Mesoscale Precipitation Discussion 0756
NWS Weather Prediction Center College Park MD
1254 PM EDT Sat Jul 19 2025

Areas affected...portions of the central Appalachians

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

Valid 191653Z - 192253Z

Summary...Scattered thunderstorms are developing atop sensitive
ground conditions due to prior rainfall.  These trends should
continue through the early evening.  Flash flooding is likely.

Discussion...Scattered thunderstorms were gradually increasing in
coverage and intensity across the area.  The storms are in a
weakly forced environment, although abundant moisture and
instability (1.6-2 inch PW and 1000 J/kg MLCAPE) were supporting
efficient rainfall processes with the deeper and more dominant
convection.  Weak westerly steering flow aloft was resulting in
15-20 knot storm motions that, when combined with the
moisture/instability combo, were prompting areas of 0.5-1 inch/hr
rain rates.  These rates were already approaching suppressed FFG
thresholds (generally in the 0.25-1 inch/hr range), highlighting
sensitive ground conditions from abundant rainfall over the past
few weeks.

With several hours of peak heating left in the diurnal cycle,
models/obs suggest that convection will continue to expand in
coverage and intensity through the afternoon.  The increase in
coverage should result in greater chances for cell mergers and
locally enhanced rainfall rates due to mesoscale convective
processes.  Spots of 1.5 inch/hr rain rates can be expected at
times, which would readily exceed local FFG in most areas and
result in locally significant flash flood potential.  Much of this
threat will be diurnally driven with flash flood potential
persisting through 23Z/7p EDT.  It is worth noting that deeper,
organized convection across the Lower Ohio Valley will result in
renewed/continued flash flood potential across the area, and this
threat could extend beyond 23Z as a result.

Cook

ATTN...WFO...GSP...ILN...JKL...LWX...MRX...OHX...PBZ...RLX...
RNK...

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

LAT...LON   39677952 39507829 39017791 38137832 37247932
            36718033 36198196 35858399 36418476 37438421
            38528308 39438103