520
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

...Please see www.wpc.ncep.noaa.gov for graphic product...

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