to the NC Blue Ridge which is ahead of a
mid-level vort lobe drifting north over southern SC per recent RAP
runs. Heavy thunderstorms moved through Charleston late morning
with continued development lifting along the coast. A new cluster
of thunderstorms have developed in the past hour over interior
northern SC and heavy showers continue from this morning from
around Charlotte west through the southern NC Blue Ridge (with
further growth possible through the diurnal max). Robust,
tropically sourced moisture is present over this corridor with
2.3" PW along the coast and 2" butting up against the Blue Ridge
which is around 2 sigma above normal across the region. SBCAPE of
1500-2500 J/kg along this corridor is allowing this development
and warm rain processes are maximizing rates with with recent
hourly rainfall of 1.5-2" in the heaviest activity.

Recent HRRR runs are a little subdued compared to reality, but
generally focus afternoon development along this corridor. Flash
flood guidance is 1.5-2"/hr in the Piedmont/foothills and
generally 2.5"/hr in the Coastal Plains. The combination of
extreme moisture and sufficient instability should allow for
localized extreme rainfall rates of up to 3"/hr which would cause
localized flash flooding rest of the afternoon.

Given the broad scale of the elevated moisture across the
Southeast, further consideration will be given to other areas
outside this corridor (which is purposefully just north of
vulnerable Columbia based on trends), but for now this appears to
be the most likely area for flash flood concern this afternoon.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!77LrHy1BKj_4tDjjzsU5WhBxJE4Ckbp5p4kZZxM9J6FPdb3bTyIOg5lbRxyhTcjy5DZU= QMAAciAty_IQwNIQGgOoLvg$ for graphic product...

ATTN...WFO...CAE...CHS...GSP...ILM...RAH...RNK...

ATTN...RFC...ALR...NWC...

LAT...LON 36148091 35548025 34977938 34157846 33837816=20
33377879 32557976 33398034 34238083 34838193=20
35248224 35698214 36108153=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 111827
FFGMPD
VAZ000-NCZ000-112330-

Mesoscale Precipitation Discussion 0908
NWS Weather Prediction Center College Park MD
227 PM EDT Mon Aug 11 2025

Areas affected...Northeast North Carolina through Hampton Roads

Concerning...Heavy rainfall...Flash flooding possible

Valid 111825Z - 112330Z

Summary...Heavy thunderstorms will continue developing and
drifting north from northeast North Carolina through Hampton Roads
this afternoon. Localized rainfall of 2.5"/hr is likely to
continue with possible totals of 4" possible. Localized flash
flooding can be expected to 23Z.

Discussion...Southerly flow over eastern NC is pushing 2" PW up
over Hampton Roads. Scattered thunderstorms have developed over
northeast NC with newer activity in southern sections of Virginia
Beach. Sufficient instability is present with SBCAPE of 1500-2500
J/kg with a decreasing gradient north of Hampton Roads and warm
rain processes are maximizing rates with with recent hourly
rainfall of 2.5" in the heaviest activity.

Recent HRRR runs are decent in coverage, but somewhat light on
intensity and depict a bit of a northward drift in activity over
southeast VA rest of the afternoon. Flash flood guidance is
higher, generally 2.5"/hr, but lower as typical for the Hampton
Roads metro around 1.5"/hr. The combination of high moisture and
sufficient instability should allow for localized rainfall rates
of up to 3"/hr which would cause localized flash flooding rest of
the afternoon, especially in urban areas.


Jackson

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!84iEyxG36aIxsn_UaI8WR-zFv1D7DKjdtU4DWRFyckzMD1qb9skYB65hWAW1HNEXfdDN= -GIoES9MMpQwsa6LcprM4fo$ for graphic product...

ATTN...WFO...AKQ...MHX...RAH...

ATTN...RFC...ALR...RHA...NWC...

LAT...LON 37217644 37007597 36567569 36077553 35727554=20
35537676 36417780 36877783 37137736=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 111904
FFGMPD
VAZ000-NCZ000-112333-

Mesoscale Precipitation Discussion 0909
NWS Weather Prediction Center College Park MD
303 PM EDT Mon Aug 11 2025

Areas affected...portions of central NC

Concerning...Heavy rainfall...Flash flooding possible

Valid 111903Z - 112333Z

Summary...Pulse convection with heavy rain is moving towards a
more hydrologically sensitive area over the next few hours.=20
Hourly amounts to 3" with local totals to 5" are possible, which
could lead to isolated to widely scattered flash flood concerns.

Discussion...Thunderstorms across NC are moving inland near and
ahead of a surface trough/convergence zone. Despite its forward
progression, hourly amounts to 3" -- if not higher -- have been
seen with this activity per WSR-88D radar estimates. While
activity is generally moving northward, some cells are showing
more chaotic motion, leading to occasional mergers which is aiding precipitation efficiency. Precipitable water values are 2-2.25"
per GPS data. ML CAPE of 1500-2000 J/kg exists in the region.=20
Effective bulk shear is shy of 25 kts, leading to its pulse
character.

Of concern is a swath of the Piedmont which has received 300-600%
of their average weekly rainfall from Asheville northeast through
Durham to just across the VA border. This wet week should have
made the soils more sensitive, and shows up as a lower area of
flash flood guidance values. Isolated to widely scattered flash
flood concerns should be mostly within this wet area of the
Piedmont or in urban areas.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-VKPMZClq23jekxG9GBgFYK-HQXrIez8PzfDMiyvSQE9EIEPI12bJdMFzIG0ZhJOno55= xsocLobH1wAdb1EB4XJMsnw$ for graphic product...

ATTN...WFO...AKQ...GSP...ILM...MHX...RAH...RNK...

ATTN...RFC...ALR...RHA...NWC...

LAT...LON 37167743 36617798 36107755 35667712 35567698=20
35017741 34627867 35417994 36268095 36918014=20
37107883=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 111947
FFGMPD
TXZ000-OKZ000-COZ000-NMZ000-120146-

Mesoscale Precipitation Discussion 0910
NWS Weather Prediction Center College Park MD
347 PM EDT Mon Aug 11 2025

Areas affected...circa northeast NM & the TX Panhandle

Concerning...Heavy rainfall...Flash flooding possible

Valid 111946Z - 120146Z

Summary...Cumuli are showing growth near the NM/CO border and
across portions of the TX Panhandle. Showers and thunderstorms
which evolve from them have the potential for hourly rain amounts
to 2" with local totals to 4".

Discussion...Cumuli are getting feisty near the NM/CO border in
area terrain not far to the east of an upper level low dropping
into northwest NM, with some signal of cumulus growth also
apparent in the northwest TX Panhandle where a surface convergence
zone/weak baroclinic trough was noted in 19z surface observations.
Precipitable water values of 0.5-1.5" lie across the region. An
ML CAPE gradient is noted near the convergence zone on SPC
mesoanalyses, with 500-2000 J/kg values in its vicinity.=20
Effective bulk shear of 20-30 kts exists at the moment. CIN is
reducing across the region.

While there's some disparity amongst the mesoscale guidance, the
most coherent signal shows that convection near the CO/NM border
forms and drops southeast to south-southeast, roughly in line with
the ML CAPE gradient and 850-400 hPa mean wind but somewhat into
the instability field. Some of the activity that forms across
portions of northern and central NM then turns east along the trough/instability gradient into the TX Panhandle while growing in
scale as the low-level inflow from the Gulf begins to increase and
moisture import increases further. Given the available
parameters, hourly rain to 2" with local totals to 4" are
possible. The region has been dry over the past week, so any
flash flood issues are most likely to be isolated to widely
scattered and near area burn scars, dry washes/arroyos, or across
urban areas within this region.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6MVkTYOPbBiYoy0dlZKlJ0tTeBEDfkLTRi6TA19pauTbPQs3qA7fFm-iaZQ_g0jRffI5= 21zuMLyiCZPHemO7Ev7vb1g$ for graphic product...

ATTN...WFO...ABQ...AMA...LUB...OUN...PUB...

ATTN...RFC...FWR...TUA...NWC...

LAT...LON 37660514 37450462 36290277 36660047 36529988=20
35769998 34490079 33810262 33750455 34780620=20
36000569 36500540 37230523=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 112018
FFGMPD
MOZ000-ARZ000-OKZ000-KSZ000-120147-

Mesoscale Precipitation Discussion 0911
NWS Weather Prediction Center College Park MD
417 PM EDT Mon Aug 11 2025

Areas affected...KS/MO/OK border southwest across central OK

Concerning...Heavy rainfall...Flash flooding possible

Valid 112017Z - 120147Z

Summary...Showers and thunderstorms have begun to develop from=20
southwest MO into central OK. Hourly rain amounts to 2.5" with
local totals to 4" are possible, which could lead to isolated to
widely scattered flash flood concerns.

Discussion...A surface convergence zone/baroclinic trough
stretches from western MO past the MO/KS/OK border junction
through north-central OK. Near this boundary is an ML CAPE
gradient, with values of 2500-3000 J/kg lying to its south. An
MCV from overnight convective activity is entering central OK from
the west while another overnight MCV moves across portions of IA
to the north. Precipitable water values are ~1.8". Effective
bulk shear is just shy of 25 kts per SPC mesoanalyses. CIN has
nearly eroded.

The mesoscale guidance appears to be modeling the development of
this convective activity well, thus far. It is showing the entire
axis lighting up over the next several hours, which will help
force the boundary southward late in the period. Northeastern
areas near the KS/MO border have had a bit of rain lately, leaving
them more sensitive. Otherwise, it's been dry across much of OK.=20
Issues should primarily reside where soils have been partially
compromised in northeastern areas, in urban areas, and any
sections of the Ozarks or Boston Mountains that thunderstorms with
heavy rainfall transect.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6JcSoLpPMAoIG3mXlrrw1ivQ9BbBREYoZEsirevNHU6ma63ijgnteiqi8nDHQiYPjB-1= 5CmcqpYM5NdycaZwmFt_94w$ for graphic product...

ATTN...WFO...EAX...ICT...OUN...SGF...TSA...

ATTN...RFC...KRF...ORN...TUA...NWC...

LAT...LON 38169409 37899353 37259353 36639383 35409532=20
35099798 35889815 36849682 37509557 38149468=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 120045
FFGMPD
MOZ000-ARZ000-TXZ000-OKZ000-NMZ000-120643-

Mesoscale Precipitation Discussion 0912
NWS Weather Prediction Center College Park MD
844 PM EDT Mon Aug 11 2025

Areas affected...portions of Eastern NM, the TX Panhandle, & OK

Concerning...Heavy rainfall...Flash flooding likely

Valid 120043Z - 120643Z

Summary...Showers and thunderstorms across this region are
expected to concentrate near southwest OK by 07z. Hourly amounts
to 3" with local totals to 5" are expected, which would continue
to lead to scattered flash flood concerns.

Discussion...Thunderstorms continue to build and move across
portions of eastern NM, the TX Panhandle, northwest TX, and
portions of OK, focusing and being driven forward by outflow
boundaries. They have a history of producing hourly amounts to 3"
with local totals to 5" thus far this afternoon and evening. A ML
CAPE gradient exists near the effective frontal zone, with pockets
of 2000-3000 J/kg of instability in its warm sector. Effective
bulk shear has spread eastward, with a magnitude of 25-35 kts
regionally. Precipitable water values are 1-1.25" in the High
Plains and 2"+ across portions of OK. So far, much of the
thunderstorm activity has resembled pulse convection, with cell
mergers and very short periods of training occurring and being
important to heavy rain efficiency. In some areas, backbuilding
has been noted. Central and southern OK convection has been
backbuilding and pushing slowly westward, driven by outflow
boundaries.=20

Both the 12z REFS and 18z HREF probabilities suggest a set of
outflow boundaries approaching Clovis NM helps drive a new
convective cluster which joins forces with TX Panhandle activity
in their combined quest to move eastward along an outflow boundary intersection. This cluster has the benefit of a stronger
low-level inflow from the Gulf. Meanwhile, outflow boundaries in
OK pushes convective clusters apart in central OK early on,
driving some activity eastward to form one last merger not far
from McAlester OK. Another, more significant merger between the
TX Panhandle/northwest TX activity and the OK activity is
advertised across far southwest OK by 07z with the TX activity
appearing to grow in dominance/importance as it attempts to
continue eastward thereafter, possibly aided to a growing cold
pool. While there have been small pockets of heavy rainfall, much
of the region has been dry during the past seven days. Scattered
flash flood issues are expected to be mainly urban.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9aQARXSXRcfoWpzQbtTM7luyrGvNLApaUgxR8KwV5wRMFwP1DSY9Ui4XdT3JTmaavS0h= V0v3ZFu2_7UFnMKuHxWNg2Q$ for graphic product...

ATTN...WFO...ABQ...AMA...FWD...LUB...MAF...OUN...SGF...SJT...
TSA...

ATTN...RFC...FWR...TUA...NWC...

LAT...LON 36579481 36509413 35299454 34019570 33399700=20
33269908 33740111 33350320 33420399 33580428=20
33710506 34270438 35090434 35250306 35500190=20
35790088 35599967 35459910 35379869 35349741=20
35779619 36559495=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 120113
FFGMPD
INZ000-ILZ000-120541-

Mesoscale Precipitation Discussion 0913
NWS Weather Prediction Center College Park MD
912 PM EDT Mon Aug 11 2025

Areas affected...northeast IL

Concerning...Heavy rainfall...Flash flooding possible

Valid 120111Z - 120541Z

Summary...Showers and thunderstorms have begun to develop in
north-central IL, trying to attain a training signature as they
aim towards Chicagoland and grow in coverage. Hourly rain amounts
to 2.5" with local totals to 4" are possible, which would be
problematic in urban areas.

Discussion...since 2330z, showers and thunderstorms have been
developing, slowly growing in scale, and trying to align south and
east of Peru IL within an area of low-level convergence. Hourly
rain amounts in spots have exceeded 1.5" per radar estimates.=20
Precipitable water values are ~1.9 per GPS data. ML CAPE is
2500-3500 J/kg to their south. Effective bulk shear of 25-30 kts
is trying to align the activity.

The 12z & 18z HREF runs were insistent on this activity forming,
whereas the 06z and 12z REFS had a much weaker signal, so used the
HREF as a guide (outside of the IA contribution which is
underperforming on the HREF). The convective packet is moving
east-northeast at 15-20 kts, with individual cells moving quicker
than the packet as a whole. Hourly rain amounts to 2.5" with
local totals to 4" are possible over the next 3-4 hours. This
could lead to problems in Chicagoland tonight.

Roth

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8D0Dkr8qJgiiOsyFHMaTOAUmevGRDrB_k1_YukUqwjPYMd4mKpJvJOsTsDOnIOQO_dxT= KHM2l4AHhS_brtmO0U5dzfo$ for graphic product...

ATTN...WFO...DVN...ILX...LOT...

ATTN...RFC...MSR...NWC...

LAT...LON 42208780 41668747 40738957 40698991 40858984=20
41598892=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 120331
FFGMPD
ILZ000-MOZ000-IAZ000-120900-

Mesoscale Precipitation Discussion 0914
NWS Weather Prediction Center College Park MD
1130 PM EDT Mon Aug 11 2025

Areas affected...Northeast Missouri, Southeast Iowa, Western
Illinois

Concerning...Heavy rainfall...Flash flooding possible

Valid 120329Z - 120900Z

Summary...Showers and thunderstorms expanding across northern
Missouri will lift slowly northeast overnight. Rainfall rates
within this convection will reach 1-2"/hr, locally higher at
times, resulting in 1-2" of rainfall. This may cause flash
flooding.

Discussion...The regional radar mosaic tonight shows an expanding
area of showers and thunderstorms developing from north-central
Missouri into southeast Iowa. This convection is blossoming in
response to ascent driven by an overlap of modest height falls
downstream of a shortwave trough axis positioned over Nebraska,
and an MCV from remnant convection moving into southern Iowa.
Downstream of these features, a S/SW LLJ at 850mb has been
recently measured via local VWPs to be 15 kts, which is
originating from a region of elevated thermodynamics sufficient to
fuel heavy rain in thunderstorms. As this LLJ locally backs and
accelerates downstream of the MCV, it will draw PWs as high as 2
inches, and MUCAPE above 2000 J/kg, northward, providing
additional fuel for persistent convection within a WAA regime
overnight.

Rainfall rates as estimated via local radars have been generally
modest so far at around 0.5-1"/hr. However, as the LLJ continues
to strengthen it will not only resupply the more favorable
thermodynamics northward, but also result in enhanced convergent
ascent to drive stronger convection. During the next few hours,
the CAMs, while mostly under-representing the current activity,
suggest thunderstorms will become more widespread, and the HREF
neighborhood probabilities indicate a 10-20% chance of 2"/hr rain
rates developing, with brief rates to 3"/hr possible as shown by
the 15-min HRRR rain accumulation. At the same time, while 0-6km
mean winds will remain progressive to the northeast at 20-25 kts,
sufficient bulk shear of 20-25 kts will help organize storms into
clusters, coincident with Corfidi vectors collapsing to 5 kts or
less and veering to the south. This indicates an increasing threat
for backbuilding/training convection within the improving WAA.

Although HREF 6-hr rainfall probabilities for 3" are modest at
10-15%, indicating that generally 1-2" of rain is likely with
locally higher amounts, this may still be sufficient to cause
rapid runoff. Not only will the rates be intense, but FFG is as
low as 1.5-2"/3hrs for which the HREF exceedance probabilities
peak around 20%. This is further evidence for the increasing flash
flood risk overnight, with at least isolated instances possible in
urban areas, over the more vulnerable soils, or where the most
significant training can occur.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6-Wg4J8PPfQV0EfImKwv_a2YKq5N6tCvRJ74PlVn6hiQp2b993WAitry3AS8TcYfvmL-= UtafYSWDJjsPlnjvfC8K56w$ for graphic product...

ATTN...WFO...DMX...DVN...EAX...ILX...LSX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 42079071 41298973 40588957 39738995 39249075=20
39199086 38789174 38629258 38949335 39559371=20
40229386 40909354 41699259=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 120423
FFGMPD
MOZ000-ARZ000-TXZ000-OKZ000-121000-

Mesoscale Precipitation Discussion 0915
NWS Weather Prediction Center College Park MD
1222 AM EDT Tue Aug 12 2025

Areas affected...Eastern Oklahoma, Western Arkansas, far Northeast
Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 120421Z - 121000Z

Summary...Slow moving showers and thunderstorms will continue to
pulse up along outflow boundaries and storm mergers overnight.
Rainfall rates of 2-3"/hr are expected, which could produce 1-2"
of rain in 30 minutes. Flash flooding is possible.

Discussion...The regional radar mosaic tonight shows an expansion
of convection across eastern Oklahoma into western Arkansas. This
convection is associated with multiple remnant outflow boundaries
that are clearly evident on radar, with convergence along these
boundaries leading to rapid updraft intensification to produce
dditional convective development. Estimated rainfall rates have
been as high as 2"/hr from KSRX, supported by rich thermodynamics
characterized by GPS measured PWs of 1.7 inches overlapping MUCAPE
of 1000-2000 J/kg. Additional ascent is being provided via slow
height falls downstream of a mid-level trough axis centered across
KS/OK.

The high-res CAMs are really struggling tonight with the current
activity, so their solutions must be used cautiously. However, an
ingredients based approach to the evolution combined with analysis
of current radar trends suggests that there can be several more
hours of slow moving storms before instability gets exhausted or
overturned. With PWs and MUCAPE remaining robust within the
pre-convective environment, any mergers/outflow collisions should
additionally result in thunderstorm growth, and a slow trend E/SE
in coverage is likely. 0-6km bulk shear across the region is
minimal at less than 20 kts, so storms should remain primarily of
the pulse variety. This suggests limited temporal duration of any
individual cell, but with chaotic motions driven primarily by
these small scale collisions thanks to weak 0-6km mean winds, some
places could receive multiple rounds of convection.

These thunderstorms will likely continue to produce rainfall rates
of 2-3"/hr (HREF probabilities for 2"/hr 15-30%), so even though
residence times will be limited, any storm may produce a quick
1-2" of rain in well under an hour. This will be sufficient to
cause rapid runoff despite elevated FFG, and a few instances of
flash flooding are possible overnight, especially across any more
sensitive or urban areas.

Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-s5q1JYBL5Es53Nme6TuhNiAPPNOU4PEWEWjW23lwSk5tBH8v8aZ9_SFS7_0m6LPLipU= 9KTQQ1-3tQOnpMSJUz4lh2g$ for graphic product...

ATTN...WFO...FWD...LZK...OUN...SGF...SHV...TSA...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON 37169302 36809253 35989236 34889240 34079276=20
33419371 33009481 32799566 32759667 33079736=20
33579774 34119777 34389725 34659630 35069559=20
35709530 36779400=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 120647
FFGMPD
TXZ000-OKZ000-121200-

Mesoscale Precipitation Discussion 0916
NWS Weather Prediction Center College Park MD
247 AM EDT Tue Aug 12 2025

Areas affected...West/Central Oklahoma into far Northern Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 120646Z - 121200Z

Summary...Slow moving showers and thunderstorms will move across
parts of Oklahoma and Texas through morning. Rainfall rates of
2-3"/hr are likely, which through this slow motion could produce
2-4" of rainfall and instances of flash flooding.

Discussion...The GOES-E IR imagery early this morning indicates a
new swath of cooling cloud tops north of a large convective
complex moving from the Texas Panhandle to along the Red River
Valley of the South. This fresh convection is associated with
increasing convergence along the nose of a S/SE oriented, but
modest, 10-15kt 850mb LLJ measured via regional VWPs and analyzed
by the SPC RAP. Despite the modest intensity, this LLJ is
favorably transporting robust thermodynamics northward to support
this new convection, with PWs above 1.75 inches and MUCAPE
exceeding 1000 J/kg. Into these thermodynamics, forcing for ascent
is being provided via convergence along the aforementioned nose of
this LLJ, but also synoptically downstream of a trough axis
kicking slowly eastward from the High Plains, and an embedded
shortwave moving into the region through the base of the trough.
Additionally, a small but well placed 300mb jet streak over KS is
leaving favorable RRQ diffluence to increase deep layer lift.

The CAMs are generally struggling with the current increase of
convective coverage, so confidence in evolution through morning is
somewhat limited. However, there is some evidence in the recent
NAM3Km and RRFS of handling this new convection a bit better, so
these are used to help gauge the flash flood risk. As the LLJ
gradually veers (but with some acceleration immediately downstream
of the shortwave) it should continue to resupply favorable
thermodynamics to support thunderstorms with heavy rainfall. At
the same time, forcing for ascent will persist for several more
hours before the LLJ veers too far to the west by morning,
suggesting thunderstorms will continue to expand. Rainfall rates
within this development should exceed 2"/hr at times as reflected
by both HREF and REFS neighborhood probabilities, and with mean
0-6km winds of just 5-10 kts aligned with propagation vectors
along the nose of this LLJ, regenerating and training cells with
these intense rain rates are likely.

Where the most pronounced training occurs, this could result in
2-4" of rainfall as reflected by the HREF/REFS PMM. While there is
considerable uncertainty into the placement of this heaviest
rainfall due to the lack of model agreement and some interruption
of the flow possible from other convective clusters in the
vicinity, the EAS probabilities indicate the best threat will be
along and just south of this LLJ nose. Regardless of the exact
placement, slow moving/backbuilding of these intense rain rates
will pose a flash flood risk during the next few hours.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-zBZKlRcWbXq2Q11z1MiHkmTXWqytgupKL_nDayQEDtE3iHItqR-6Xvncg_gWfN5ykiC= LY1VQaGXJEOrJgHBBWDIDJc$ for graphic product...

ATTN...WFO...AMA...FWD...LUB...OUN...SJT...

ATTN...RFC...FWR...TUA...NWC...

LAT...LON 36629994 36309878 35869772 35169699 34549686=20
34049707 33569747 33259812 33199891 33569973=20
33990014 34780031 35420050 36020077 36500118=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 120958
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-121430-

Mesoscale Precipitation Discussion 0917
NWS Weather Prediction Center College Park MD
558 AM EDT Tue Aug 12 2025

Areas affected...Central Gulf Coast through central Alabama

Concerning...Heavy rainfall...Flash flooding possible

Valid 120957Z - 121430Z

Summary...Showers and thunderstorms streaming onshore will train
north this morning. Rainfall rates of 2-3"/hr are likely, which
could produce 2-4" of rain along the immediate coast. This may
cause flash flooding.

Discussion...The regional radar mosaic early this morning shows an
expansion of showers with isolated thunderstorms across the
northern Gulf. Although instability continues to be modest onshore
(MUCAPE 500-1000 J/kg inland from the coast) a sharp instability
gradient exists across the FL Panhandle westward to the coasts of
AL and MS. Recent analysis of 850mb winds from the regional VWPs
and the SPC RAP analysis indicate the inflow has increased to
20-30 kts with some local backing to the SE, leading to increasing
N-S oriented convergence which is helping to drive lines of
convection pushing onshore. At the same time, weak MCVs noted in
reflectivity and a surface trough analyzed by WPC are helping to
enhance ascent locally as well.

Ascent into the area will remain impressive through morning, and
may actually intensify as the 850mb LLJ reaches 1.5x the mean wind
(850mb winds to 30 kts, mean wind to 20 kts) forcing more broad
lift. This ascent will act upon thermodynamics that will become
increasingly robust through extreme PWs measured by GPS above 2.3
inches and MUCAPE which will gradually expand inland both through
the 850mb transport but also in response to daytime heating.
Together, this suggests that convection will continue push
onshore, while gradually spreading northward in response to the
strengthening instability.

The high-res CAMs have struggled this morning to resolve the
ongoing activity, which is more widespread and intense than any
available guidance. However, the recent HRRR runs have started to
catch on and insist that convection will become widespread later
this morning. This appears likely, and as the environment becomes
more thermodynamically rich, rainfall rates will likely reach
2-3"/hr as progged by both HREF neighborhood probabilities and the
HRRR 15-min rainfall accumulation. More concerning to the flash
flood risk will be that storms will likely train repeatedly south
to north as mean 0-6km winds of 10-15 kts suggest progressive
cells, but propagation vectors aligned anti-parallel and into the
Gulf indicate backbuilding potential. Where this training is most
prolonged, 2-4" of rainfall is possible through the morning.

FFG across this area is quite high at 3-4"/3hrs, and HREF FFG
exceedance probabilities are generally below 15%. However, where
any of these narrow training bands persist, especially if they
occur over urban areas, instances of flash flooding may result,
with the greatest potential occurring along the immediate coast.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9mGE-pFkZny07w97O8ihRpXeXudfjyAWcejdl_7aYyLFwRq-vDMdHTt969QEt-t5BnRH= GQLDve1h_KI3zL_cashyD_0$ for graphic product...

ATTN...WFO...BMX...HUN...JAN...LIX...MEG...MOB...TAE...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 34128738 33708648 33128592 31628530 30388504=20
30028536 30118611 30178665 30218707 30088793=20
29498858 29138887 28928913 28978948 29128970=20
29118999 29259022 29589018 29918978 30208937=20
30458887 30738836 31338817 32178815 33098835=20
33918831=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 121209
FFGMPD
NCZ000-SCZ000-GAZ000-121808-

Mesoscale Precipitation Discussion 0918
NWS Weather Prediction Center College Park MD
808 AM EDT Tue Aug 12 2025

Areas affected...portions of central/Upstate South Carolina and
central North Carolina

Concerning...Heavy rainfall...Flash flooding possible

Valid 121208Z - 121808Z

Summary...Areas of heavier rainfall are materializing across the
discussion area and 1 inch/hr rain rates are increasing in
coverage. These rates are falling on sensitive ground conditions
from prior rainfall. Flash flooding is possible this morning.

Discussion...Over the past half hour, radar and satellite have
indicated an uptick in convective intensity and coverage generally
in areas from central South Carolina into southwestern North
Carolina. This uptick in convective coverage appears to be tied
to a weak mid-level shortwave trough/vorticity max over central
South Carolina. The showers/storms are in a marginally unstable,
but very moist environment (1.5-2 inch PW values, 1000 J/kg
SBCAPE) with weak inhibition, fostering efficient rainfall rates
with the ongoing activity. Latest MRMS data suggests that 1
inch/hr rain rates were beginning to materialize in a few spots.=20 Furthermore, these rates were falling on sensitive local ground
conditions due to prior rainfall, with FFG thresholds below 0.25
inch/hr in a few spots across the discussion area.

Models/observations are all suggestive of a gradual increase in
both coverage and intensity of convection through the morning
hours. With weak southwesterly steering flow in place, several
areas of slow-moving convection and occasional cell mergers are
expected to develop and boost rain rates into and above the 1
inch/hr threshold at times. These rates will pose a flash flood
risk, though the greatest risk of impacts may occur near sensitive
urban areas and locales that have experienced the highest rainfall
totals over the past 1-2 days. Areas just west of Columbia, SC
could experience excessive runoff in the near term, with
additional locales (including urban areas near Raleigh/Durham and
Columbia) experiencing an increasing threat through 16Z/noon EDT
or so.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4EKeuxKsk7-uujb1RTjzVj24QTN_HxsiRRw3en8OGRvX76ScVdRYaokfSDnyrYKlMvi9= Lvb1fb0043lWWUYt3lj3bWE$ for graphic product...

ATTN...WFO...CAE...GSP...ILM...MHX...RAH...RNK...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 36297879 35577734 33738053 33548204 35158286=20
35978159 36268043=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 122115
FFGMPD
MIZ000-INZ000-ILZ000-130200-

Mesoscale Precipitation Discussion 0919
NWS Weather Prediction Center College Park MD
514 PM EDT Tue Aug 12 2025

Areas affected...Greater Chicagoland and surrounding portions of
IL/OH/MI

Concerning...Heavy rainfall...Flash flooding possible

Valid 122110Z - 130200Z

Summary...Hourly rainfall totals of 1-2" may locally train/repeat
over sensitive urban areas. Locally significant/life threatening
instances of flash flooding are possible.

Discussion...Convection has proliferated in the vicinity of a
surface trough of low pressure this afternoon, extending from
western MI through northern IL. While deep layer moisture flux
convergence has spiked synoptically along the trough axis, an
enhanced meso to microscale area of near surface convergence
exists along the southern shore of Lake Michigan (and most
pronounced along the IL shore). This is occurring as upper-level shear/divergence is only increasing, as the base of a potent
shortwave trough progresses eastward across northern MN/WI. The
idealized right-entrance region of an associated jet streak (~110
kts at 250 mb) may allow for this convection to persist for longer
than anticipated, as CAMs have generally been much slower/weaker
with convection than actual observational trends. With the
mechanism for lift and convective longevity clearly established,
plentiful instability (3000-3500 J/kg across northern IL) and
anomalous tropopsheric moisture (~2.0" PWs above the 90th
percentile, per ILX sounding climatology). MRMS estimates hourly
rainfall amounts locally as high as 2", and even without
training/repeating (thus far) the associated CREST unit streamflow
values suggests minor to moderate flood impacts are already
occurring (particularly where these 2" totals are co-located with
more sensitive urbanized terrain).

Going forward, CAMs suggest the potential for additional localized
totals of 2-4" (HREF 40-km neighborhood exceedance probs for 3"
threshold of 10-20% through 03z). Since most models were too slow
to develop convection, much of this forecast rainfall may have
simply occurred early. However, given the aforementioned favorable
mesoscale environment (with little depletion of instability and
increasingly favorable dynamics) it's quite possible that heavy
rainfall will continue for several hours still, eventually coming
to an end between 00-02z. Given the potential for
training/repeating with little movement in the trough axis and
baroclinic lake enhancement, a significant instance or two of
flash flooding is possible (and may become life threatening in
more sensitive, low-lying populated areas of Chicagoland).

Churchill

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-sAtEx_qMfvLfJ_Y_lQ-4btitGjJQjzNIHeugNXXgqFX5JYKzEWsIMiAeImX8FqLvam0= WiqkdDOBwKZk8uI-9NtV97I$ for graphic product...

ATTN...WFO...ILX...IWX...LOT...

ATTN...RFC...MSR...TIR...NWC...

LAT...LON 42468708 42228647 41838622 41178670 40648751=20
40468857 40608902 41598821 42218789=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 130649
FFGMPD
FLZ000-ALZ000-MSZ000-131200-

Mesoscale Precipitation Discussion 0920
NWS Weather Prediction Center College Park MD
248 AM EDT Wed Aug 13 2025

Areas affected...Portions of the Central Gulf Coast

Concerning...Heavy rainfall...Flash flooding possible

Valid 130647Z - 131200Z

Summary...Showers and isolated thunderstorms will train onshore
through morning from eastern MS through the western FL Panhandle.
Rainfall rates within these tropical downpours will reach 3"/hr at
times, which through training could produce stripes of 2-4" of
rain. Flash flooding is possible.

Discussion...The regional radar mosaic early this morning shows a
rapid expansion of tropical showers with isolated thunderstorms
aligned south to north in the vicinity of Mobile Bay, AL. This
expanding convection is associated with a weak surface trough
extending across the area, with upstream onshore flow from the
Gulf drawing impressive moisture northward. The greatest
instability (MUCAPE above 1000 J/kg) is confined to the immediate
coast, and this has been the demarcation of the heaviest rainfall
rates so far this morning, but PWs above 2 inches extend all the
way into northern AL, with recent GPS measured PWs reaching 2.4
inches near Mobile Bay. These extreme PWs and warm cloud depths
over 15,000 ft have been supporting efficient warm-rain collision
processes, with MRMS 15-min rainfall measured as high as 0.7
inches (3"/hr) already in some of the cells training onshore.

The high-res CAMs are actually in pretty good agreement both with
the footprint and amount of the expected rainfall through around
12Z, focusing from the AL/MS border eastward towards the Emerald
Coast of the Florida Panhandle. Here, 850mb winds measured via
current VWPs have already reached 15-25 kts, exceeding the mean
wind of 10-15 kts to drive enhanced ascent through convergence. As
this inflow continues to draw robust thermodynamics northward,
regenerating cells are expected to develop across the Gulf and
then repeatedly train northward and onshore.

The HREF neighborhood rainfall rate probabilities for 2"/hr peak
above 60% during the next few hours, suggesting the deeper cores
will contain rates that may exceed 3"/hr at times. Although storms
will move steadily northward, with several rounds of rainfall
anticipated, this could result in 2-4" of rain with locally higher
amounts possible as reflected by HREF/REFS 5"/6hr probabilities
reaching 15-40%. The heaviest rainfall is expected to be along the
immediate coast in the vicinity of Mobile Bay, but as the axis of
elevated 850mb winds push northeast through morning, the
environment could support more expansive heavy rainfall farther
north into parts of southern AL as well. This suggests that while
any impacts will be most likely along the immediate coast and over
urban areas, any training of these intense rates, especially as
instability pushes northward later this morning, could result in
instances of flash flooding.

Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-L8Z3naUd_aU_PnOhf_tjoUlmUbMikEjE__X7VOIyUgudZcI23OlZBoO6tphKcpJ5aE9= 7vmbHKW50YIu6jCatQXU5Zo$ for graphic product...

ATTN...WFO...BMX...LIX...MOB...TAE...

ATTN...RFC...ALR...ORN...NWC...

LAT...LON 32218747 32128689 31788655 31188610 30758593=20
30308583 30118653 30068714 29998814 30068854=20
30148882 30858909 31258859 31628832 32008791=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 130842
FFGMPD
TNZ000-KYZ000-ALZ000-MSZ000-MOZ000-ARZ000-131330-

Mesoscale Precipitation Discussion 0921
NWS Weather Prediction Center College Park MD
442 AM EDT Wed Aug 13 2025

Areas affected...Northeast Arkansas through Central Tennessee

Concerning...Heavy rainfall...Flash flooding possible

Valid 130841Z - 131330Z

Summary...Showers and thunderstorms will drift across the region
through morning. Intense rainfall rates of 2-4"/hr will likely
cause pockets of 2-3" of rainfall in less than 1 hour. This may
cause instances of flash flooding, especially in urban areas.

Discussion...Showers and thunderstorms noted on the regional radar
mosaic early this morning have rapidly expanded across western and
central Tennessee and back into northeast Arkansas. This
convection is blossoming within a plume of elevated moisture
evident on the GOES-E WV imagery on SW flow emerging from the Gulf
Coast downstream of a mid-level trough axis that is still hung
back across MO/AR. Cloud top cooling is continuing to occur across
the area as well, indicating that convection is going to continue
to develop and intensify in response to deep layer ascent provided
through modest height falls, weak upper jet diffluence, and
low-level convergence along a surface trough. Together these are
driving sufficient lift for the rapid uptick in thunderstorm
coverage, as this ascent is working upon robust thermodynamics
characterized by PWs measured by GPS of more than 2 inches
coincident with a ribbon of 1000-2000 J/kg MUCAPE.

Storms that have developed already have produced MRMS measured
1-hr rainfall of more than 2 inches in some areas, and the
resulting FLASH unit streamflow response has reached 200-400
cfs/smi. This has prompted already at least one FFW SW of
Nashville, TN. The concern through the morning will be that these
storms will continue to produce excessive rainfall rates of
2-4"/hr, although the HREF and REFS neighborhood probabilities for
2"/1hr are modest at just 10-15%. However, the CAMs are really
struggling with the ongoing activity, so the ensemble
probabilities are suffering and are likely too low. Additionally,
with the primary 850mb inflow from the W/SW, propagation vectors
have dropped to 5 kts or less and are aligned with the weak mean
0-6km wind (around 10 kts) to the primary trough axis. This is
resulting in cells that at times have net motion near zero,
especially near mergers/outflow collisions driven by pulse storms
in the weak shear environment, lengthening the duration of this
heavy rainfall.

Although confidence in the evolution the next few hours is lower
than typical due to lack of model support, the recent HRRR has
started to capture the ongoing scenario and has exhibited a rapid
increase in coverage and amounts of QPF the next few hours. This
indicates that the environment will remain favorable for heavy
rainfall, and where storms train/stall, 2-3" of rainfall could
occur in less than 1 hour, with locally 4" possible by later this
morning. Despite elevated FFG from recent dryness, these rainfall
rates falling atop any more vulnerable soils or less-permeable
urban areas, could result in flash flooding.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6CTDGpysdS25mf6q1KvIInXWRn_m-k2LUW9IXXpzKQWXqhFp9f5QAxUfPAZIbAGIscEC= Nnoi-oKGS1ChFISn6RX9XMA$ for graphic product...

ATTN...WFO...HUN...LMK...LZK...MEG...OHX...PAH...

ATTN...RFC...ORN...TIR...NWC...

LAT...LON 37008724 36908570 36288544 35738569 35128660=20
34838778 34848882 35069004 35549099 36289126=20
36628992=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 130952
FFGMPD
VAZ000-NCZ000-SCZ000-GAZ000-TNZ000-KYZ000-ALZ000-131500-

Mesoscale Precipitation Discussion 0922
NWS Weather Prediction Center College Park MD
552 AM EDT Wed Aug 13 2025

Areas affected...northern Alabama through far northeast Tennessee

Concerning...Heavy rainfall...Flash flooding possible

Valid 130951Z - 131500Z

Summary...Showers and thunderstorms will expand and intensify
through the morning along a low-level convergence axis. Rainfall
rates within the stronger storms will reach 1-2"/hr, which through
training could produce 2-4" of rainfall. Flash flooding is
possible.

Discussion...The GOES-E IR imagery early this morning shows a slow
uptick in coverage of rapidly cooling cloud tops along a linear
boundary from northern AL through northeast TN. The colder and
deeper clouds are associated with thunderstorms evident on the
regional radar mosaic, with 1-hr rainfall measured via MRMS as
much as 1.5" beneath the stronger cells.

These thunderstorms are developing in response to intensifying
ascent impinging across robust thermodynamics. A mid-level trough
axis remains positioned well west of the region, which is leaving
pronounced low-to-mid level SW flow emerging from the Gulf and
advecting PWs above 2 inches northeastward, which is above the
90th percentile according to the SPC sounding climatology. This is
overlapped with a ribbon of MUCAPE 1000-2000 J/kg to provide an
environment favorable for heavy rain. Acting upon this airmass is
pronounced ascent driven by multiple ripples/weak shortwaves
moving through the flow combined with weak RRQ diffluence in the
tail of a jet streak positioned just NW of TN. Additionally, the
850mb LLJ has been steady from the WSW at 15-25 kts on the
regional VWPs, with the convergent nose providing an additional
mechanism for lift.

The result of this has been the growth and expansion of convection
the past hour or so, which is likely to continue for the next
several hours, potentially enhanced by an outflow boundary
dropping southeast as well. The high-res CAMs are struggling to
resolve the current activity, although the trends in the recent
HRRR, as well as the ARW and HREF-PMM support the increasing flash
flood risk. Rainfall rates will likely continue to surge to
1-2"/hr, and storms should move slowly northeast on mean 0-6km
winds of 5-10 kts. Concerning, however, is that propagation
vectors are aligned to the mean wind and also just 5-10 kts,
suggesting that cells will continue to regenerate along this
convergent nose and track northeast, a clear training signature
for the next several hours. While eventually the LLJ should veer
more to the west to reduce the training threat, until this happens
some areas could receive 2-4" of rainfall with locally higher
amounts (HREF neighborhood probabilities for 5" up to 15%).

Additionally, this rain could fall atop vulnerable soils where
3-hr FFG is as low as 1.5-2 inches, and the HREF exceedance
probabilities rise to 15-30%. Any training to produce locally
heavier rainfall across these soils or in any urban areas/more
sensitive terrain could produce impacts from flash flooding.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6FO-tex0-VR9730QWMzXkVuqEH1jhmntkVp9Buu4CWkRLPhxKB_RtcBPAICXYBmG8tFu= gq8yUGg2xBzt1sJcWcqYpyk$ for graphic product...

ATTN...WFO...BMX...FFC...GSP...HUN...JKL...MRX...OHX...RLX...
RNK...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 37148163 36968119 36488125 36048173 35678219=20
34928316 34528412 34298496 34008606 33918704=20
34098759 34878735 35708625 36238530 36618398=20
37068243=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 131205
FFGMPD
FLZ000-ALZ000-131630-

Mesoscale Precipitation Discussion 0923
NWS Weather Prediction Center College Park MD
804 AM EDT Wed Aug 13 2025

Areas affected...Southern AL...Western FL Panhandle

Concerning...Heavy rainfall...Flash flooding possible

Valid 131204Z - 131630Z

SUMMARY...Locally concentrated bands of showers and thunderstorms
with high rainfall rates will continue this morning across
portions of southern AL and the western FL Panhandle. Areas of
flash flooding will be possible, and especially for the more
urbanized locations.

DISCUSSION...The early morning GOES_E IR satellite imagery along
with surface observations shows a well-defined low-level vort
center and a fairly sharp surface trough advancing
east-northeastward to the east of Mobile Bay. This energy
continues to foster some deep convection around its southern flank
as very moist, convergent and unstable low-level flow advects
inland off the nearby Gulf of America and into portions of
southern AL and the western FL Panhandle.

MLCAPE values of 1500+ J/kg are pooled up across the western FL
Panhandle with PWs of 2.25+ inches, and this region in particular
will tend to be the primary focus area for additional bands of
convection over the next few hours. Rainfall rates up to 2
inches/hour are expected to continue, and some additional storm
totals amounts of up to 3 to 5 inches will be possible given
localized cell-training concerns with these bands of convection
that cross the Gulf Coast and advance inland.

Some locations that will likely be impacted by heavy rainfall this
morning include the Pensacola to Panama City corridor, and there
may be some localized urban flooding concerns that materialize.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_invE_lQ121_TUQZYWLQcGoIH8TrLgKC8MsN5EYCKBkQBGPb911rfyn-cD2VFDrD7m4I= ZULtbITHY847L4EDYbJs5PA$ for graphic product...

ATTN...WFO...MOB...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 31338613 30878515 30278497 29848528 30298638=20
30208758 30368800 30988802 31288733=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 131236
FFGMPD
LAZ000-TXZ000-131800-

Mesoscale Precipitation Discussion 0924
NWS Weather Prediction Center College Park MD
835 AM EDT Wed Aug 13 2025

Areas affected...Portions of Central to Northeast TX

Concerning...Heavy rainfall...Flash flooding likely

Valid 131235Z - 131800Z

SUMMARY...Slow-moving bands of heavy showers and thunderstorms
over portions of central to northeast TX should foster at least an
isolated threat for flash flooding going through midday.

DISCUSSION...The early morning GOES-E IR/WV satellite imagery
shows a well-defined mid-level vort center/shortwave gradually
crossing central to northeast TX which coupled with a surface
trough is helping to foster a broken axis of slow-moving shower
and thunderstorm activity.

Much of the convection is somewhat elevated, but is also focusing
within a convergent low-level flow regime around the southern
flank of the vort energy. MUCAPE value of 1000 to 2000 J/kg are
noted, with PWs of 2.0 to 2.25 inches helping to support rainfall
rates of up to 2.5 inches/hour with some of the stronger storms.

Weak and somewhat variable upwind propagation vectors are noted
around the southern flank of the vort energy, and this suggests an
environment that is conducive for backbuilding and locally
training showers and thunderstorms. Given this and the cooling
cloud top trends, this activity is likely to persist for at least
the next few hours across areas of northeast TX in particular.

Recent HRRR guidance suggests locally an additional 3 to 5 inches
of rain, and these additional rains are likely to result in
scattered areas of flash flooding going through midday.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-qz1LvMSVK_QYA8dDdv1DtyEoP5H8DRZDG0c1mOOvH26k0xmaMnQfbtdnBy3XMYwOzhF= hk36v9g2pQPJj_cCZgRvEcg$ for graphic product...

ATTN...WFO...FWD...SHV...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON 33639463 32899395 31729491 31389691 31899810=20
32479795 32759622=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 131426
FFGMPD
NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-WVZ000-132025-

Mesoscale Precipitation Discussion 0925
NWS Weather Prediction Center College Park MD
1025 AM EDT Wed Aug 13 2025

Areas affected...Portions of the Central Appalachians and
Mid-Atlantic

Concerning...Heavy rainfall...Flash flooding likely

Valid 131425Z - 132025Z

SUMMARY...Clusters of heavy showers and thunderstorms with locally
extreme rainfall rates will tend to expand in coverage over the
next several hours. Scattered areas of flash flooding will
gradually become likely, and especially later this afternoon
closer to the I-95 corridor of the Mid-Atlantic where an urban
flash flood threat is expected to evolve.

DISCUSSION...The latest satellite and radar imagery shows a band
of heavy showers and thunderstorms moving into northern WV, and
the latest trends show cooling cloud tops associated with this
activity.

This convection is associated with the southwest flank of
mid-level vort energy going into the central Appalachians which is
embedded within a very moist and moderately unstable environment.
MLCAPE values across northern WV and western MD, and areas east of
the Blue Ridge over the Mid-Atlantic, are locally on the order of
1000+ J/kg. However, the PWs are quite high and locally over 2
standard deviations above normal.

In fact, the 12Z RAOB soundings from KPIT and KIAD showed PWs of
1.86 and 2.22 inches respectively with tall skinny CAPE profiles
and elevated WBZ/freezing levels. This is strongly suggestive of a
very efficient and tropical environment that will promote highly
efficient processes for locally extreme rainfall rates that may
reach well into the 2 to 3+ inch/hour range.

Convection should tend to generally build in coverage over the
next several hours as this vort energy advances off to the east
across the central Appalachians and northern Mid-Atlantic region.
This will support heavy showers and thunderstorms advancing east
through central and northern WV, western MD and southwest PA in
the near-term.

However, as instability and convergent low-level flow becomes
better established this afternoon east of the Blue Ridge and into
the Chesapeake Bay region, there will likely be the development
and expansion of very heavy showers and thunderstorms across much
of northern VA, central to northeast MD and southern PA, including
areas along the I-95 corridor from Washington D.C. to Philadelphia.

The latest hires model guidance may be underplaying the rainfall
potential given the level of moisture that is in place, and there
will the influence of diurnal heating and orographics that will
also support an uptick in coverage of showers and thunderstorms.

Slow cell-motions and localized cell-training concerns coupled
with locally extreme rainfall rates may support some localized
rainfall totals of 3 to 5 inches. Areas of scattered flash
flooding will become likely in time, and this will include an
increasing urban flash flood threat near the I-95 corridor by
later this afternoon.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_BDgP8HIv5WDq8BcVl3dNGRRle70i2vNKdHEmFfl2ZsQtkVHeh08Ox-BZ5pMJwmlNwHH= O9WllFgWJyH_VkEemcudl3o$ for graphic product...

ATTN...WFO...AKQ...BGM...CTP...LWX...PBZ...PHI...RLX...RNK...

ATTN...RFC...RHA...TIR...NWC...

LAT...LON 41027601 40757482 39907456 39127511 38337647=20
37887805 37677977 37758073 38308145 39238129=20
39828054 40087923 40477767=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 131501
FFGMPD
VAZ000-NCZ000-SCZ000-GAZ000-TNZ000-ALZ000-132100-

Mesoscale Precipitation Discussion 0926
NWS Weather Prediction Center College Park MD
1100 AM EDT Wed Aug 13 2025

Areas affected...Portions of the TN Valley...Southern Appalachians

Concerning...Heavy rainfall...Flash flooding likely

Valid 131500Z - 132100Z

SUMMARY...Broken areas of heavy showers and thunderstorms will
continue to impact areas of the TN Valley and the southern
Appalachians going through the mid-afternoon hours. Additional
scattered areas of flash flooding are likely.

DISCUSSION...The latest GOES-E IR/WV satellite imagery along with
radar shows an expansive axis of broken showers and thunderstorms
extending from northern AL through eastern TN, northwest NC and
southwest VA. This activity continues to be focused along an
elongated axis of mid-level vort energy which is interacting with
a combination of very moist/unstable air and favorable orographics
near areas of higher terrain.

3-hour MLCAPE differentials off the latest RAP shows a notable
increase in instability across areas of eastern AL through
northern GA and into the eastern slopes of the southern
Appalachians. This instability along with moist southerly flow and
influence from differential heating boundaries ahead of the vort
energy should favor a general expansion of convection off to the
east going through the early and mid-afternoon hours.

PWs are locally over 2 standard deviations above normal and the
environment is strongly conducive for highly efficient rainfall
processes and potentially extreme rainfall rates. Areas of
greatest short-term concern may tend to be across northeast AL
through far southeast TN and northern GA where visible satellite
imagery shows a well-defined differential heating boundary and an
agitated CU field expanding in coverage.

Additional areas of convection near and just east of the southern
Appalachians from northwest SC and western NC into southwest VA
will be expected as well with locally very high rainfall rates.
Slow-moving cell-motions and the efficient tropical environment
will support locally 2 to 3 inch/hour rainfall rates and some
spotty storm totals of 3 to 5 inches by later this afternoon.

These rains are likely to support additional scattered areas of
flash flooding, and especially with locally wet/saturated
antecedent conditions.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_fOPX_jkq-ATXh6gnquYJd8ItVsuzAAcrDAqm9NSjWPAJQXv4XeY47xX1cYITDPhyCBU= d8SBy8rAec8NJrPkWaAKdeU$ for graphic product...

ATTN...WFO...BMX...FFC...GSP...HUN...MRX...OHX...RNK...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 37218083 36798037 35848104 34808215 34338299=20
33508461 33308591 33408728 33978761 34758682=20
35558556 36318387 36898240=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 131810
FFGMPD
MAZ000-NHZ000-VTZ000-CTZ000-NYZ000-NJZ000-PAZ000-140000-

Mesoscale Precipitation Discussion 0927
NWS Weather Prediction Center College Park MD
208 PM EDT Wed Aug 13 2025

Areas affected...Northeast PA...Northern NJ...Southeast
NY...Southern New England

Concerning...Heavy rainfall...Flash flooding possible

Valid 131808Z - 140000Z

SUMMARY...Increasing coverage of heavy showers and thunderstorms
may produce isolated to scattered areas of flash flooding going
through early this evening.

DISCUSSION...The early afternoon GOES-E visible satellite imagery
along with radar shows a gradual expansion of shower and
thunderstorm activity occurring across areas of northeast PA and
southeast NY. This convection is forming within an increasingly
moist and unstable airmass that is currently characterized by
MLCAPE values of 1000 to 2000 J/kg and PWs of generally near 1.75
inches.

Meanwhile, there is some upper-level support with the approach of
an upstream vort center over northern PA which coupled with
localized orographics and additional diurnal heating should favor
additional expansion of heavy shower and thunderstorm activity
over the next several hours which will include areas farther east
eventually inclusive of northern NJ, the northwest suburbs of New
York City, and adjacent areas of southern New England.

Rainfall rates with the stronger storms will be capable of
reaching 1.5 to 2.5 inches/hour, and with slow cell-motions and
some concerns for localized backbuilding and training of
convective cells, some rainfall totals by this evening may reach 3
to 4+ inches. This is generally supported by the 12Z HREF guidance.

The antecedent conditions across much of the region are on the dry
side, and this will mitigate the flash flood threat to an extent.
However, with such high rainfall rate potential and the localized
storm totals that may occur, there may be some isolated to
scattered flash flooding concerns. This will especially be the
case near areas of more rugged terrain such as the Poconos and
Catskills, along with any of the more urbanized locations to the
northwest of New York City and across southern New England.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9fDd8jSDjRgfW5Fk6LwTG4L9XjIxiNXUHagBbH6WsG2upyGby22f4yc1wrSTRm2bKh8e= _ly2h57bo7DeSV2bqFftXYI$ for graphic product...

ATTN...WFO...ALY...BGM...BOX...BTV...CTP...GYX...OKX...PHI...

ATTN...RFC...RHA...TAR...NWC...

LAT...LON 43657338 43497218 42507219 41807271 41257366=20
40897475 41037599 41497634 41827601 42297536=20
42907444=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 132019
FFGMPD
TNZ000-ALZ000-MSZ000-140215-

Mesoscale Precipitation Discussion 0928
NWS Weather Prediction Center College Park MD
418 PM EDT Wed Aug 13 2025

Areas affected...Mid-South

Concerning...Heavy rainfall...Flash flooding possible

Valid 132018Z - 140215Z

SUMMARY...Broken areas of slow-moving showers and thunderstorms
will continue to impact areas of the Mid-South going into the
evening hours. Additional isolated to scattered areas of flash
flooding will be possible.

DISCUSSION...The latest GOES-E visible satellite imagery shows
areas of slow-moving showers and thunderstorms with high rainfall
rates impacting portions of middle TN down through northwest AL
and northeast MS. This activity is embedded within a very noist
and unstable airmass with relatively divergent flow aloft and some
modest effective bulk shear facilitating some loose organization
of the convective cells.

MLCAPE values of 1500 to 2500 J/kg are in place with PWs of 2.0 to
2.25 inches and this will continue to yield high rainfall rates
capable of reaching 2 to 3 inches/hour with the more organized and
stronger storms. The cell-motions are generally off to the
south-southeast with the deeper layer flow, but the weak steering
currents should maintain slow cell-motions through the evening
hours.

Some additional expansion of convection may occur over the next
couple of hours as a combination of locally stronger instability
and outflow boundary collisions favor swaths of more convective
initiation. The latest hires guidance suggests areas of middle TN
down through northwest AL should tend to be the primary corridor
of heavier rainfall potential over the next few hours. This is
also where the 12Z HREF has some of the higher probabilities for
exceeding the 3-hour FFG values.

Locally an additional 3 to 4+ inches will be possible through this
evening, and these rains should continue to support concerns for
isolated to scattered areas of flash flooding.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9d-nBPNtLrDdhYGfgu8Q-VHVfmydrNgs6mrBm7TISgI5CsL5g1i0EBGnDbvBpOyFa_VC= N0nECrQk1P3SenIXCMa91bE$ for graphic product...

ATTN...WFO...BMX...HUN...JAN...MEG...OHX...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 36248717 36068624 35098609 33558685 32908804=20
32928901 33908931 35388849=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 132059
FFGMPD CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-WVZ000-OHZ000-14025=
5-

Mesoscale Precipitation Discussion 0929
NWS Weather Prediction Center College Park MD
455 PM EDT Wed Aug 13 2025

Areas affected...Portions of the Central Appalachians and into the Central/Northern Mid-Atlantic and Southern New England

Concerning...Heavy rainfall...Flash flooding likely

Valid 132055Z - 140255Z

SUMMARY...Clusters of heavy showers and thunderstorms with locally
extreme rainfall rates will continue going into the evening hours
across the interior of the central and northern Mid-Atlantic
region. Scattered areas of flash flooding will be likely which
will include strong concerns for urban flash flooding impacts near
and along the I-95 corridor.

DISCUSSION...The latest satellite and radar imagery shows clusters
of heavy showers and thunderstorms impacting central to northern
VA with some recent development noted across central MD. Meanwhile
farther off to the northeast, there are locally more organized
clusters of cold-topped convection seen impacting eastern PA.

The convection continues to be associated with the leading edge of
an elongated mid-level shear axis/vort center while interacting
with a very moist and strongly unstable airmass that has pooled
across much of the Mid-Atlantic region east of the Blue Ridge.
MLCAPE values of 2000 to 2500 J/kg are noted across central VA up
through southeast PA with some uptick in low-level moisture
convergence noted across the region over the last hour including
the middle and upper parts of the Chesapeake Bay area. The PWs are
very high and locally over 2 standard deviations above normal,
with values of 2.0 to 2.25 inches in place.

Early morning RAOB soundings showed tall skinny CAPE profiles and
elevated WBZ/freezing levels. This again strongly supports a very
efficient and tropical environment that will promote highly
efficient processes for extreme rainfall rate potential. Already
some of the stronger storm clusters have been producing rainfall
rates well into the 2 to 3 inch/hour range.

Convection should tend to generally build off to the east through
this evening into portions of the I-95 corridor from near
Washington D.C up through Philadelphia and then on up to at least
near the New York City metropolitan area. Meanwhile, the southwest
flank of the MPD area involving central VA back westward into the
central Appalachians will remain an area for convection as well
given proximity of a well-defined outflow boundary. Radar shows
locally concentrated areas of heavy thunderstorms across these
areas.

Localized/spotty additional rainfall totals of 3 to 4+ inches will
still be possible going through the evening hours. This will
likely promote scattered areas of flash flooding with concerns for
potentially considerable urban flooding impacts if some of the
heavier rainfall totals materialize over some of the larger
metropolitan areas.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_tydoPRFcqIscxgWPKUD8vbbjFq-kOOhQuFnWq8Sae1XG1Jm9JdMcOxb_26om-e5wmLK= eI0OVTd9MQ24M4l2Pio-dU0$ for graphic product...

ATTN...WFO...AKQ...ALY...BOX...CTP...LWX...OKX...PHI...RLX...
RNK...

ATTN...RFC...RHA...TAR...TIR...NWC...

LAT...LON 41947338 41577241 39937358 38537549 37567763=20
37528000 37888137 38608217 39168190 39228076=20
38897995 38717888 39177744 40247621 41017485=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 140046
FFGMPD
PAZ000-WVZ000-OHZ000-140415-

Mesoscale Precipitation Discussion 0930
NWS Weather Prediction Center College Park MD
845 PM EDT Wed Aug 13 2025

Areas affected...Far eastern OH...western PA...extreme northern WV

Concerning...Heavy rainfall...Flash flooding possible

Valid 140045Z - 140415Z

Summary...Locally training thunderstorm segments will maintain the
threat of isolated to scattered flash flooding through 4Z, with
localized 2-3" possible.

Discussion...Radar mosaic over the eastern OH Valley depicts two
segments of thunderstorms exhibitng training characteristics ahead
of a slow moving cold front approaching from the northwest. One
segment of thunderstorms containing estimated 2-2.5"/hr rainfall
rates over Youngstown, OH prompted a Flash Flood Warning as they
trained over the city.

These very efficient rainfall rates suggest the environment in the
prefrontal airmass remains quite favorable for efficient warm
rainfall production in any additional convection which develops.
Recent mesoanalysis data corroborates this idea, and suggests
1.75-1.8" PWATs (around the 97th percentile per the NAEFS),
1000-1500 J/kg MLCAPE (with no CIN), and 20 kts of effective shear
(oriented semi-parallel to the initiating boundary) are in the
vicinity of the ongoing activity even with loss of diurnal
heating. As such, the concern is for additional training segments
to develop in the short term with additional 2-2.5"/hr rates
possible. While the area has been dry as of late per NASA SPoRT,
recent runs of the HRRR suggest localized amounts of 2-3" will be
possible through 4Z, which could prompt additional instances of
flash flooding as 1 HR FFGs are in the 1.5-2"/hr range.

Asherman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8tK9BEc_yBGSTwd_WQUg7sobBt85XDGfZudaEYMCp3tjvmwXkPsw9TQprCCKAd_tiUla= jBx1epnCvRek3fRM759olW4$ for graphic product...

ATTN...WFO...CLE...CTP...PBZ...

ATTN...RFC...RHA...TIR...NWC...

LAT...LON 41477986 41267878 40707858 40297896 40117970=20
40228090 40618133 41228092=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 140421
FFGMPD
MNZ000-SDZ000-NDZ000-140857-

Mesoscale Precipitation Discussion 0931
NWS Weather Prediction Center College Park MD
1220 AM EDT Thu Aug 14 2025

Areas affected...Northeast SDak...Southeast NDak...Far
West-central MN...

Concerning...Heavy rainfall...Flash flooding possible

Valid 140417Z - 140857Z

SUMMARY...Regenerative warm-air advection thunderstorms will be
slow to move initially resulting in spots of 2-3.5" and possible
localized flash flooding, before shifting east-northeast toward
early morning.

DISCUSSION...GOES-E 10.3um and KABR RADAR show a few bands of
thunderstorms across northeast South Dakota into far southeast
North Dakota with downstream cirrus and lighter showers extending
into western Minnesota. GOES-E WV and RAP analysis shows an
exiting and flattening shortwave within synoptic scale ridging
across south central MN into northeast IA, while a stronger
shortwave and associated linear convective complex along the
southern flank of the wave starting to reach central SDak and Sand
Hills of NEB. The low-level jet has responded while recently
strengthening to 45-50kts at 850mb with solid veered 925-700mb
profile along/ahead of the approaching wave. This is obliquely
intersecting the lingering boundary left in the wake of the prior
wave. Recent strengthening and increasing deeper layer moisture
with total PWat values up to 1.75" helps to differentiate the
isentropic boundary across the southern portion of the Red River
Valley; and given increasing core of the unstable air north-south
axis generally along 98-99W with values of 2000-2500 J/kg MUCAPEs.
The stronger moisture flux convergence is increasing rainfall
efficiency for the thunderstorms. Rates of 1.5-2"/hr are starting
to become more common with the recent cooling noted in the
convective tops.=20

Along with the strengthening flux convergence, the veered inflow
is also supporting southwestward upwind propagation and given the
sharpness of the ridging between the two mid-level waves, the
deeper layer steering is also slackened to reduce eastward cell
motions as well. This has resulted in back-building and localized
training of downdrafts locally along the best isentropic upglide
ascent plane to increase duration over an hour with repeating that
may allow for localized 2-3.5" totals over the next few hours.=20
Hourly rates are near the hourly FFG, but those locally higher
totals have a good potential to exceed the 3hr FFG values which
range from 1.5-2.5" across the area of concern. As such,
localized flash flooding is considered possible for the next few
hours. As the MCS/shortwave passes, winds will remain strong,
but likely veer further and increase forward propagation into
northwest and west-central MN...but with the decrease in local
duration potential for exceedance will diminish.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4OdAPkGsM-ff6LYoFoLjaaDhOcApoe6CL-SGFGv2L4c2SAtoFdHry8aUUo1Gaz8cSaah= 1thAPr2Ybi-eIdpKsf40DnQ$ for graphic product...

ATTN...WFO...ABR...FGF...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 46839674 46239622 45649600 45059601 44669643=20
44739700 44939737 45409775 45799795 46059800=20
46439794 46819753=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 141834
FFGMPD
VAZ000-NCZ000-SCZ000-150030-

Mesoscale Precipitation Discussion 0932
NWS Weather Prediction Center College Park MD
233 PM EDT Thu Aug 14 2025

Areas affected...SC Pee Dee...Southern and Eastern NC...Southeast
VA

Concerning...Heavy rainfall...Flash flooding possible

Valid 141833Z - 150030Z

SUMMARY...Clusters of heavy showers and thunderstorms will be
developing and expanding in coverage going through the afternoon
hours. High rainfall rates will pose a threat for scattered areas
of flash flooding.

DISCUSSION...A well-defined mid-level vort center with a weak
surface low and associated trough is seen advancing northeast
across central and eastern SC which will be lifting up across
southern and eastern NC going through the afternoon hours. This
energy will be interacting with increasing boundary layer
instability and the pooling of tropical moisture for expanding
clusters of heavy showers and thunderstorms.

MLCAPE values have already increased to 2000 to 3000 J/kg across
eastern NC with the aid of stronger solar insolation and some
additional uptick and expansion of this instability is expected
over the next couple of hours. PWs are very high from the SC Pee
Dee region up through eastern NC with values of 2.25 to 2.5 inches
noted.

The strong instability and deep moisture parameters are expected
to favor showers and thunderstorms with extremely high rainfall
rate potential, with some of the stronger convective cells
potentially yielding rainfall rates 2 to 4 inches/hour. Some
uptick in low-level moisture convergence around the eastern flank
of the aforementioned vort/low center will help to also facilitate
some of these higher rainfall rates and a general uptick in
convective organization by later this afternoon.

By early this evening, there will also be some attention focused
across southeast VA as a cold front settling southward toward the
Hampton Roads/Tidewater region begins to interact with this low to
mid-level energy lifting northeast across eastern NC. Stronger
low-level convergence and an improvement in the instability
profile by this evening will eventually drive an increasing threat
of showers and thunderstorms with high rainfall rates.

Expect some localized rainfall totals of 3 to 5 inches to be
possible given the high rainfall rates, and potential for some
spotty cell-training. Much of the hires model CAM guidance
suggests southern and eastern NC will be the area of greatest
concern through 21Z and 00Z, but portions of southeast VA in this
time frame may begin to see the aforementioned uptick in
convection that could drive a couple inches of rain, with more
potential for heavy rainfall afterwards going well into the
evening hours.

Scattered areas of flash flooding will be possible which will
include some localized urban flooding concerns as well.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-r3hLWvM7_EufC2TIGrholpHMsBWgelijqt1V4zV-j2XAu0MhWGq9L2PSfVfiJRmqGJ3= PvXwMw6lOZd6TQZVa90KqxM$ for graphic product...

ATTN...WFO...AKQ...ILM...MHX...RAH...

ATTN...RFC...ALR...RHA...NWC...

LAT...LON 37017644 36827582 35817540 35187546 34677613=20
34367732 33607810 33337891 33417949 34097982=20
34527964 35467797 36667711=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 141840
FFGMPD
NMZ000-AZZ000-150039-

Mesoscale Precipitation Discussion 0933
NWS Weather Prediction Center College Park MD
240 PM EDT Thu Aug 14 2025

Areas affected...western New Mexico, eastern Arizona

Concerning...Heavy rainfall...Flash flooding possible

Valid 141839Z - 150039Z

Summary...Isolated to scattered thunderstorm activity will expand
in coverage and drift slowly through the afternoon hours.=20
Isolated instances of flash flooding are expected with this
activity.

Discussion...Daytime heating and weak/modest ascent associated
with nearby mid-level vorticity maxima were aiding on a gradual
deepening of convection this afternoon. So far, the deeper cores
have materialized on an isolated basis near terrain-favored
peaks/ridges across southwestern New Mexico. Weak southerly flow
aloft has contributed to slow, erratic storm motions so far, and
PW values (ranging from 0.75 in NM to 1.4 in southern AZ) are just
high enough to promote wetting rainfall and a quick burst of
around 0.5 inch rainfall amounts beneath the more dominant
activity.

With continued daytime heating and surface-based destabilization,
the ongoing scenario is expected to evolve slowly, with storms
expected to expand in coverage. Some of the heavier rainfall
could occur atop burn scars and/or low-lying terrain that could
locally promote excessive runoff and flash flooding. Models
suggest that the flash flood risk should primarily be diurnally
driven, but should also persist beyond 00Z/6p MDT this evening.=20
The heaviest rain rates should occur across portions of Arizona
where higher moisture content is located, although local 1 inch/hr
rain rates could materialize across the entire discussion area
this afternoon.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-YGmfRGNxvHvUiX-DZREdW0C8PK7aACwabYmUjTRcVK6OR6c9jBmz82mwdp6gKo9m6i2= qotXpCHWP55b8lcmospacNM$ for graphic product...

ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...VEF...

ATTN...RFC...FWR...STR...NWC...

LAT...LON 36731249 36200907 34520743 32930680 32190705=20
31510850 31461011 31811123 33481275 35261335=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 141928
FFGMPD
MDZ000-VAZ000-DCZ000-142227-

Mesoscale Precipitation Discussion 0934
NWS Weather Prediction Center College Park MD
328 PM EDT Thu Aug 14 2025

Areas affected...portions of Maryland and vicinity

Concerning...Heavy rainfall...Flash flooding possible

Valid 141927Z - 142227Z

Summary...Isolated instances of flash flooding cannot be ruled out
as thunderstorms merge and produce heavy rainfall over the next
couple hours.

Discussion...Recent radar mosaic imagery depicts expanding
convective coveage across Maryland from near Baltimore southward
along western sides of the Chesapeake Bay to near Waldorf and
Leonardtown. While initial development has been propagating at
around 10-15 knots, the orientation of cells amid weak low-level
shear should enable a greater frequency of cell mergers over the
next couple hours. The airmass supporting thunderstorm
development is abundantly moist (2+ inch PW values, 3000 J/kg
SBCAPE), suggesting that local rain rates could reach 2 inches/hr
in a few spots. This should promote flash flood potential -
especially in urban areas across central/eastern Maryland that
experience heavy rainfall.

The evolving flash flood threat should be relatively brief. As
storms migrate from north to south, rain cooled air/low-level
stabilization should take hold and result in an eventual decrease
in convective coverage after around 22Z or so.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6MBRT_ll1e9vlawqn4YbrK-IEUBJYQ-VYIrzPiiA8oo3jmi7lJdmtMp_iJCN7phgWfN7= 7m5ZqSm6qSl8Q82TIkaO05Y$ for graphic product...

ATTN...WFO...AKQ...LWX...PHI...

ATTN...RFC...RHA...NWC...

LAT...LON 39697640 39307595 38487582 37957617 38067695=20
39067718 39667707=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 150028
FFGMPD
VAZ000-150327-

Mesoscale Precipitation Discussion 0935
NWS Weather Prediction Center College Park MD
828 PM EDT Thu Aug 14 2025

Areas affected...southeastern Virginia

Concerning...Heavy rainfall...Flash flooding possible

Valid 150027Z - 150327Z

Summary...Flash flooding remains possible for a few more hours,
though an overall downward trend in convective coverage is
expected through 03Z/11p EDT.

Discussion...Flash flood potential continues across southeastern
Virginia. Scattered thunderstorms continue to migrate very slowly
ahead of a front draped across the area (subjectively analyzed
from near Danville, VA to Salisbury, MD). Widespread convective
overturning has occurred across North Carolina that should serve
to limit any renewed convective development here. Some
overturning has occurred near Wakefield and Virginia Beach,
although 80s F surface temps just north of that area (near
Williamsburg and Richmond) was continuing to sustain scattered
thunderstorm activity. Areas of 1 inch/hr rain rates were still
being observed, which isn't surprising given the 2+ inch PW values
within the pre-convective airmass. These rates still support
localized flash flood potential - especially in low-lying and
urbanized areas of southeastern VA.

The ongoing flash flood threat should persist for another couple
hours or so. Widespread convective overturning continues to
exhaust surface-based instability across the region. Meanwhile,
lack of surface heating and eventual progression of a front
through the region should gradually limit the spatial extent of
opportunity for renewed convection. Much of the flash flood
threat should end after 04Z/midnight EDT or so.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7-C2NzmM7TLaKRAUgzLcqdmi842Rw-MCr_ucu5-IQbSHgysGXGev2qcXx7NqcTdyleZN= FXyAqHRQwHoZ0H8uCh3k4tU$ for graphic product...

ATTN...WFO...AKQ...RNK...

ATTN...RFC...ALR...RHA...NWC...

LAT...LON 37657659 36967546 36557678 36577833 37097851=20
37597787=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 150501
FFGMPD
AZZ000-150930-

Mesoscale Precipitation Discussion 0936
NWS Weather Prediction Center College Park MD
100 AM EDT Fri Aug 15 2025

Areas affected...Central Arizona...

Concerning...Heavy rainfall...Flash flooding possible

Valid 150500Z - 150930Z

SUMMARY...Slow moving thunderstorms with 1.5-1.75"/hr rates and
localized totals to similar values may pose localized widely
scattered incident or two of flash flooding overnight.

DISCUSSION...Recent GOES-W 10.3um and KIWA RADAR depict an
increase in convective activity over the last hour or so through S
Yavapai into eastern Maricopa county. Evening outflow boundary
coming off the San Francisco Plateau had lost much of the driving
convective activity through the early overnight period and settled
into the Sun Valley. Recent VWP and surface observations noted a
slight uptick in southerly and southwesterly flow solidly
increasing convergence along the boundary. GOES SWIR, suggests
the leading edge may still be dropping south across SE Maricopa
toward northern Pinal, but in the core of the return southerly
flow strong ascent as seen tops cool to below -60C, tapping the a
remaining small pool of unstable mid-level air with MUCAPEs
analyzed around 1500-2000 J/kg per the RAP. VWP shows 10-15kts of
flow at 850mb/cloud providing the solid moisture flux into the
developing cells. CIRA LPW notes core of enhanced surface to
850mb moisture is further west than the 850-700mb axis; which
further tilts eastward across Pinal into central Gila county in
the 700-500mb layer; so peak influx is about across central
Maricopa into south-central Yavapai and with vertical totaling of
about 1.5" on 15kts should support 1.5-1.75"/hr rates.=20

Steering from 700 per VWP is weak and out of the west, but again
backs more southerly through the core of the cells but still about
5-10kts allowing for some tilting to keep the downdraft collapsing
on the updrafts, but also support slow cell motions to allow for
localized accumulation for a spot of 2" possible. Still,
short-term rates in proximity to hard desert soils or urban
centers will result in increased runoff and possibility for flash
flooding through the overnight period.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7FvvK56e6K5TSG1JdEfE87sCaF2F7JrDjPP55FhikLxbpuNCDcnYxkxbfcUbMapzkdcQ= cAqL9qrjBPKcaFXlKqMHvt0$ for graphic product...

ATTN...WFO...FGZ...PSR...

ATTN...RFC...STR...NWC...

LAT...LON 35051277 34891219 34581182 34161146 33661093=20
33391088 33121126 33241210 33611265 34241306=20
34751312=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 151717
FFGMPD
TXZ000-152315-

Mesoscale Precipitation Discussion 0937
NWS Weather Prediction Center College Park MD
115 PM EDT Fri Aug 15 2025

Areas affected...Deep South Texas

Concerning...Heavy rainfall...Flash flooding possible

Valid 151715Z - 152315Z

SUMMARY...Slow-moving and locally very heavy showers and
thunderstorms this afternoon are expected to produce some concerns
for mainly urban flash flooding across far southern TX.

DISCUSSION...The latest GOES-E visible satellite imagery along
with radar data shows some uptick in shower and thunderstorm
activity across far south TX near the Rio Grande River and around
the Brownsville metropolitan area. This is associated with the
poorly organized tropical disturbance (98L) seen approaching far
northeast MX and south TX.

There is a fair amount of mid-level vort energy associated with
this system, and this coupled with at least some locally focused
low-level moisture convergence and moderate instability should
yield an uptick and expansion of heavy shower and thunderstorm
activity going through the afternoon hours.

MLCAPE values of 1500 to 2500+ J/kg are in place and this coupled
with very high PWs of 2.25 to 2.5 inches should yield at least
some concentrated convective cells with rainfall rates capable of
reaching 2 to 3 inches/hour.

The hires model guidance overall is quite limited with the heavy
rainfall potential across far southern TX, but there have been
some increasingly wetter trends noted with the recent RRFS
guidance, with some potential for locally slow-moving
bands/clusters of convection impacting areas near and west of
Brownsville over the next few hours.

Given this and the recent radar and satellite trends, some spotty
rainfall totals of 3 to 5+ inches will be possible where the more
focused storms set up. While widespread flash flooding is not
expected, there may be localized urban flash flooding impacts.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4TRPF31fxLUTbLXNVZxHKpjf90EmIZkps6vWGVK8LLJLGTbpksIHZXsyxkH71kqD_v3S= zS4Xiniosd0osghOmBb3op4$ for graphic product...

ATTN...WFO...BRO...

ATTN...RFC...FWR...NWC...

LAT...LON 27009837 26929771 26799732 26409704 25939706=20
25779745 25999837 26369892 26739885=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 151733
FFGMPD
LAZ000-152230-

Mesoscale Precipitation Discussion 0938
NWS Weather Prediction Center College Park MD
132 PM EDT Fri Aug 15 2025

Areas affected...South-Central to Southeast LA

Concerning...Heavy rainfall...Flash flooding possible

Valid 151730Z - 152230Z

SUMMARY...Heavy showers and thunderstorms over south-central to
southeast LA may result in at least an isolated threat of flash
flooding going through the afternoon hours. This will include some
urban flash flooding concerns to the New Orleans metropolitan area.

DISCUSSION...Slow-moving showers and thunderstorms with very high
rainfall rates approaching 3 inches/hour will likely continue over
the next few hours across portions of south-central to southeast
LA.

A localized band of stronger low-level convergence combined with
strong instability characterized by MLCAPE values of near 3000
J/kg will support convective sustenance in the near-term with aid
also from localized outflow boundary collisions which will tend to
facilitate new convective development.

The latest hires model guidance, especially led by the RRFS
solutions, suggests some potential for 3 to 5 inch rainfall totals
by early this evening. These high rates and localized storm totals
may impact areas near or into the New Orleans metropolitan area
over the next few hours. Therefore, at least an isolated and
mainly urban flash flood threat will exist as this axis of heavier
showers and thunderstorms continues.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-bCYGL1cYWvcgZH6eSJjVzPr2MB5ysT6bxXQVeqmSTpGZfZRboQB1UoXrJYGkG_dzN1L= lQ0lGtc1R3Xe24_1eLSN31s$ for graphic product...

ATTN...WFO...LCH...LIX...

ATTN...RFC...ORN...NWC...

LAT...LON 30709171 30489015 30088966 29568975 29349039=20
29769181 30219226=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 151906
FFGMPD
TXZ000-NMZ000-AZZ000-UTZ000-160100-

Mesoscale Precipitation Discussion 0939
NWS Weather Prediction Center College Park MD
304 PM EDT Fri Aug 15 2025

Areas affected...Southern UT...Much of AZ...Western and Central NM

Concerning...Heavy rainfall...Flash flooding possible

Valid 151904Z - 160100Z

SUMMARY...Increasing coverage of locally heavy showers and
thunderstorms can be expected going through the afternoon hours.
Isolated to scattered areas of flash flooding will be possible,
and especially given slow cell-motions and potential for impacts
around the more sensitive dry wash, burn scar and slot canyon
locations.

DISCUSSION...The midday GOES-W visible satellite imagery shows
three well-defined mid-level vort centers collectively embedded
within deeper layer south-southwesterly mid-level flow over AZ and
NM. The energy over the northern part AZ will be gradually
approaching areas of southern UT over the next few hours which
coupled with favorable orographics and an uptick in boundary layer
instability should help drive the development and expansion of
some shower and thunderstorm activity here.

However, the more notable threats for stronger convection will
likely be with the energy over southeast AZ and southwest NM where
there is already locally strong diurnal heating and presence of an
instability gradient/differential heating boundary that will help
facilitate convective initiation.

SBCAPE values over southeast AZ are locally over 1500 J/kg and
close to 1000 J/kg along the northern AZ/southern UT border. The
PWs are rather concentrated in the 500/700 mb layer based off the
CIRA-ALPW data, and especially over southeast AZ and into
west-central to southwest NM.

On a regional basis, there should be the development and expansion
of shower and thunderstorm activity that will be rather
slow-moving and locally anchored near areas of higher terrain.
More concentrated cells will be possible in close proximity to the
vort centers as they lift off to the north and northeast. This
convective evolution is supported by the latest hires WoFS
guidance.

Rainfall rates of up to 1 inch in as little as 20 to 30 minutes
will be possible. However, some localized storm total amounts of 2
to 3+ inches may occur given the slow cell-motions and
terrain-focused activity. Some of the hires CAM guidance led by
the NAM Conest, FV3 LAM and RRFS supports this.

This will drive isolated to scattered areas of flash flooding
potential which will mainly be focused on the dry wash, burn scar
and slot canyon locations where there are greater sensitivities
and concerns for enhanced runoff.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4Q1S0K-RnM736tvhuutPocJgepsOULovU9Yitc0OtHMiCN5iD6Di2e1FRQ_RNmE0xLoq= gSgGBqg6-erfvWHJE4uqyBw$ for graphic product...

ATTN...WFO...ABQ...EPZ...FGZ...GJT...PSR...SLC...TWC...VEF...

ATTN...RFC...FWR...STR...NWC...

LAT...LON 38381223 38251075 37660985 37060924 36410774=20
36040614 35350532 34380504 33280509 32460503=20
31800532 31430580 31300655 31210772 31040956=20
31221120 32011207 33351214 34561257 35731323=20
37601317=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 151910
FFGMPD
NCZ000-SCZ000-GAZ000-TNZ000-ALZ000-160000-

Mesoscale Precipitation Discussion 0940
NWS Weather Prediction Center College Park MD
309 PM EDT Fri Aug 15 2025

Areas affected...northern AL/GA into adjacent portions of TN/NC/SC

Concerning...Heavy rainfall...Flash flooding possible

Valid 151905Z - 160000Z

Summary...Increasing thunderstorm coverage into the late afternoon
with locally heavy rainfall (as high as 2-3"/hr rates) may result
in isolated to scattered instances of flash flooding.

Discussion...A distinct upper-level trough (most apparent above
400 mb, associated with a PV anomaly apparently originating from
cyclonic wave breaking) centered near the Midsouth is allowing for
greater coverage of convection into downstream portions of TN/AL.
The mesoscale environment is characterized by high tropospheric
moisture (1.7-2.1" PWs, at or above the 90th percentile per FFC
sounding climatology), effecitve bulk shear (25-30 kts, also at or
above 90th percentile), and plentiful instability (SBCAPE
2500-4500 J/kg). While the environment is lacking a surface
boundary or focusing mechanism to efficiently organize convection,
the increased coverage of cells alone will be sufficient to result
in cell mergers and outflow boundary collisions to result in
localized training/repeating of heavy rainfall rates (with as much
as 2-3"/hr with the strongest updrafts, as deep layer mean flow of
only 5-10 kts allows for longer residence times of assicated
downdrafts).

Hi-res CAMs are in relatively good agreement concerning both the
precise spatial overlap of heavier convection (per HREF EAS 0.5"
exceedance probs of 15-25% from east-central AL through northeast
GA into adjacent portions NC/SC) and chances for localized heavy
totals (40-km neighborhood 3" exceedance probs of 15-35%,
generally along and north of the highest EAS probs). 3-hr FFGs
across the region generally range from 2.0-3.0", suggesting
relatively high chances for localized FFG exceedance (HREF 40-km
probs for 3-hr FFG exceedance equating to 15-35% as well). Given
the overall favorable environment and recent observational trends,
isolated to scattered instances of flash flooding are possible
through dusk. While some convection may linger into the evening
hours, coverage and intensity should be diminishing overall with
the dry air/subsidence associated with the backside of the upper
trough ending heavy rainfall for northern/western portions (i.e.
AL/TN) of the MPD first.

Churchill

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7LFF506LU6Y4ZM3Y29zYooJXw8vlpISsn8eYKNcHiiZ-FbtuEOKGzRZwI9XeJD2GPxcO= Pef0tkOtvzQleUUW5Wtzoag$ for graphic product...

ATTN...WFO...BMX...CAE...FFC...GSP...HUN...MRX...OHX...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 36428474 36028423 35668359 35598242 35298191=20
34648208 33928253 33518282 33208322 33088357=20
32998420 33078483 33208536 33158588 33148642=20
33608692 34498655 35468649 35828557 36338516=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 160245
FFGMPD
AZZ000-160730-

Mesoscale Precipitation Discussion 0941
NWS Weather Prediction Center College Park MD
1044 PM EDT Fri Aug 15 2025

Areas affected...South-central to Southeast Arizona...

Concerning...Heavy rainfall...Flash flooding possible

Valid 160245Z - 160730Z

SUMMARY...Slow moving thunderstorms to track slowly southwest
perhaps with short-term training/repeating resulting in localized
2"+ totals and possible localized flash flooding conditions.

DISCUSSION...Fading GOES-W Visible imagery loop shows two NW to SE
outflow boundary arcs across AZ, one up on the San Francisco
Plateau, the other through the Sonoran Desert into southeast AZ
and northeast Sonora, Mexico. GOES WV suite continues to depict a
deep long wave trof with slight negative tilt orientation across
Southern California with broadening diffluent region of
southwesterly flow across much of the Colorado River Basin into AZ
providing deep layer divergence across the region.=20

As sunset was approaching, increasing southerly flow off the Sea
of Cortez surged moisture through the surface to 850mb layer
across Mexico into south-central AZ. This increased moisture flux
convergence along the boundary providing solid isentropic ascent
to break out clusters of thunderstorms. The dominant reaching -70C
across southern Pima county. RADAR and EIR continues to show expansion/intensification within the cluster. RAP analysis
denotes that MUCAPE values remain around 2000-2500 J/kg,
especially further west to fuel these cells. LLJ of 25kts slowly
reduces along the eastern edge of the jet and propagation vectors
suggest slow southeastward evolution along the stalling outflow
boundary (though the boundary will likely kick southward with time
given cold pool generation). Surface Tds in the low to mid 60s
and total PWats through the lower cloud support PWat values near
1.5-1.75" and should support rates of 1.75"/hr, occasionally
ticking up to 2" where cores can merge for short duration.=20=20
Duration is likely to be 1-2 hours with similar rates, so
localized 1.5-2.5" totals are possible across south-central
Arizona and toward the Santa Cruz county border with Mexico. As
such, localized incidents of flash flooding will remain possible
through the early overnight period.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7S_MaR-y33KOHbIuy4c0dLYta8rZ8c4IVyIuO3A1_RE6ZyVrwS4ykbm1t46q908Jp_-J= EB9quBP7Ee5rPttqbs-aWGw$ for graphic product...

ATTN...WFO...TWC...

ATTN...RFC...STR...NWC...

LAT...LON 32511194 32261127 31751065 31441001 31261001=20
31251064 31301126 31451163 31671225 31931252=20
32351247=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 160311
FFGMPD
AZZ000-160830-

Mesoscale Precipitation Discussion 0942
NWS Weather Prediction Center College Park MD
1110 PM EDT Fri Aug 15 2025

Areas affected...Western to Central Arizona...

Concerning...Heavy rainfall...Flash flooding possible

Valid 160310Z - 160830Z

SUMMARY...Expanding convective complex to slowly lift north,
intersect with older outflow boundary. Cells with rates of
1.5"/hr and slow motions may allow for localized 2"+ totals and
possible localized incidents of flash flooding overnight.

DISCUSSION...Fading GOES-W Visible and 3.9m SWIR shows a pair of
outflow boundaries from earlier evening convective activity, both
extending arched from NNW to SE. The northern one remains along
or just off the Mogollon Rim across northern Arizona with a second
extending from east of Blythe across the Sonoran Desert southwest
of Phoenix toward Pima county. GOES-W WV suite along with GOES
AMVs show deep layer upper-level trough over Southern California
with a weak negative tilt as a subtle shortwave feature rolls
eastward into the Cochella Valley toward the Colorado River
Valley. This broad southwesterly flow is orthogonal to the
orientation of the outflow boundaries, so all convection has been
generally developing and back-shearing northeastward reducing
forward overall propagation (at least in the short-term period).=20

Recent stronger LLJ through out of the Sea of Cortez has surged north-northwestward across the Sonoran desert (using CIRA LPW and
RAP analysis) with 15-20kts, responding to the advancing shortwave
feature. Mid-level steeper lapse rates provide solid instability
for stronger/deeper thunderstorm activity along the the southern
boundary with MUCAPE values of 2500-3000 J/kg analyzed. The slug
of moisture is estimated per CIRA LPW and RAP to be around 1.5"
with most in the sub-700mb layer to allow for efficient warm cloud
processes for stronger cells.=20

Current 10.3um and RADAR mosaic show a few stronger clusters with
the broadest up/downdraft along the Mohave/La Paz county line just
east of the California border, as well as newer cells downstream
along the Yavapai border. Given instability and moisture flux
rates of 1.5-1.75"/hr are probable (along with some hail
generation). As the shortwave lifts northeast, deeper layer mean
southwesterly flow will allow for northeastward motions back
toward the western Mogollon Rim, perhaps intersecting with areas
affected earlier. Scattered incidents of 1.5" are probable, with
an few more isolated totals of 2-2.5" with higher probability
across Yavapai county per recent HRRR, WoFS and 00z Hi-Res CAM
solutions.

A few back-sheared convective columns can be seen north across E
Mohave with the northern boundary, but most of those are generally
weaker and widely scattered in coverage, but should still slowly
propagate southwest eventually intersecting/integrating with the
developing clusters moving northeast with the mean short-wave
ejection. Similarly, these intersections/mergers will pose the
greatest risk for flash flooding in the slopes of the Mogollon Rim
throughout the overnight period, resulting in possible widely
scattered incidents of flash flooding.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_SuwBf_PKHENhYETvwNv97alIgQuN-ADZKRki_oRwhmMzJ2-VMY8bvA0tr3f6pQPE9e2= a9M0x3cwbw8pt7T2mnLiork$ for graphic product...

ATTN...WFO...FGZ...PSR...VEF...

ATTN...RFC...STR...NWC...

LAT...LON 36341314 35701240 35241150 34721133 34171142=20
33751208 33561283 33591383 33761407 34291410=20
35361417 35981373=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 160650
FFGMPD
MNZ000-SDZ000-161200-

Mesoscale Precipitation Discussion 0943
NWS Weather Prediction Center College Park MD
249 AM EDT Sat Aug 16 2025

Areas affected...South-central & Eastern SD...Southwest MN...

Concerning...Heavy rainfall...Flash flooding possible

Valid 160650Z - 161200Z

SUMMARY...Very progressive squall QLCS will have strong moisture
flux for intense rainfall production with sub-hourly totals of
1.5-2"; though best risk for flash flooding will be flanking line
training for spots of 2-3" over hard/impermeable soils.

DISCUSSION...GOES-E WV suite shows a compact 80kt 3H jet streak
across the North/South Dakota border which continues to strengthen
a compact shortwave within its broad right entrance region. 06z
Surface analysis shows an inverted wave inflection along the
strongest DPVA/divergent region within the southeast quadrant of
the wave across central SDak. A surface stationary front extends
east into west-central MN before angling north toward Duluth and
is directing strong and very moist low level flow to enhance very
strong moisture flux convergence. Additionally, steep lapse rates
with the very rich moisture at the surface in the mid to upper
70s, supports 4500-5000 J/kg and the combination is result in very
broad and strong updrafts across south-central SDAK at this time.=20
Numerous overshooting tops below -75 to -80C denotes the vigor of
the updraft including their width.=20=20

As noted, the surface Tds are well above normal and loading the
low-level profile to support over 2-2.25" total PWat values and
given the strength of the LLJ at 30-40kts, the lower cloud
moisture loading is fairly high, even though some will be lost to
hail production, there will be efficient rainfall production,
further increasing with time/maturity of the squall. So while the
limiting factor of forward speed/propagation for duration, the
broad downdrafts will allow for some overall sub-hourly totals of
1.5-2". Additionally, the strength of the bow is also supporting
a veering low level profile and tight anticyclonic rotor along the southwesterly flanking line. VWP and RAP analysis suggest that
flanking axis is likely to trail and has some solid angle toward
the initial bow/squall line to add an additional duration of heavy
rainfall. As such, an axis of enhanced totals of 2-3.5" in 2-3
hours is becoming increasingly probable across south-central into
eastern SDak and eventually into SW MN.

Hydrologically, the area has been in a solid drought and ground
conditions well below average running at about 10-25th percentiles
with 0-40cm at 10-25%. This makes the soils hard and reduce
infiltration particularly in the strength of the instantaneous
rates sub-hourly totals...with 03z HRRR solutions suggesting 15min
totals ranging from 1.5 to as high as 2", this suggests fairly
quick totals with little/no infiltration, increasing run off. As
such, localized flash flooding is considered possible, especially
if the flanking line repeats behind the initial line.=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-Vh8PTkf1F0MIOfoehoFF2Lew4lcse0AoUz4MXvZw3BLK6bC0oHDF6U3CZ4_I-m3HXcd= trvGEa8u2TMdIZfYq6fPTAo$ for graphic product...

ATTN...WFO...ABR...FSD...MPX...UNR...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 45669531 45439422 44779398 44209493 43689625=20
43229806 43040054 43190186 44050077 44769940=20
45279730=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 161207
FFGMPD
WIZ000-MNZ000-IAZ000-SDZ000-NDZ000-161805-

Mesoscale Precipitation Discussion 0944
NWS Weather Prediction Center College Park MD
805 AM EDT Sat Aug 16 2025

Areas affected...Northeast SD...Central/Southern
MN...Western/Central WI

Concerning...Heavy rainfall...Flash flooding possible

Valid 161205Z - 161805Z

SUMMARY...A strong MCS will continue to advance off to the east
this morning across the Upper Midwest while fostering heavy
rainfall and at least an isolated threat for mainly urban flash
flooding going through midday.

DISCUSSION...The early morning GOES-E IR satellite imagery shows a
strong cold-topped MCS advancing across eastern SD and much of
central and southern MN. A well-defined MCV is embedded within the
convective mass, and this energy will be advancing east this
morning through portions of eastern MN and into western WI.

A very moist and unstable environment is in place which is being
aided by a 40 kt southwest low-level jet aiming up across
northwest IA and southwest MN. MUCAPE values are on the order of
2000 to 3000 J/kg over southern MN currently, and this is also
situated in close proximity to an area of low pressure and
well-defined frontal zone.

The low-level jet should tend to veer a bit more over the next
several hours, but should maintain a rather strong warm air
advection regime which coupled with the pool of instability should
favor a sustainable and well-organized axis of convection.

PWs are generally near or above 1.75 inches, and this coupled with
the instability should favor rainfall rates capable of reaching 2
inches/hour. The latest hires model guidance including the early
morning WoFS and HRRR solutions suggest downstream rainfall totals
along the path of the MCS reaching 2 to 4 inches. The 90th
percentile of the WoFS suggest some spotty 5 inch totals will be
possible.

These additional rains will be capable of yielding at least an
isolated threat for flash flooding over the next several hours
with the more urbanized locations at greatest risk for impacts.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-YkmdYBnF0dnXjaGbehXK8JPZ5LUh0QAPE2ig2Z_w4HKWciyUfU7OZKYIv_MYYGKF_rR= sjMlfZDHKGYTDBaT3cUPXWc$ for graphic product...

ATTN...WFO...ABR...ARX...DLH...FGF...FSD...GRB...MKX...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 46579428 46419158 45738887 44488841 43568901=20
43319043 43599255 43999448 44369655 45399735=20
46379655=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 161703
FFGMPD
SCZ000-FLZ000-GAZ000-162300-

Mesoscale Precipitation Discussion 0945
NWS Weather Prediction Center College Park MD
102 PM EDT Sat Aug 16 2025

Areas affected...Southern SC...Eastern GA...Northeast FL

Concerning...Heavy rainfall...Flash flooding possible

Valid 161702Z - 162300Z

SUMMARY...A gradual increase in showers and thunderstorms can be
expected through this afternoon. Slow cell-motions and high
rainfall rates will pose a threat for isolated areas of flash
flooding, with the more urbanized areas at greatest risk for
impacts.

DISCUSSION...The midday GOES-E visible satellite imagery shows a
small band of showers and thunderstorms settling south across
southern SC which is allowing for an outflow boundary to gradually
approach the SC/GA border. This convection is generally being
driven by nearby proximity of some weak vort energy. Meanwhile,
some subtle sea breeze convergence along the coast from SC down
through eastern GA is also helping to initiate a few areas of
slow-moving convection.

Over the next few hours, strong diurnal heating within a very
moist environment should aid the development and expansion of
clusters of heavy showers and thunderstorms. Already there are
MLCAPE values of 2000 to 3000 J/kg from the SC Lowcountry down
through northeast FL, and with multiple mesoscale boundary
interactions expected this afternoon, there should be some locally
concentrated areas of convection with high rainfall rates.

Some rainfall rates of 2 to 3 inches/hour will be possible with
the stronger storms. The activity should generally be pulse in
nature given the lack of deeper layer shear, but there will be
slow cell-motions and potential for cell-mergers that foster some
rainfall totals of as much as 3 to 5 inches. This is consistent
with a consensus of the recent HRRR solutions along with the
latest HREF and REFS guidance.

Some isolated areas of flash flooding will be possible through the
afternoon hours, and especially with some of the more urbanized
locations.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9bD8WYUrFX6s_kMlV8hKPqIC3b138GgMmM9j06oLNFFz-jmLR80Oe7VKjEubTq_vDFAM= mjCheKRII0QWKztz_nm8cmE$ for graphic product...

ATTN...WFO...CAE...CHS...FFC...GSP...JAX...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 34068205 33658158 33278078 33247985 32727960=20
32288026 31658086 30678124 29458148 29348207=20
30028289 31618344 33378305=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 162200
FFGMPD
INZ000-WIZ000-ILZ000-IAZ000-170300-

Mesoscale Precipitation Discussion 0946
NWS Weather Prediction Center College Park MD
559 PM EDT Sat Aug 16 2025

Areas affected...southern WI and north-central IL, as well as
surrounding portions of IA/IN

Concerning...Heavy rainfall...Flash flooding likely

Valid 162155Z - 170300Z

Summary...Very heavy downpours with 1-3" short-term rainfall
totals likely to result in isolated to scattered flash flooding.

Discussion...A compact and potent mid-level shortwave trough is
translating rapidly east-southeast over the Upper Midwest this
afternoon, driving a classic series of mesoscale convective
systems (MCSs) along the northern periphery of a blocked synoptic
scale ridge (centered due south over the Midsouth region).
Persistent convection has favored the ML CAPE gradient (500-4000
J/kg) over the past several hours, which has shifted southward
coincident with prior MCS outflow and the associated tightening
surface thetaE gradient. While some convection is still ongoing
from the earlier morning MCS into northeast IL (rapidly
approaching the Chicago metro with MRMS indicating very heavy
downpours with 15-min rainfall totals nearing 1.0"), a trailing
MCS (currently rapidly progressing through southern WI) is quickly
becoming the more dominate expansive MCS. The mesoscale
environment in the vicinity of theses MCSs is otherwise
characterized by anomalously high tropospheric moisture content
(PWs 1.6-2.0", at or above the 90th percentile per GRB/DVN
sounding climatology), and effective bulk shear of 25-50 kts.

While hi-res CAMs have certainly struggled with the precise
convective evolution that has occured (rather typical in these
highly dynamic, progressive MCS events), collectively analyzed
through the HREF (and associated post-processing including
time-lagged members) a valuable forward-looking signal for heavy
rainfall still emerges. The 18z HREF local probability-match mean
(LPMM) QPF suggests a period of localized 2-3"/3-hr associated
with backbuilding along the west/southwest flank of the MCS (with
new convective initiation occurring where low-level inflow and
iscentropic lift coincide with the highest instability). While the
HREF signal is likely too late/slow overall (as this is already
beginning to occur into southwest WI), 40-km neighborhood
exceedance probabilities for 2" exceedance range from 20-50%
(confined to southern WI, though in reality lower-end
probabilities for these amounts likely extend both upstream and
downstream of the dominate MCS, due to underestimated forward
propagation AND backbuilding by the CAMs overall). Although hourly
runs of the HRRR have not proven as useful as the HREF signal
(which also seems rather typical when the environment of the model initialization is mismatched with the observational assimilation),
the experimental WoFS does suggest that similar 2"+ localized
totals are possible (via an increasing trend in the 90th
percentile QPF with a 27-km neighborhood 2" exceedance probs in
the 20-40% range, notably displaced south and west of the HREF
signal).

While the greatest signal/risk for flash flooding is judged to be
across southern WI and northern IL, the MPD also encompasses areas
downstream (southeast into far northwest IN) and upstream (west
into adjacent portions of IA) due to the aforementioned forward
propagation and backbuilding threats. While these surrounding
areas are less likely to realize localized 2"+ totals, the chances
for 1"+ amounts (in as little as 15-30 min with very heavy
downpours) are likely (per HREF/WoFS exceedance probs of 40%+)
with associated 1-hr Flash Flood Guidance (FFGs) ranging from as
low as 1.0-1.5" across a substantial portion of the region. As a
result, isolated to scattered instances of flash flooding are
considered likely (with conditional backbuilding of convection
largely dictating the overall coverage and potential for an
instance or two of more significant flash flooding).

Churchill

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!85RfJsxpSa7tuBurkDXC0aMjTJ4xX4BGbQjCHnUmnpeHIkFvJK0rzeISwXDJQFMobfZF= OoSfOBvy97Tpn6fDKz9qf-I$ for graphic product...

ATTN...WFO...ARX...DVN...ILX...IND...IWX...LOT...MKX...

ATTN...RFC...MSR...TIR...NWC...

LAT...LON 43608890 43418789 42988769 42268726 41618674=20
40868651 40208687 39998789 40058882 40418974=20
40979028 41619055 42079078 42649143 42989143=20
43249113 43369075 43408979=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 170334
FFGMPD
WIZ000-ILZ000-MNZ000-IAZ000-170900-

Mesoscale Precipitation Discussion 0947
NWS Weather Prediction Center College Park MD
1134 PM EDT Sat Aug 16 2025

Areas affected...Southeast MN...Northeast IA...Southern
WI...Northern IL...

Concerning...Heavy rainfall...Flash flooding likely

Valid 170335Z - 170900Z

SUMMARY...Warm-advection thunderstorms with potential for training
and spots of 2-4" across areas of recent heavy rainfall/saturated
soils likely resulting in scattered incidents of flash flooding.

DISCUSSION...GOES-E WV suite shows increased anticyclonic
curvature in upper-level cirrus pattern indicative of shortwave
ridging in the wake of the exiting shortwave across the Lower
Peninsula of Michigan. The associated surface front extends
through central Lake Michigan across southern WI into the northern
row of counties in IA; though the effective boundary due to strong
overturning from this evening's convection intersects the front
near near KPDC and angles southeastward across NE IL into just
north of KDNV. Deep layer moisture remains pooled along the
frontal zone with 1.75-2" Total Pwats across N IA/S MN before
broadening across S WI into northeast IL. LLJ response is a broad southwesterly 15-20kt flow along the entire front; so best
moisture convergence/isentropic ascent is at the intersection
remains along the intersection of the old outflow boundary and
surface front in NE IA/SW WI/NW IL. Upper-level right entrance to
the jet further enhances vertical ascent in proximity to the
front, also helping to sharpen the isentropes vertically
throughout the night. Efficient rainfall production given strong
convergence and unstable air with favorable evacuation aloft,
should support 1.5-2"/hr rates within the expanding cores.=20


GOES-E 10.3um shows strong cooling tops below -65C along the
orthogonal section of ascent, with upstream redevelopment and
increasing TCu noted across SE MN. With flanking development and
steering flow from NW to SE, a favorable training environment
setup may allow for increased duration and localized 2-4" totals
are likely especially from SE MN and SW WI, as potential for
further upstream development is likely throughout the overnight
period as well, and as such an isolated spot over 5" is not out of
the realm of possibility.=20

To compound issues, the area has seen recent heavy rainfall and
the upper soil conditions remain relatively saturated with 0-40cm
ratios well over 50 with spots near 70% across MN, WI (above 90th
percentile) before reducing to below 40% over Chicagoland into NW
IND per NASA SPoRT LIS product(though tonight's rain, likely
improved those values. As such, infiltation may be a bit more
difficult and increased runoff is likely to result in scattered
incidents of flash flooding overnight tonight.=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4XD5kfk4Uj5z4YB_V5dUsJJ-ohvachmPL8OrbNcd2VWkaq4KXlEBEZC03tNWaNyt83pI= qJgYtt6d7ZR79bcGiDWcutM$ for graphic product...

ATTN...WFO...ARX...DVN...LOT...MKX...

ATTN...RFC...MSR...NWC...

LAT...LON 44199254 44149159 43789046 43278856 42758764=20
41828746 41288783 41278892 41989046 42729175=20
43359272 43649301 44039293=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 170532
FFGMPD
SDZ000-NDZ000-171100-

Mesoscale Precipitation Discussion 0948
NWS Weather Prediction Center College Park MD
132 AM EDT Sun Aug 17 2025

Areas affected...Northwest South Dakota...South-central North
Dakota...

Concerning...Heavy rainfall...Flash flooding possible

Valid 170530Z - 171100Z

SUMMARY...Expanding convective clusters with potential
repeating/merging elements. Rates of 1.75-2"/hr and localized
2-3" totals pose localized possible incidents of flash flooding
overnight.

DISCUSSION...GOES-E WV suite shows an elongated north to south
shortwave feature along the eastern edge of larger scale trough in
the Northern Rockies, lifting northeastward out of northwest SD
into southwest ND continuing to be enhanced by broad right
entrance of 300mb 50kt jet entrance along its northwest quadrant.
This is supporting a strong surface to low level wind response,
further confluent/convergent along and north of the Black Hills
across W SD. 05z surface analysis shows stationary front along
the SD/NEB border with Tds in the low to upper 70s throughout the
SD fluxed on solid, weakly confluent easterly flow. The bulk of
the moisture resides north of the surface front, though 850-700mb
moisture flux convergence is further increased deep layer flux
given directional confluence from southerly to southeasterly along
the southern flank of the elongated shortwave trough north of the
Black Hills. As such, Total PWat values have increased from 1.75
along the convergence axis. As such, strong clusters continue to
expand and merge with pre-cursory convergence axes across
northwest SD; noted in the RADAR mosaic and expanding/cooling
10.3um IR canopy tops. Ample mid-level lapse rates and higher
theta-E air support CAPEs over 2000 J/kg which further increase
within the upstream inflow region north of the frontal zone. As
such, cells are already becoming rather efficient in rainfall
production with rates of 1.75-2"/hr noted throughout the expanding clusters.=20=20

As the trough is lifting, differential shear within the steering
profile (as the elongated trough lifts north) is helping to orient
cell motions toward a repeating/short-term training profile, which
is expected to become further convergent as the wave is reaching
the apex of the synoptic ridging over south-central ND. As a
result, an axis of 2-3"+ totals are likely to expand toward a
larger cluster toward the central common border of the Dakotas
over the next 3-5hrs. The rates alone are near/just above the
1-1.75"/hr FFG values in all but a few scattered locations within
the area of concern and localized areas are probable to exceed the
2-2.5"/3hr values, suggesting flash flooding is possible through
the overnight period. And while the top layers have been in
prolonged drought with 0-40cm saturation ratio below 25%, the
sheer rate on hard soils will further limit infiltration and
result in increased runoff.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9A1tL6ALpcWkq0Q1jTWNfI1ulZQ3PVJDOTEd9YVG12RiO_Knvvl5ztfrimIZYxeLqCwP= DZ3lb1GNFPxlCSsBYCu2rCQ$ for graphic product...

ATTN...WFO...ABR...BIS...UNR...

ATTN...RFC...KRF...NWC...

LAT...LON 46850021 46699900 46299858 45569891 45059981=20
44620088 44070304 44470377 45150381 45670352=20
46030294 46550185=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 170603
FFGMPD
MNZ000-SDZ000-171200-

Mesoscale Precipitation Discussion 0949
NWS Weather Prediction Center College Park MD
203 AM EDT Sun Aug 17 2025

Areas affected...Southern Minnesota...East-central South Dakota...

Concerning...Heavy rainfall...Flash flooding possible

Valid 170600Z - 171200Z

SUMMARY...Slow moving, potentially repeating cells pose 2-4"
totals and possible localized incidents of flash flooding through
the remainder of the overnight period.

DISCUSSION...GOES-E 10.3um IR loop shows expanding cluster of
thunderstorms across SW MN over the last few hours and starting to
become better organized with broadening up/downdrafts;
concurrently while newer development is developing between it and
the downstream clusters in WI/MN/IA Tri-state area. Additionally,
combined with 3.9um loop, low stratus north of the frontal
boundary across central MN/N WI shows southward cold advection
that is further steepening the isentropes across the frontal
boundary that generally sits across the northern row of counties
in Iowa. RAP analysis, confirmed by CIRA LPW shows pool of deep
layer moisture with Total PWat values over 2" extending from
northeast SD through SE MN, generally enhanced further west where
flux has been greatest along the nose of the southerly low-level
jet where winds are up to 20-25kt per KFSD VWP vs 15-20kts further
east. The strong moisture convergence along the steepening
isentropic surface, MLCAPEs of 3000-3500 J/kg, has resulted in a
slightly southward development versus 00z Hi-Res CAMs and recent
HRRR cycles, as such, proximity to stronger orthogonal moisture
flux should support efficient rainfall production with rates of
2"/hr.

Stronger shortwave to the west and exiting one to the east has
resulted in fairly unidirectional but also weaker steering flow
just a bit south of due east and parallel to the frontal boundary.
Mean winds of 10-15kts are expected and should allow for some
potential training, but more likely slow overall cell motion
allowing for a few hours of intense rainfall and pockets of 2-4"
totals. Stronger LLJ due to the approaching wave over the western
Dakotas suggest upstream convective development is probable later
into the overnight periods far west as the Coteau des Prairies
Plateau, but also intersect with back-building from upstream
cluster/WAA cells in SE MN. As such, have included portions of SE
MN that were incorporated in MPD 947 for longer valid time toward
12z.=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7STG0ZQBcR9jgl17njBbuRM45-xzCK3rQdwkyNG1TqkTolDpUFzKmxTd_1U_fV3ahuRZ= TOVzwQGN6EDSj8LTIAH8J7s$ for graphic product...

ATTN...WFO...ABR...ARX...FSD...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 45469700 45419560 45269458 44899338 44499251=20
44019168 43729146 43539186 43579398 43759520=20
44159650 44619756 44979777 45339764=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 170830
FFGMPD
INZ000-ILZ000-171300-

Mesoscale Precipitation Discussion 0950
NWS Weather Prediction Center College Park MD
429 AM EDT Sun Aug 17 2025

Areas affected...Northeast Illinois...Northwest Indiana...

Concerning...Heavy rainfall...Flash flooding possible

Valid 170830Z - 171300Z

SUMMARY...Isentropic ascent within remaining unstable/moist
environment continues. Additional 1.5-3" totals training in
proximity of Chicago and suburbs will keep risk of incidents of
flash flooding possible through daybreak.

DISCUSSION...GOES-E 10.3um IR loop shows much of northern IL has
remained untapped through the overnight period. This is confirmed
by recent RAP analysis fields with 2500-3000 J/kg of MUCAPE across
N IL. Surface analysis continue to show affects of initial
evening complex of return southeasterly flow with remnants of a
boundary angled NW to SE from far NW IL toward DNV, which given
recent elevated convective lines through Chicagoland; seems to be
reinforced with steepened isentropes from north to south. This
while VWP at DVN and LOT/ORD shows generally west and
west-northwest 15-25kts orthogonal to the boundary. RADAR shows a
few upstream cells redeveloping given the stronger moisture flux
in the upglide through N IL. Moisture remains more than ample
given Tds in the low to mid 70s from the source while mid-level
moisture/RH remains solid for a core of 2"+ total PWats through
the ascent plane. As such, thunderstorms will have solid vertical
moisture loading to continue to support 2"/hr rates.

Deep layer steering starts to curl anti-cylonically along the
northeast edge of the deeper ridging, and convection has been
bending right of mean flow becoming parallel to the IND/IL border.
Though further southward, the inflow/upglide weakens and becomes
displaced from the core of unstable air, so cells have been
generally weakening further south or eastward, and this is likely
to continue throughout the early morning, limiting the risk for
additional heavy rainfall toward northeast IL/Northwest IND.=20

Currently LLJ strength is strong and with heavy rainfall/cold pool
generation closer to the Lakeshore, westward propagation and
closer to surface rooting of cells may limit path of newer
development to train over earlier tracks, but there will remain
some intersection for an additional 1-3" with newer cells; combine
that with proximity to urban environment near Chicago and
increased run-off make it more probable that incidents of flash
flooding/rapid inundation remain possible through the early
morning hours.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5xAMj4-01uIHivdK-1pSE1hmvhDQfj2cxMRA2KrmTQ_coF3ArZdVaoWhH8TCLPPffO3V= ItuQiImU_QGYmK5y4pYxYFM$ for graphic product...

ATTN...WFO...ILX...IND...IWX...LOT...

ATTN...RFC...MSR...TIR...NWC...

LAT...LON 42418859 42148785 41108660 40248662 40088755=20
40518816 41288894 42248930=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 171201
FFGMPD
MNZ000-IAZ000-SDZ000-NDZ000-171700-

Mesoscale Precipitation Discussion 0951
NWS Weather Prediction Center College Park MD
800 AM EDT Sun Aug 17 2025

Areas affected...Northeast SD...Southeast ND...West-Central to
Southern MN...Far Northern IA

Concerning...Heavy rainfall...Flash flooding likely

Valid 171200Z - 171700Z

SUMMARY...Additional heavy showers and thunderstorms this morning
will continue to foster areas of flash flooding.

DISCUSSION...The early-morning GOES-E IR satellite imagery along
with radar shows a fairly organized axis of locally training
showers and thunderstorms impacting southern MN. This convection
is focused generally along and just north of a stationary front
draped west to east across the Upper Midwest.

MUCAPE values of 2000+ J/kg remain in place along this boundary
which in conjunction with a relatively modest southwest 20 to 30
kt low-level jet interacting with it should favor renewed rounds
of heavy showers and thunderstorms. This activity will continue to
be capable of training over the same area going through at least
the mid to late-morning hours given alignment that is nearly
parallel to the deeper layer steering flow. Some southward advance
of this activity into far northern IA is also possible given the
influence of the convectively enhanced cold pool close to the
MN/IA border.

Additional areas of heavy showers and thunderstorms will also be a
concern upstream over parts of northeast SD and southeast ND as an
upstream forward propagating MCS arrives and interacts with the
aforementioned front while fostering somewhat stronger warm air
advection out ahead of it. However, this activity at least by late
this morning should begin to gradually weaken as it approaches
west-central MN.

Rainfall rates with all of the stronger and more organized cells
in the short-term will still be capable of reaching 1.5 to 2.5
inches/hour which is being supported by the instability and a
corridor of 1.75+ inch PWs.

Additional rainfall totals as high as 3 to 5 inches will be
possible, and especially over southern MN where some of the most
organized convective activity is occurring. The latest HRRR and
WoFS guidance supports these totals at least locally as well.

Given the ongoing areas of flash flooding locally, and with these
additional rains, more areas of flash flooding are expected going
through at least the mid to late morning hours.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!56TkRIQJK3ffzR8f1-r4_AVzE_ZpkgcinyTZePlWrZA1-epLQBqWltwsEUBJp8obdAXO= MBjDkXa8k1b8ajG3HF30ygE$ for graphic product...

ATTN...WFO...ABR...ARX...BIS...DMX...FGF...FSD...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 47399736 47029653 45619526 44849413 44129220=20
43509139 42869167 42889342 43409578 44189741=20
45169862 46319889 47179848=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 180145
FFGMPD
WIZ000-ILZ000-MNZ000-IAZ000-180600-

Mesoscale Precipitation Discussion 0952
NWS Weather Prediction Center College Park MD
944 PM EDT Sun Aug 17 2025

Areas affected...south-central/southeastern MN into
north-central/northeastern IA and adjacent portions of WI/IL

Concerning...Heavy rainfall...Flash flooding likely

Valid 180140Z - 180600Z

Summary...1-3"/hr rainfall rates to continue into the overnight,
resulting in localized short-term rainfall totals as high as 4-8".
Scattered to numerous instances of flash flooding likely, some
significant/life threatening (particularly across south-central
and southeastern MN).

Discussion...Convection is proliferating this evening in the
vicinity of a low-level frontal zone and associated
instability/thetaE gradient, extending from southwestern MN
through northeastern IA into northern IL. A weak shortwave/vort
max immediately upstream (ND/SD/MN border region) seems to be
resulting in the most intense/widespread convection across
south-central MN into north-central IA (by way of DPVA and added
divergence aloft from the right-entrance region of an associated
jet streak), and this convective organization should continue into
the early overnight hours as the low-level jet strengthens. The
mesoscale environment is otherwise characterized by an MLCAPE
gradient of 2500-4500 J/kg (with +400 J/kg in the past 3-hr over
southern MN), precipitable water of 1.6-2.0" (well above the 90th
percentile and approaching the max moving average, per MPX
sounding climatology), and effective bulk shear of 25-30 kts.

While observational trends favor portions of south-central and
southeastern MN for the greatest coverage and intensity of heavy
rainfall in the near term, the hi-res CAMs (18z HREF and 12z
experimental REFS) strongest signal is displaced to the northwest
(clustered over central MN, which is where the best dynamics are=20
certainly located... but ultimately too far displaced from the
best boundary layer thermodynamics which the deep convection has
favored and anchored to). Despite this spatial displacement, the
signal suggests relatively high chances for localized 3"
exceedance (30-50% probs, per 40-km neighborhood of HREF/REFS).
Farther to the southeast along the frontal zone (where dynamics
are less impressive and training should be less of an issue, but
storm motions tend to be slower with storms still capable of
1-3"/hr rates) the CAMs still support the potential for 3"
exceedance (10-30% probs) with the more recent experimental WoFS
runs (23-01z) even suggesting the potential for localized totals
of 4-8" from south-central/southeastern MN into
northeastern/eastern IA (per 90th percentile QPF and associated 5"
exceedance probabilities of 40%+).

As much of the region remains fairly saturated from recent days
heavy rains (with an axis of 2-4" of rain across a portion of the
area over just the past 24-hr), Flash Flood Guidance (FFG) suggest
impacts from as little as 1.0-2.0" over 1-3 hour period. As a
result, scattered to numerous instances of flash flooding are
considered likely. Given the particular hydrologic sensitivity
across portions of southeastern MN (including the Twin Cities
metro area), there is a higher than typical risk for localized
instances of significant/life threatening flash flooding.

Churchill

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!76xaIs_f8fQ7BJ6EZvJ_qHK0uQiB3EF9kShSl3fQ7NBybjMyuGPDUNX5c-IH4NBJpSeE= R524hl5QYgDAH8jb2hGIVHw$ for graphic product...

ATTN...WFO...ARX...DMX...DVN...FSD...ILX...LOT...MKX...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 45599402 45539299 44939193 44209097 43499030=20
42648973 40878869 40488968 41449141 41969241=20
42659378 43249509 44269503 45059471=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 180558
FFGMPD
WIZ000-MNZ000-IAZ000-NEZ000-SDZ000-181200-

Mesoscale Precipitation Discussion 0953
NWS Weather Prediction Center College Park MD
157 AM EDT Mon Aug 18 2025

Areas affected...Southeast SD...Northeast NEB...Northern
IA...Southern MN...Western WI...

Concerning...Heavy rainfall...Flash flooding possible

Valid 180600Z - 181200Z

SUMMARY...A muddled mess of shortwave, warm advection and
small/storm scale forcing within a solidly unstable/deep moist
environment should result in widely scattered thunderstorms with
some weakly organized clusters capable of short-duration training
elements. Widely scattered incidents of flash flooding remain
possible through late overnight period

DISCUSSION...Regional RADAR mosaic denotes two weakly organized
shortwave features. The leading one having driven stronger
thunderstorms and scattered flash flooding is progressing out of
southeast MN into NW WI with the convergent banding noted from
north-central IA through to the eastern quadrant of the shortwave
into west-central WI. The second flatter west to east wave across
southern SD is driving some smaller clusters with weakening bowing
elements and trailing convergent thunderstorms in the eastern Sand
Hills of NEB.

Both reside in a broad southerly low level jet providing some
moisture flux and isentropic ascent/convergence along stationary
front that extends from east of KPIR to south of KFSD and through
northern IA before angling southeastward from a weak surface
inflection west of KALO southward into IL near KGBG. Surface Tds
remain well above average ranging through the 70s with spots of
75-77F pooled along it. This results in 1.9 to 2.1" total Pwats
along its length; though stronger LLJ to 25-30kts west of the
Missouri River is increasing moisture ahead of the western,
upstream wave. Environment remains fairly unstable with ample
well of 2000-3000 J/kg of MUCAPE for any areas of forcing focused
enough to break through minimal capping with isentropic
ascent/convergence along the front. Instability pool is a bit
deeper and extends northward through the isentropic ascent further
west with the stronger LLJ. Here rates are likely to be stronger
up to 2"/hr but forward propagation may limit overall duration.=20
Deep layer westerly flow aloft may also allow for some
short-duration training/repeating across NE NEB/SE SD into NW IA;
which will likely be necessary for localized totals over 3" in
3-4hrs. These higher rates/totals will be more necessary across
an area with higher FFG due to recent very dry conditions. Still
widely scattered incidents remain possible.

Further east across SE MN/NE IA/W WI...A wedge of
enhanced/confluent flow due to exiting shortwave in MN will allow
a narrow channel along its southern and eastern flank for
additional elevated convection that has some potential for training/back-building. As the instability reduces quicker toward
the northeast into central WI, the coverage and intensity will
diminish quickly and likely not exceed the FFG into Northern and
northeastern WI. However, continued upglide/back-building through
lower FFG due to recent heavy rainfall across southern MN/SE MN
and northern IA may see spots of 2-3" and similarly possible
incidents of scattered flash flooding through 12z.

Overall, confidence is below average for any given location for
flash flooding given above average dispersion of Hi-Res CAM
solutions to the evolution. Still, the environment remains
solidly conducive that a few incidents of localized flash flooding
are probable, especially over the recently saturated regions north
and east of the surface front. Scattered 2-3" totals with
isolated 4" totals remain possible through 12z.=20=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7P_gzk4TUTDVORWHTYeu_xM8uURX-V4bitHuGtd71LNKDGt8-zAnhoIhlIJ_tDcuTcUH= XgOPBCxy2q0rPI5XrEvetws$ for graphic product...

ATTN...WFO...ARX...DMX...FSD...MPX...OAX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON 45309238 44819084 43989037 43229057 42659215=20
41989427 41269594 41299670 41929730 42359761=20
42869792 43839826 44579601 45269474=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 181838
FFGMPD
MDZ000-VAZ000-NCZ000-SCZ000-190000-

Mesoscale Precipitation Discussion 0955
NWS Weather Prediction Center College Park MD
237 PM EDT Mon Aug 18 2025

Areas affected...Coastal Plain from Southeast Virginia through
Northeast South Carolina

Concerning...Heavy rainfall...Flash flooding possible

Valid 181836Z - 190000Z

Summary...Showers and thunderstorms developing along a cold front
will expand and intensify through the afternoon. These storms will
be slow moving, and contain rainfall rates of 1-3"/hr. This could
produce 2-3" of rainfall with locally higher amounts, and
instances of flash flooding.

Discussion...The GOES-E day-cloud phase microphysics RGB this
afternoon is beginning to show rapid updraft growth from the
Tidewater region of Virginia through eastern NC. These storms are
developing along a slowly advancing cold front, with low-level
convergence along the boundary the primary ascent mechanism. Lift
along this front is occurring into robust thermodynamics to
support heavy rainfall. PWs measured by GPS are as high as 1.6
inches in southeast Virginia, and onshore northeast flow is
funneling a narrow corridor of PWs above 1.9 inches into eastern
NC. This elevated PW is overlapping MUCAPE of 2000-3000 J/kg
centered along this front, and developing convection within this
environment is producing radar-estimated rain rates that have
already exceeded 1.5"/hr according to KMHX.

The high-res CAMs are a little slow to capture the ongoing
development, but are generally in agreement that a narrow corridor
of thunderstorms will expand along this front through peak heating
of the aftn. This is reflected by relatively high EAS
probabilities for 1"/6hrs focused across eastern NC which reflect
the good CAM agreement. These storms will be generally slow moving
from N/NE to S/SW along the boundary, and cell motions progged by
propagation vectors the next several hours will be just around 5
kts. Additionally, these propagation vectors will remain aligned
to the front, suggesting training and repeating cells through the
aftn. With rain rates likely reaching 1-3"/hr (HREF neighborhood
probabilities for 2"/hr peaking above 60% coincident with HRRR
15-min rainfall above 0.75" suggesting brief 3"/hr rates), total
rainfall could reach 2-3" with locally as much as 5" possible as
shown by HREF neighborhood probabilities for 5"/6hrs as high as
20%.

This region has been quite wet recently as reflected by AHPS 7-day
rainfall that is above 300% of normal in most of the discussion
area. Although some of this rainfall has drained efficiently to
lower 0-10cm RSM to less than 50% and elevate 3-hr FFG to above
3", the forecast slow movement and training of these cells is
still causing HREF 3-hr FFG exceedance probabilities above 40%.
While this suggests the flash flood risk is generally confined to
where the most significant training can occur, it is possible that
any of these intense rain rates, especially if they occur atop an
urban area, could cause instances of flash flooding through the
aftn.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4I_e7VsRrKjX02qlF4k1XwL2QAT_xzlhXmOSA6OKnhEchwSbzt2AJDbrybOK6T94vTxU= NgzMyL-ZwtGJzDgtJFSu7So$ for graphic product...

ATTN...WFO...AKQ...CAE...ILM...MHX...RAH...

ATTN...RFC...ALR...RHA...NWC...

LAT...LON 38027567 37737546 37347537 36607542 36067548=20
35467578 34927611 34637662 34427735 34257805=20
34137857 33977928 33897995 33938042 34098063=20
34338052 34637978 34897904 35457818 36247740=20
36977686 37587637 37897615=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 182150
FFGMPD
MIZ000-INZ000-WIZ000-ILZ000-MNZ000-IAZ000-190300-

Mesoscale Precipitation Discussion 0956
NWS Weather Prediction Center College Park MD
548 PM EDT Mon Aug 18 2025

Areas affected...eastern IA, southern WI, and northern IL into
surrounding portions of MN/IN

Concerning...Heavy rainfall...Flash flooding likely

Valid 182145Z - 190300Z

Summary...Thunderstorms with hourly totals of up to 1-2" are
expected to train/repeat with short-term totals of 2-5". Scattered
to numerous instances of flash flooding are likely (and locally significant/life threatening flash flood concerns are particularly
elevated in the vicinity of the Chicago metro).

Discussion...Convection is proliferating once again today across
portions of the Upper Midwest, focused primarily in the vicinity
of a weak surface low pressure and an associated warm front. The
mesoscale environment very supportive of heavy rainfall with
plentiful instability (1500-5500 J/kg of SBCAPE), highly anomalous
tropospheric moisture (PWs 1.7-2.0", between the 90th percentile
and max moving average, per DVN sounding climatology), and
effective bulk shear of 20-40 kts (with the best shear farther
north along the warm front, and generally below 20 kts farther
south into the warm sector (southeast IA into north-central IL). A
shortwave and associated vorticity maxima aloft (located nearly
directly above the weak surface low @ 500 mb) will provide
additional forcing for lift, along with a bit of additional
divergence from an associated right-entrance region of a jet
streak (though the best upper-level divergence is displaced to the
northeast into northern WI/MI, where instability is much more
limited). As the low-level jet strengthens into the evening hours,
this should help to sustain updrafts and organize convection
(despite only conditionally unstable mid-level lapse rates) with a
series of linear segments of thunderstorms resulting in localized
west-to-east training (despite relatively strong steering flow
with 850-300 mb winds of 20 kts). With MRMS already indicating
localized hourly totals as high as 1-2" with 3-hr Flash Flood
Guidance (FFG) generally ranging from 1.0-2.0" across the MPD
area.

As the strongest convection (with hourly estimates as high as 2")
approaches the greater Chicago metro area, the risk for instances
of life threatening flash flooding are elevated late this
afternoon and evening. Nearly all of the latest hi-res CAM data
supports these significant flash flooding concerns, as the 18z
NAM-nest and hourly runs of both the HRRR and experimental RRFS
since then depict localized totals of 3-5" in the vicinity of the
Chicago metro (with the NAM-nest and some RRFS runs indicating the
potential for extreme localized totals of 5"+, which is also
reflected in the 18z HREF neighborhood probabilities of 5"
exceedance ranging from 10-20%). While southeast WI into northeast
IL is certainly the greatest area of concern for prolong/repeated
heavy rainfall, areas farther south and west are still likely to
flood from expected 2-4" localized totals (given aforementioned
FFGs of only 1.0-2.0" for much of the area). As a result,
scattered to numerous instances of flash flooding are likely.

Churchill

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4MgnU1l7BBX0TE4tOcovvaLLc6qbPJbd9pwnHqFao_DUJt5zvmxmVPeuEKeRgbQfWojn= oiIAT6WbW2gP8WSBEDbbGS4$ for graphic product...

ATTN...WFO...ARX...DMX...DVN...ILX...IWX...LOT...MKX...

ATTN...RFC...MSR...TIR...NWC...

LAT...LON 44239208 44019148 43569066 43198951 43098863=20
43098782 42518752 42038714 41728636 41038677=20
40638724 40488814 40548896 40839010 40749126=20
40979179 41359214 42859191 43049262 43369245=20
43619248 43779265 43999272 44149246=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 190241
FFGMPD
MIZ000-INZ000-WIZ000-ILZ000-190845-

Mesoscale Precipitation Discussion 0957
NWS Weather Prediction Center College Park MD
1040 PM EDT Mon Aug 18 2025

Areas affected...Southern WI...Northern half of IL...Northwest
IND...Far Southwest LP of MI...

Concerning...Heavy rainfall...Flash flooding likely

Valid 190245Z - 190845Z

SUMMARY...Incidents of flash flooding likely to continue, yet
overall coverage/totals will reduce with increasing forward speed.
Best chance for flash flooding will be new 'repeated' cell tracks
across S WI/NE IL

DISCUSSION...GOES-E WV, RADAR and RAP analysis show southern
stream, convectively enhanced shortwave/MCV feature is pressing
eastward across Chicago into southern Lake Michigan at this time,
continuing to drive strongest downstream low level convergence
along the quasi-bowing feature from northwest IND southward across
the Kankakee Valley. Storms remain in unstable environment with
ample deep layer moisture (Tds in the mid 70s and total moisture
over 2"), but the stationary front remains anchored across
southwest LP of MI into north-central IND before Tds and unstable
air rapidly srop off, so there is a narrow area of enhanced
rainfall rates up to 2", but cells should quickly diminish into
the more stable air. Additionally, area across LP of MI and
Northeast IND has been much drier and FFGs reflect that, further
reducing the risk to all but the most ideal training across
urban/low infiltration ground conditions.

However, the upstream flanking line across into central IL, does
remain very unstable with MUCAPEs of 2000-3000 j/kg and solid
moisture flux convergence along the confluent low level flow
regime. Deep layer steering may allow for some southwest to
northeast repeating, though height-falls from the passing
shortwave/MCV should allow for southeast propagation to limit
overall totals to 2-3", lower FFG values of less than 2"/hr and
1.5-2.5"/3hrs in all but the further southwest portions of central
IL remain at good risk of locally being exceeded through the next
few hours.

Further north...S WI/N IL...
GOES-E WV depicts core of larger/synoptic to mesoscale shortwave
feature across central to S WI, is exiting and downward mixing is
starting to help advance the stationary front across SW WI through
depth, sharpening convergence along and south of the boundary.=20
While partially mixed, there remains ample remaining unstable air
of 1500-2000 J/kg and ample deep layer moisture to support an
additional round of stronger thunderstorms. These upstream
thunderstorms will be narrower in nature but should have the
opportunity to track across areas already affected by heavy
rainfall with rates of 1.75-2"/hr; localized additional 1-3"
totals would reaggravate any flooding conditions across S WI and
few northern rows of N IL. As such, localized incidents of flash
flooding are likely to persist through the overnight period.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8FSgKNGQdISKEqfYISW9rhW6hqzxvy4s9MUJ48_k8kXlVGsBMlIfs0Ib2wcDKqU5QdFX= pStbyaxUrQBwe3Rzztnfogs$ for graphic product...

ATTN...WFO...DVN...GRR...ILX...IND...IWX...LOT...MKX...

ATTN...RFC...MSR...TIR...NWC...

LAT...LON 43398673 43118619 42518584 41708587 40518639=20
39988741 39908888 40019006 40469037 40869000=20
41278958 41708930 42168939 42489001 42988980=20
43348839=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 191321
FFGMPD
MDZ000-VAZ000-191918-

Mesoscale Precipitation Discussion 0958
NWS Weather Prediction Center College Park MD
920 AM EDT Tue Aug 19 2025

Areas affected...southeastern Virginia/far southern DelMarVa
Peninsula

Concerning...Heavy rainfall...Flash flooding possible

Valid 191318Z - 191918Z

Summary...A focused areas of nearly stationary convection has
produced spots of 2.5-5 inch rainfall totals across the far
southern DelMarVa Peninsula this morning. Additional totals of
3-5 inches cannot be ruled out. Localized/isolated inundation is
expected through at least 19Z.

Discussion...Slow-moving convection has evolved across the
southern DelMarVa this morning. The storms are embedded within a
relatively focused area of low-level convergence just east of a
weak surface low near PHF/Williamsburg, with low-level easterlies
maintaining moisture/buoyancy against a more stable airmass across
much of Virginia. Weak/modest kinematics were supporting slow
cell movement, and spots of 1-3 inch/hr rain rates were being
estimated per MRMS with the most dominant activity. A few flood
impacts have also been observed near the Accomack, VA area this
morning.

Although the spatial extent of the flash flood threat is fairly
localized, the slow evolution of meso-to-synoptic-scale features
supporting heavy rainfall is a bit concerning. Heavy rainfall
could persist in this regime through 19Z, with additional 3-5 inch
rainfall totals possible. Models suggest that the convergence
axis/low supporting heavy rainfall will gradually migrate westward
through midday, which may temper the heavy rain threat eventually.
Local impacts are expected to continue and may worsen while heavy
rainfall persists.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7CDMLYKzxEq4_Nj_6X8tZAYHCj5Q4MritnzxdHRS-8x4Xwy8ZnclDBERWJuIEqpRzRTM= gHU0BKUZcEtDPLTOyGTbgg0$ for graphic product...

ATTN...WFO...AKQ...

ATTN...RFC...ALR...RHA...NWC...

LAT...LON 38167536 37587545 36727585 37217686 37937655=20
38137597=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 191321
FFGMPD
MDZ000-VAZ000-191918-

Mesoscale Precipitation Discussion 0958
NWS Weather Prediction Center College Park MD
920 AM EDT Tue Aug 19 2025

Areas affected...southeastern Virginia/far southern DelMarVa
Peninsula

Concerning...Heavy rainfall...Flash flooding possible

Valid 191318Z - 191918Z

Summary...A focused areas of nearly stationary convection has
produced spots of 2.5-5 inch rainfall totals across the far
southern DelMarVa Peninsula this morning. Additional totals of
3-5 inches cannot be ruled out. Localized/isolated inundation is
expected through at least 19Z.

Discussion...Slow-moving convection has evolved across the
southern DelMarVa this morning. The storms are embedded within a
relatively focused area of low-level convergence just east of a
weak surface low near PHF/Williamsburg, with low-level easterlies
maintaining moisture/buoyancy against a more stable airmass across
much of Virginia. Weak/modest kinematics were supporting slow
cell movement, and spots of 1-3 inch/hr rain rates were being
estimated per MRMS with the most dominant activity. A few flood
impacts have also been observed near the Accomack, VA area this
morning.

Although the spatial extent of the flash flood threat is fairly
localized, the slow evolution of meso-to-synoptic-scale features
supporting heavy rainfall is a bit concerning. Heavy rainfall
could persist in this regime through 19Z, with additional 3-5 inch
rainfall totals possible. Models suggest that the convergence
axis/low supporting heavy rainfall will gradually migrate westward
through midday, which may temper the heavy rain threat eventually.
Local impacts are expected to continue and may worsen while heavy
rainfall persists.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7jxEu38haEH6mlmWZFGG1sQ5vn7L0IAWaB2c44_hdv1Zoayb99uNoq_IHQLf0WaArZpo= V0fwh_G8cmXkaXLR_8bR86g$ for graphic product...

ATTN...WFO...AKQ...

ATTN...RFC...ALR...RHA...NWC...

LAT...LON 38167536 37587545 36727585 37217686 37937655=20
38137597=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 191733
FFGMPD
TXZ000-NMZ000-AZZ000-192332-

Mesoscale Precipitation Discussion 0959
NWS Weather Prediction Center College Park MD
132 PM EDT Tue Aug 19 2025

Areas affected...eastern Arizona, portions of New Mexico

Concerning...Heavy rainfall...Flash flooding possible

Valid 191732Z - 192332Z

Summary...Thunderstorms will increase in coverage and intensity
through 00Z/6p MDT, with flash flooding possible especially in
low-lying spots and near burn scars.

Discussion...Latest satellite/radar imagery depicts abundant
insolation leading to isolated convective development along
favored ridgelines/terrain - especially in New Mexico. The storms
are forming in an environment with just enough mid-level
instability and moisture (0.75-1.3 inch PW values) for wetting
thunderstorms to develop. Kinematic fields aloft suggest slow and
at times erratic movement with any developing activity. Models
and observations are also suggestive of continued expansion of
convective coverage through peak heating hours and beyond.

As cells continue to expand in coverage, areas of 0.5-1 inch/hr
rain rates will become more common. Perhaps the highest
concentration of higher rain rates will occur across southern New
Mexico and southeastern Arizona where moisture content/PW values
are highest. Areas of heavy rainfall may occur atop sensitive
low-lying areas and burn scars that could enhance runoff locally.

Models (particularly the HREF) depict that the peak convective
threat will likely occur in the 21-00Z timeframe, with slow
weakening expected beyond that timeframe. Flash flooding will be
possible given the aforementioned scenario.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-Het168qicskNAsHlcFvgNT6ffe7kkBl8tiXYh8DP59KVcR8OcKFoZT5BMkyoe9HslIv= i8XSwK8C79k4CxM4xhohGMs$ for graphic product...

ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...

ATTN...RFC...FWR...STR...TUA...NWC...

LAT...LON 36840536 35890489 33770473 32920503 31800612=20
31710819 31370831 31371092 31641155 32631118=20
33940991 34770860 35890735 36760636=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 191825
FFGMPD
NCZ000-SCZ000-GAZ000-TNZ000-ALZ000-200000-

Mesoscale Precipitation Discussion 0960
NWS Weather Prediction Center College Park MD
225 PM EDT Tue Aug 19 2025

Areas affected...Southern Appalachians

Concerning...Heavy rainfall...Flash flooding possible

Valid 191823Z - 200000Z

Summary...Thunderstorms with 2-3"/hr rain rates will expand across
the Southern Appalachians this afternoon. These storms will be
very slow moving, leading to 2-3" of rainfall with locally as much
as 5" possible. Flash flooding may result.

Discussion...The GOES-E day-cloud phase microphysics RGB this aftn
shows a rapid intensification of updrafts now featuring cloud ice
as Cbs develop along a line from west-central NC into far northern
GA. This activity is blossoming in response to persistent upslope
flow on E/NE winds behind a cold front that has sagged into the
GA/SC coastal plain as analyzed by WPC. Despite being behind the
front, this low level flow is pooling moisture across the Southern
Appalachians as reflected by PWs measured by GPS as much as 1.5
inches near Asheville, NC and 2.1 inches near Columbia, SC. At the
same time, breaks in the clouds on the western periphery of the
cold air damming (CAD) is allowing for a rapid increase of
instability which is now analyzed via the SPC RAP to be 2000-3000
J/kg. The fresh convection in northern GA has already resulted in
MRMS hourly rainfall of nearly 1.5 inches and resultant FLASH
response of 300+ cfs/smi unit streamflow.

Although the CAMs differ in the coverage of convection through
this aftn, the persistent upslope flow into this overlap of
moisture and instability should support expansion and continuation
well into the evening. Rainfall rates as progged by the HREF
neighborhood probabilities have a 20-30% chance of exceeding 2"/hr
within any of this convection, while the HRRR 15-min rainfall
indicates up to 0.75" suggesting brief 3"/hr rain rates. Despite
the uncertainty in coverage, the HREF EAS probabilities indicate
the greatest potential for heavy rainfall will be across the Blue
Ridge and southward into the northern GA Piedmont, and this is
supported by the differential heating boundary caused by the cloud
breaks within the CAD to the east. A ridge to the west will keep
overall forcing generally light and flow weak, indicating that
storms will move very slowly on 0-6km mean winds of just 5 kts.
This could be problematic as the continued upslope flow will
support regenerating cells, and at times storms may stall with
zero net motion, especially during periods of boundary
interactions within the otherwise pulse environment.

The slow movement and regenerating behavior of these heavy rain
rates could produce 2-3" of rain, with locally as much as 5"
possible (10-15% chance from the HREF). This heavy rain will occur
across soils that are vulnerable both due to the general
sensitivity of the complex terrain, but also due to 0-10cm soil
moisture that is above the 95th percentile according to NASA
SPoRT. Any heavy slow moving heavy rainfall across this region
could quickly result in runoff and instances of flash flooding.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7N3S-qjnsUCg83J-x0KRtNHFa29zN6Z9J63xmHkCyfCmVqURHlWm0kaxVrUsyedOUhlP= G6_aCnAIEG6CKFucLtd1qRM$ for graphic product...

ATTN...WFO...BMX...FFC...GSP...HUN...MRX...RNK...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 36568158 36118170 35888189 35588221 34888283=20
34168342 33818355 33658367 33518394 33568465=20
33908534 34398560 34968542 35288499 35518446=20
36268260 36438216=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 191826
FFGMPD
MOZ000-KSZ000-192322-

Mesoscale Precipitation Discussion 0961
NWS Weather Prediction Center College Park MD
223 PM EDT Tue Aug 19 2025

Areas affected...portions of central and eastern Kansas

Concerning...Heavy rainfall...Flash flooding possible

Valid 191822Z - 192322Z

Summary...Slow-moving thunderstorms will produce areas of 1-2
inch/hr rain rates through 00Z/7p CDT tonight. Areas of flash
flooding are possible.

Discussion...A cluster of strong thunderstorms have developed in
the Manhattan/Emporia region over the past half hour. The storms
are embedded in a strongly unstable (2000-3000 J/kg MLCAPE)
environment, with 1.8 inch PW values supporting heavier rainfall
in water-loaded downdrafts. The cells are likely benefiting from
weak mid-level vorticity maxima (over eastern Nebraska and western
Kansas) providing ascent. Low-level convergence along a remnant
outflow from morning convection was also likely providing a focus
for updraft development in the area.

Kinematics aloft are supportive of slow and at times erratic storm
motions along with 1-2 inch/hr rain rates beneath dominant
activity. The proximity of intense convective development and
downdraft potential (from 7C/km lapse rates aloft) suggests that
the storms will eventually form one or two small linear
segments/clusters that propagate slowly southward toward US 50 and
US 400 near/east of Wichita over the next 2-3 hours or so. Flash
flood potential should accompany this activity - especially across
east-central and northeastern Kansas where FFG thresholds are
around 1 inch/hr and could readily become exceeded. Slightly
higher rain rates may be needed with southward extent for any
appreciable flash flood risk.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4xI791ETaJy8cmcFdaUDmb0gwdXp4gCPETA56apmkQ4Cv_nYZYGrI6wvXSgOh9cUgr6x= FwXuSbLophNmoRprCcbr6yY$ for graphic product...

ATTN...WFO...DDC...EAX...GID...ICT...SGF...TOP...

ATTN...RFC...KRF...TUA...NWC...

LAT...LON 39249529 37479456 37079656 37439953 39129912=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 191903
FFGMPD
MOZ000-ARZ000-OKZ000-200100-

Mesoscale Precipitation Discussion 0962
NWS Weather Prediction Center College Park MD
302 PM EDT Tue Aug 19 2025

Areas affected...The Ozarks

Concerning...Heavy rainfall...Flash flooding possible

Valid 191902Z - 200100Z

Summary...Showers and thunderstorms developing ahead of an MCV
will expand in coverage through the aftn. Rainfall rates of
1-2"/hr are expected, which could result in 2-3" of rainfall with
locally higher amounts. Flash flooding is possible.

Discussion...The regional radar mosaic this aftn depicts rapid
expansion of increasing reflectivity associated with developing
convection from southeast Missouri through far eastern Oklahoma.
These thunderstorms are developing in response to ascent produced
through weak upper level directional divergence atop subtle height
falls as a convectively enhanced shortwave and remnant MCV tracks
southward from Missouri. An outflow boundary (OFB) ahead of this
MCV noted in satellite imagery is producing additional lift
through convergence, while general N/NW flow is producing modest
upslope ascent into the Ozarks as well. This ascent is acting upon
favorable thermodynamics characterized by PWs measured by GPS of
1.7 to 1.8 inches, around the 90th percentile for the date,
collocated with MUCAPE around 3000 J/kg south of the OFB.

Cells that have developed so far have been generally small with
narrow updrafts, which within the pulse environment (limited bulk
shear) is keeping rainfall intensity to around 0.5-1"/hr with
short temporal lifespans. However, the CAMs suggest that
thunderstorms will become more widespread and intense as the MCV
and OFB drop southward into the evening, and as coverage
increases, storm mergers and collisions will lead to regenerating
cells with longer lifetimes. During this time, PWs are likely to
increase to above 2", suggesting the thermodynamic environment
will become even more favorable as the forcing intensifies, with
the result being HREF neighborhood probabilities for 2"/hr rain
rates peaking above 30%. Although cells should steadily move
southward on mean 0-6km winds of 5-10 kts, propagation vectors may
veer sufficiently to allow redevelopment upstream suggesting that
in addition to storm mergers, some areas could receive repeating
rounds of thunderstorms. Where this occurs, total rainfall of
2-3", with locally 3-4", is possible as reflected by HREF
exceedance probabilities for 3"/6hrs of 40%.

Soils across this area are generally dry according to NASA SPoRT
due to minimal recent rainfall noted via AHPS. This has allowed
FFG to reach 3-4"/3hrs. While this should limit the magnitude and
coverage of any flash flooding, isolated impacts are possible
where any repeating cells can occur, especially within urban areas
or any more sensitive terrain.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8tbCZYWYfdBJ1voqLUBZJKdolbsMBPy_63Dm0m98mkcIwOM2NyaWtnjkPczzYOj3z9EO= mIMEX0W2eonhkyqrqVDzHaI$ for graphic product...

ATTN...WFO...LSX...LZK...MEG...PAH...SGF...TSA...

ATTN...RFC...KRF...MSR...ORN...TUA...NWC...

LAT...LON 37639064 37638986 37418952 36988951 36248997=20
35739069 35389151 35249225 35029322 34849408=20
34769465 34749508 35019555 35339540 35749483=20
36279363 36969266 37259231 37569160=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 201948
FFGMPD
GAZ000-TNZ000-ALZ000-MSZ000-210100-

Mesoscale Precipitation Discussion 0963
NWS Weather Prediction Center College Park MD
347 PM EDT Wed Aug 20 2025

Areas affected...Portions of Tennessee, Alabama, and Mississippi

Concerning...Heavy rainfall...Flash flooding possible

Valid 201947Z - 210100Z

Summary...Slow moving showers and thunderstorms will expand
through the afternoon. Rainfall rates will likely exceed 2"/hr at
times, leading to pockets of 2-4" of rainfall. This may lead to
instances of flash flooding, especially over urban areas.

Discussion...The regional radar mosaic this aftn indicates rapid
development of showers and thunderstorms from south-central TN
through central MS. This convection is developing ahead of an
approaching cold front and along a low-level convergence boundary
formed by the interaction of convective outflows and a surface
trough. Ascent across this region is being additionally enhanced
by a modest shortwave tracking E/SE near the MS/TN border.

This broad ascent is acting upon a favorable thermodynamic
environment to support heavy rainfall. PWs as measured by GPS are
between 1.8 and 2.1 inches, around the 90th percentile for the
date, overlapping MUCAPE that is between 3000-4000 J/kg south of
the cold front. This is driving the rapid expansion of convection
noted in the regional radar, with additional storms forming due to
outflow collisions and storm mergers in the generally pulse-type
environment.

Rainfall rates have been estimated via local radars to be as high
as 2-2.5"/hr from KHTX and KOHX, leading to MRMS hourly rainfall
as much as 2.5 inches. As the aftn progresses, the continued
ascent drifting southward into a ribbon of enhanced moisture
confluence could support more frequent rainfall rates above 2"/hr
as supported by HREF neighborhood probabilities, and the HRRR
15-min precipitation accumulation suggests brief rates in excess
of 3"/hr are possible. While storms should remain generally pulse
due to minimal bulk shear, and mean winds support a slow southward
advance of cells at 5-10 kts, frequent mergers and collisions will
lead to slower and at times chaotic motion which could enhance the
duration of rainfall. Where this occurs, total rainfall through
this evening could reach 2-4" as reflected by HREF 6-hr rain
probabilities exceeding 40% for 3 inches.

7-day rainfall across the area has been scattered, but in some
parts of the discussion area, especially in AL/TN, has been as
much as 300% of normal, leading to 0-10cm soil moisture from NASA
SPoRT that is above the 95th percentile. While FFG remains
elevated, and FFG exceedance probabilities are modest in response,
it is possible that any slow moving/lingering heavy rainfall could
overwhelm soils to produce rapid runoff. However, this will be
most likely across any urban areas which have the greatest
potential for isolated flash flood impacts into this evening.

Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_AxvMuSPWL7KSY07MFdiDt52-GqDaTutEI9deFy5LT48LMqp2BpjHDnlaG_CRK7RvFt6= qGV86FtNSPGNVxC_uEp8Wpg$ for graphic product...

ATTN...WFO...BMX...FFC...HUN...JAN...MEG...MRX...OHX...

ATTN...RFC...ALR...ORN...TIR...NWC...

LAT...LON 35948609 35908485 35648452 35018456 34358490=20
33818568 33458724 33288747 32828818 32448880=20
32188955 32178993 32489015 33079011 33699002=20
34638895 35448751=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 210112
FFGMPD
MSZ000-LAZ000-ARZ000-TXZ000-210600-

Mesoscale Precipitation Discussion 0964
NWS Weather Prediction Center College Park MD
911 PM EDT Wed Aug 20 2025

Areas affected...Southern Arkansas, western Mississippi, northern
Louisiana

Concerning...Heavy rainfall...Flash flooding possible

Valid 210111Z - 210600Z

Summary...Showers and thunderstorms will continue for several more
hours ahead of a cold front before waning tonight. Rainfall rates
of 2-3"/hr, while generally brief, will produce 2-3" of rain.
Instances of flash flooding are possible.

Discussion...A cold front analyzed by WPC dropping slowly across
southern Arkansas will continue to drift into Louisiana tonight.
The tail end of this front will continue to provide the impetus
for ascent through low-level convergence, aided by a subtle
shortwave dropping concurrently within the general weak northerly
flow regime. Moisture across the region is being channeled ahead
of the front and is analyzed by the SPC RAP to be above 2 inches
even in the pre-convective airmass, with GPS measurements
approaching 2.3 inches within convection. This extreme PW is
overlapping MUCAPE that is still 2000-3000 J/kg despite SBCIN,
supporting the regenerating convection seen over the past two
hours. Rainfall rates have been estimated by local radars to be
above 2.5"/hr, and MRMS 15-min rainfall has been as high as 0.8"
in a few areas (above 3"/hr measured rainfall rates).

The CAMs are struggling to resolve the current activity which is
both much more intense and widespread than progs would suggest.
With the front in place, aided by the weak shortwave energy aloft,
and modest 700mb convergence, it has become more likely that
thunderstorms will persist well after dark. This is despite a lack
of bulk shear keeping storms of the pulse variety, but outflow
boundary collisions and storm mergers in response to the
widespread nature will support additional development. With storm
motions generally slow and chaotic, and with some upstream
development also possible as propagation vectors collapse to 5 kts
and orient obliquely right of the mean wind, these intense
rainfall rates (3"/hr at times continuing) could produce 2-3" of
rain, with isolated higher amounts possible. This is in addition
to rain that has already fallen.

FFG across the area is quite elevated, generally 3-4"/3 hrs and
even 2-3"/1hr. While HREF exceedance probabilities are modest,
less than 10%, this is clearly under-forecasting the true risk.
Additionally, with rainfall rates as intense as they have been,
and with these likely to continue, 15-min rainfall of 0.75-1 inch
in some areas could quickly overwhelm soils to become runoff
despite the elevated FFG. For this reason, any storms that
continue until full convective overturning later tonight could
produce instances of flash flooding.

Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6ccWbhoL8ZCGKWfhd9EZLKyUzQYy083UtKffDFtqsrwbsW0psBep94vgit9t2bHPza9D= EATTPHIegGHhgAwO0GJwpHM$ for graphic product...

ATTN...WFO...JAN...LCH...LIX...LZK...MEG...SHV...

ATTN...RFC...ALR...FWR...ORN...TUA...NWC...

LAT...LON 34798999 34728899 34478866 33938870 33398899=20
33018941 32689000 32219065 31629093 31189131=20
30879184 30749260 30759312 31209370 31869387=20
32399385 33089345 33939271 34399201 34699105=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 211810
FFGMPD
LAZ000-TXZ000-220009-

Mesoscale Precipitation Discussion 0965
NWS Weather Prediction Center College Park MD
210 PM EDT Thu Aug 21 2025

Areas affected...portions of central through southeast Texas and
southwestern Louisiana

Concerning...Heavy rainfall...Flash flooding possible

Valid 211809Z - 220009Z

Summary...Scattered to numerous thunderstorm activity will pose an
isolated flash flood risk through 00Z/7p CDT this evening.

Discussion...Strong insolation/destabilization and the presence of
several meso-to-synoptic surface boundaries across the discussion
area has resulted in an uptick in coverage of thunderstorms over
the past half hour. The storms are in a very moist/buoyant
airmass characterized by 2+ inch PW values and 1000-2000 J/kg
MLCAPE values, favoring the eventual development of heavy rainfall
rates as storms mature. Additionally, storms are in a very weakly
sheared environment, with minimal steering flow aloft supporting
slow/erratic cell movement. Areas of 2 inch/hr rain rates are
expected at times through the afternoon hours, which poses an
isolated flash flood threat.

FFG thresholds are generally in the 2-3 inch/hr range (locally
lower near urban areas near Austin/San Antonio and Houston. These
thresholds and the pulse-type nature of the convection suggests
that any flash flood threat will be relatively isolated and
focused on urban and sensitive/low-lying areas. The bulk of the
threat should be diurnally driven and exhibit a slow southward
propagation toward coastal areas through 00Z/7p CDT.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9cFes5Y2kLXFfF92YCZhfr1qVsSj3Fm0dTE8P-1aYNI55Ix-E8MQbfOkMMLjP0fQdIOh= ZSn92Xz1I-85XNYNomPbsUA$ for graphic product...

ATTN...WFO...CRP...EWX...FWD...HGX...LCH...SHV...

ATTN...RFC...FWR...ORN...NWC...

LAT...LON 31719608 31489428 31329243 30079263 29369463=20
27699832 27719951 28070008 28930004 30049910=20
30999761=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 211850
FFGMPD
UTZ000-220049-

Mesoscale Precipitation Discussion 0967
NWS Weather Prediction Center College Park MD
249 PM EDT Thu Aug 21 2025

Areas affected...southern/central Utah

Concerning...Heavy rainfall...Flash flooding possible

Valid 211849Z - 220049Z

Summary...Scattered convection has the potential for brief heavy
rain and an isolated flash flood threat through the afternoon
hours.

Discussion...Radar/satellite imagery indicates scattered
thunderstorm developing along favored ridge lines in south-central
Utah recently. These storms are in a relatively dry low-level
environment (35-50F surface dewpoint depressions). Nevertheless,
presentation on radar and mid-level moisture representations via
satellite suggest that the environment may be a bit more
moist/unstable aloft than suggested by mesoanalyses (depicting
0.8-0.9 inch PW and minimal instability). The observational
trends are also suggestive of brief heavy rainfall potential
across the region, with a quick 0.5 inch of precipitation possible
on an isolated basis with the strongest cells. These outflow
driven storms will tend to propagate slowly northward over the
course of the afternoon, but may produce heavy rain across
terrain-favored low-lying areas/slot-canyons and burn scars.=20

Isolated instances of flash flooding are possible given the
aforementioned scenario. This diurnally driven threat should
persist through 01Z/7p MDT.

Cook

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9UGN-eqjpy1U1dwPJqazbEpL1FEoUe1P6IWfMajXr_oGVyw0RjSGKDlG56Dw17rMuTe7= jHPZMKEsfdYvPro56FV5t60$ for graphic product...

ATTN...WFO...SLC...

ATTN...RFC...STR...NWC...

LAT...LON 39731183 39721085 38841034 37511091 37011238=20
37421354 38421374 39191288=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 211844
FFGMPD
VAZ000-NCZ000-WVZ000-SCZ000-GAZ000-TNZ000-220045-

Mesoscale Precipitation Discussion 0966
NWS Weather Prediction Center College Park MD
243 PM EDT Thu Aug 21 2025

Areas affected...Southern Appalachians

Concerning...Heavy rainfall...Flash flooding possible

Valid 211845Z - 220045Z

Summary...Slow moving showers and thunderstorms will expand across
portions of the Southern Appalachians through this evening.
Rainfall rates at times may reach 3"/hr which could overwhelm
soils, especially in sensitive terrain. Flash flooding is possible.

Discussion...The GOES-E experimental day-cloud phase micro-physics
RGB this afternoon shows a rapid uptick in ice-bearing clouds
suggestive of strengthening updrafts into Cbs from NW NC through
central GA. These updrafts are associated with deepening
convection, and there has been a recent uptick in lightning
detection within these storms. This suggests that the environment
is becoming increasingly favorable for thunderstorms containing
heavy rain, as thermodynamics continues to intensify reflected by
PWs measured by GPS between 1.6 and 1.9 inches, around the 90th
percentile for the date, overlapped with MUCAPE as much as 3000
J/kg. Despite the relatively recent growth across the area,
radar-estimated rainfall rates have already exceeded 1.5"/hr
according to KGSP.

As the aftn progresses, the CAMs are in decently good agreement in
both coverage and placement of activity. It appears likely that
convection will become widespread as PWs surge to above 2" outside
of the higher terrain. This will support rain rates within
thunderstorms that will likely exceed 2"/hr (HREF neighborhood
probabilities above 30%) and may reach 3"/hr at times as reflected
by HRRR 15-min rainfall above 0.75" in a few locations. Storms
that develop will be of the pulse variety in response to limited
bulk shear, but will also move very slowly on 0-6km mean winds of
just around 5 kts. This indicates that despite the relatively
short lifetimes expected of any individual cell, total rainfall
could reach 2-3" in some areas, and this will be most likely where
any boundary collisions, storm mergers, or terrain influences can
impact the relative strength and motion of these storms.

Soil moisture across the Southern Appalachians is generally well
above normal as reflected by NASA SPoRT 0-10cm percentiles that
exceed 98% in many areas. This has reduced 1-hr FFG to as low as
1-1.5" in some areas, for which the HREF exceedance probabilities
peak above 25%. This is in addition to the general sensitivity
across this area due to the terrain, as well as within any urban
areas, so any slow moving thunderstorm could produce impacts due
to flash flooding through this evening.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-dCixfr9qBzPF4SOXCZHuus7HaXsR8sNvbBCpD0ApBYcKAGJfz3FaQ8aSDyz1ZL8KsOc= uciRjDWptOg7sWA3OnlyZx0$ for graphic product...

ATTN...WFO...FFC...GSP...MRX...RNK...

ATTN...RFC...ALR...ORN...RHA...TIR...NWC...

LAT...LON 37578044 37468009 36978015 35808076 34628216=20
34088290 33708358 33558435 33578489 33868522=20
34258544 34638551 35028530 35358470 35618366=20
35958282 36388208 36828157 37268116 37508079=20 =20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 212111
FFGMPD
SCZ000-FLZ000-GAZ000-220300-

Mesoscale Precipitation Discussion 0968
NWS Weather Prediction Center College Park MD
511 PM EDT Thu Aug 21 2025

Areas affected...Far northern FL hrough southwest SC including
much of eastern GA

Concerning...Heavy rainfall...Flash flooding possible

Valid 212110Z - 220300Z

Summary...Showers and thunderstorms will expand across eastern
Georgia through this evening. Rainfall rates of 2-3"/hr are
expected, which through slow storm motions could produce 2-4" of
rain. This may result in instances of flash flooding.

Discussion...The regional radar mosaic this afternoon shows
widespread showers and thunderstorms across much of Georgia, with
a slow expansion in coverage noted as far south as FL and east as
SC. This activity is blossoming primarily in response to a weak
low-level convergence axis noted in surface observations and 850mb
analysis, with weak directional divergence at 300mb contributing
ascent. Storms that have developed are generally pulse in nature
due to weak bulk shear, and the resulting outflows/storm mergers
are producing additional convective development.

The thermodynamic environment in the Southeast remains extremely
favorable for heavy rainfall, and is forecast to become even more
impressive though the evening. PWs as measured by GPS are around
2.1 inches, around the 90th percentile for the date, and
corresponding MUCAPE is analyzed by the SPC RAP to be around 3000
J/kg. These robust thermodynamics are supporting heavy rainfall
rates in the ongoing convection, as reflected by radar-estimated
rain rates as much as 1.5-2"/hr and MRMS measured 15-min rainfall
locally above 0.75". As PWs continue to surge to as much as 2.25
inches later this evening, these prolific rainfall rates will
likely persist, and may even intensify, as HREF 2"/hr neighborhood probabilities peak above 35% by 01Z coincident with more
widespread 0.75"/15min rainfall (3+"/hr rates) from the HRRR.

Numerous thunderstorms are expected to develop as forecast by most
available high-res CAMs, and these should move slowly in response
to weak 0-6km mean layer winds of just 5-10 kts, with at times
chaotic motion driven by collisions/mergers leading to repeating,
training, or prolonged cells. Where this occurs, total rainfall of
2-4" is possible as supported by both HREF and REFS 3"/6hr
probabilities peaking at 40-60%.

Although storms will move across soils that have some infiltration
capacity and FFG that is generally 3"/3hrs, the slow motion of
these intense rates could still overwhelm soils to produce rapid
runoff. If this occurs across any urban areas, or even if less
vulnerable regions experience multiple slow moving cells, this FFG
could be exceeded leading to instances of flash flooding.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5xDxbUQ3NhfD7V1zd-2s5v9vdMglZkgqMj4VLzEnXDC95ktT5bfTM-LQZrf3sEjDhlHa= qU6P30gZyIHLM4tA6tm1hBw$ for graphic product...

ATTN...WFO...CAE...CHS...FFC...JAX...TAE...

ATTN...RFC...ALR...NWC...

LAT...LON 33928339 33898281 33628184 32638125 32068103=20
31618106 31188118 30748131 30358135 30038134=20
29738155 29698181 29788218 29998256 30328281=20
30778311 31438350 32268360 32408360 33378383=20
33668375=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 220038
FFGMPD
AZZ000-220600-

Mesoscale Precipitation Discussion 0969
NWS Weather Prediction Center College Park MD
838 PM EDT Thu Aug 21 2025

Areas affected...Southern Arizona

Concerning...Heavy rainfall...Flash flooding possible

Valid 220037Z - 220600Z

Summary...Showers and thunderstorms along the Mogollon Rim will
drop southwest through this evening while additional storms
develop downstream. Rainfall rates of up to 1"/hr are expected,
which could result in flash flooding.

Discussion...The regional radar mosaic this aftn shows that
convection has expanded along the Mogollon Rim, and storms are
beginning to shift southwest off of the terrain. Although storm
motions have been generally slow and tied to the terrain features
thus far, anti-cyclonic flow around the large ridge of high
pressure centered near the Four Corners will cause progression of
these storms into the lower elevations. At the same time, a weak
convergence axis noted in low-level wind fields is collocated with
a plume of elevated MUCAPE above 1000 J/kg, which will support
additional thunderstorm development. This instability is paired
with PWs that were measured via the 00Z U/A sounding at KTUS to be
around 1.3 inches, or the 75th percentile for the date. This will
support at least brief heavy rain rates through the next several
hours.

So far, storms have been slow to move off the terrain, but this
will change as the 0-6km mean winds increase to 10-15 kts from the
E/NE. At the same time, a ribbon of modest but elevated bulk shear
of 20-25 kts is progged to surge across southern Arizona, and this
will support persistence of these storms as they track SW. At the
same time, additional convection is likely to develop as more
isolated storms in the lower elevations, and the interaction of
these cells could briefly pulse rainfall rates up to above 1"/hr
as progged by HREF neighborhood probabilities reaching 10-20%
between 01Z-04Z. Additionally, the HRRR forced UA WRF depicts
isolated 0.75"/1hr rain accumulations, further indicative of the
potential rain intensities within the favorable thermodynamics.

A notable inverted-V signature in the KTUS sounding combined with
impressive DCAPE and the increasing forward motion of cells from
the terrain indicates that wind, rather than rain, may be the
primary threat this evening, and explains the modest HREF
exceedance probabilities for 1"/6hrs that peak around 30%.
However, the intensity of this rainfall could still overwhelm the
soils, especially given the general vulnerability of this region
due to currently dry soils (NASA SPoRT 0-10cm soil moisture below
the 10th percentile). Although the risk appears generally
isolated, any heavy rain moving atop sensitive terrain, burn
scars, or urban areas could result in flash flood impacts through
the evening.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5lroD-MT-SY_gkzlnVM0Wl-qYpTfub53RKfMo1c3-6Z3yX1mKQBrodnkgDDpm_dwH4N-= x-jB_GdEnTAo4GRUt-WPuVc$ for graphic product...

ATTN...WFO...FGZ...PSR...TWC...

ATTN...RFC...STR...NWC...

LAT...LON 34581282 34371178 34011092 33530978 33050940=20
32380960 32151004 31851054 31521101 31461138=20
31461185 31581235 31801277 32111303 32621323=20
33221332 33661324=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

AWUS01 KWNH 220126
FFGMPD
LAZ000-TXZ000-220630-

Mesoscale Precipitation Discussion 0970
NWS Weather Prediction Center College Park MD
925 PM EDT Thu Aug 21 2025

Areas affected...Coastal Plain from the Middle TX Coast through
South-Central LA

Concerning...Heavy rainfall...Flash flooding possible

Valid 220125Z - 220630Z

Summary...Showers and thunderstorms will continue to develop and
move slowly along the TX/LA coasts this evening. Rainfall rates
may at times reach 4"/hr, which could cause 2-3" of rain with
locally higher amounts and instances of flash flooding.

Discussion...The regional radar mosaic this evening shows an
expansion of very slow moving thunderstorms aligned near the Gulf
Coast from far SW LA through near San Antonio Bay, TX. This
activity is blossoming in response to convergent ascent as
low-level north winds over the land intersect east winds on the
coast. This convergence is occurring beneath an elongated
mid-level trough axis with subtly steeper lapse rates, providing
additional ascent to the area. PWs measured on the KCRP and KLCH
were around 2.1 inches, near the 90th percentile for the date,
which is overlapping with MUCAPE of more than 2000 J/kg to produce
an impressive thermodynamic environment. This environment is
supporting radar-estimated rainfall rates from KHGX that have been
2.5-3"/hr this evening.

Although the CAMs feature a high variability in placement of heavy
rain, there is good agreement that heavy rain amounts will occur
during the next few hours. Moisture convergence along the coast
may elevate PWs to 2.25 to 2.5 inches, supporting even more
intense rain rates as forcing for ascent persists. This suggests
that even with loss of daytime instability, the elevated MUCAPE
will support intense rainfall, for which the HREF neighborhood
probabilities forecast a 40-60% chance of exceeding 2"/hr, with
brief rates reaching 4"/hr possible as suggested by the HRRR
15-min rain accumulation product showing up to 1".

While these rates themselves could be sufficient to overwhelm
soils and lead to rapid runoff, the storms containing this intense
rain will also be very slow moving to potentially prolong this
prolific rainfall. 0-6km mean winds of just 5 kts will cause
storms to drift generally to the east, but a lack of bulk shear
indicating pulse-type convection will also result in chaotic
motion during storm mergers and boundary collisions. This could
lengthen the duration of heavy rain, or cause multiple rounds, in
a few areas, leading to amounts that could reach 2-3" or locally
higher (HREF and REFS probabilities for 3"/6hrs over 30%).

FFG across the region is elevated at generally 3-4"/3hrs for which
exceedance probabilities are modest. Despite this, at least
isolated instances of flash flooding appear possible due to the
intensity of this rain, with the most likely impacts occurring
should any storm linger over more urban areas.


Weiss

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9UTroYqDAh338BSR9MARgzg82Li1kn0vvBfVdOG7v3-AcUL2t7Lg1G2Bvslq8TwZCTIV= wEluWXZW2nm921oZW_v4Vr0$ for graphic product...

ATTN...WFO...CRP...EWX...HGX...LCH...

ATTN...RFC...FWR...ORN...NWC...

LAT...LON 31139339 30959251 30359179 29809173 29599191=20
29529221 29499282 29319376 29049457 28719532=20
28259625 27869679 27679716 27719746 27879754=20
28379763 28789746 29379713 29819673 30589581=20
30819514 30999448=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.28-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)