AWUS01 KWNH 011213
FFGMPD
PAZ000-MDZ000-WVZ000-OHZ000-KYZ000-INZ000-011810-

Mesoscale Precipitation Discussion 0566
NWS Weather Prediction Center College Park MD
812 AM EDT Tue Jul 01 2025

Areas affected...Portions of the Upper Ohio Valley

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

Valid 011210Z - 011810Z

SUMMARY...Ongoing showers and embedded thunderstorms across the
Ohio Valley are expected to increase in coverage this morning,
while potentially repeating and containing rainfall rates briefly
over 2"/hr. Low FFG and saturated soils in the region elevate the
potential for isolated to scattered instances of flash flooding
through at least midday.

DISCUSSION...GOES-EAST WV-ML imagery this morning shows a
pronounced upper trough sliding across the Great Lakes and Midwest
while strong northeasterly flow aloft occurs downstream over the
Upper Ohio Valley. Showers and embedded thunderstorms are already
evident on radar this morning and mostly progressing
east-northeast ahead of an approaching cold front. Model soundings
in the Ohio Valley suggest convective temperatures around 80
degrees, which should be realized after a few hours of mid-morning
sunlight. This will allow for thunderstorm coverage to blossom
quickly both ahead and along the approaching cold front, which
will increase the scattered flash flooding threat. Precipitable
water values remain high when compared to climatology with values
ranging from 1.7-2.1" (highest over KY and southern IN) per SPC's
mesoanalysis, allowing for thunderstorms to contain efficient
rainfall and hourly rates potentially reaching 2-2.5".
Additionally, westerly flow throughout the column will support any
activity forming ahead of the cold front to potentially train in
an east-west orientation.

Both HRRR and experimental RRFS guidance this morning show the
potential for isolated 2-3" totals by about 18z and the 06z HREF
depicts low chances (20-25%) of exceeding 3". However, this part
of the country contains saturated and sensitive terrain
susceptible to flash flooding. NASA SPoRT highlights 0-40cm soil
moisture percentiles above the 80th percentile across much of
southern OH and southwest PA. Additionally, FFG remains low and is
largely below 2" in 3 hours, something well within reach on a
scattered basis per the latest available CAMs. Given the largely
isolated to scattered nature of convection and the potential for a
localized linear axis of repeating cells, flash flooding is
considered possible. Should convection repeat over communities
most prone to flooding and given the moist environment at hand,
locally considerable flooding is also possible through at least
midday.

Snell

ATTN...WFO...CLE...CTP...ILN...IND...JKL...LMK...PBZ...RLX...

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

LAT...LON 40577916 40087886 39217957 38388090 37968258
37778400 37728559 38098620 38828602 39658527
40128429 40368288 40518098

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AWUS01 KWNH 070921
FFGMPD
TNZ000-KYZ000-INZ000-ILZ000-MOZ000-071520-

Mesoscale Precipitation Discussion 1165
NWS Weather Prediction Center College Park MD
520 AM EDT Tue Oct 07 2025

Areas affected...Portions of the Mid South and Lower Ohio Valley

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

Valid 070920Z - 071520Z

SUMMARY...Heavy rainfall still impacting portions of the Mid-South
early this morning will become increasingly focused across the
Lower OH Valley over the next several hours. Some isolated to
scattered areas of flash flooding will be possible where any
cell-training of showers and thunderstorms occur.

DISCUSSION...A well-defined surface low and associated mid-level
vort center is beginning to edge into the Lower OH Valley along
with a pronounced surge of tropical moisture. A southerly
low-level jet of 30 to 40 kts continues to focus rather strong
warm air advection and moisture transport around the eastern flank
of the low center, and this combined with modest instability and
some upper-level jet divergence should support broken areas of
heavy rainfall overspreading the Lower OH Valley this morning.

MLCAPE values are only on the order of 500 to 750 J/kg, but the
moisture convergence parameters are rather strong around the
northeast flank of the vort energy and especially near the low
center itself. This is favoring some stronger convective elements
with highly efficient rainfall owing to warm rain/relatively
shallow-topped convection. Some embedded colder convective tops
are occurring in sporadic bursts, and these smaller scale clusters
of convection have been capable of producing rainfall rates on the
order of 1.5 to 2.5 inches/hour.

As this energy begins lifting northeastward across the Lower OH
Valley this morning, there is expected to be some gradual
interaction with an upstream cold front approaching the OH Valley
from the northwest. This will support a more frontogenetical
component to the heavy rainfall threat and should support a more
elongated southwest to northeast axis of heavy rain with embedded
convection.

The 00Z HREF/REFS suites of guidance support some localized swaths
of 2 to 4+ inches of rain going through late this morning, with a
spotty 5+ inch total not out of the question where any
cell-training of convection occurs. The heavier and more
concentrated areas of rainfall should be close to the OH River
involving areas of far southeast IL, western and northwest KY and
into far southern IN.

Antecedent conditions across the region are generally on the dry
side, but the rainfall potential this morning is expected to be
enough to drive a threat for isolated to scattered areas of flash
flooding. This will especially be the case in vicinity of the more
urbanized areas.

Orrison

ATTN...WFO...ILN...IND...JKL...LMK...MEG...OHX...PAH...

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

LAT...LON 39008471 38588377 37748383 37098453 36388586
36088694 36008780 35988834 36028894 36278967
36758973 37398939 38028844 38508736 38958580

$$
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