AWUS01 KWNH 281404
FFGMPD
VAZ000-NCZ000-WVZ000-TNZ000-KYZ000-282000-

Mesoscale Precipitation Discussion 0875
NWS Weather Prediction Center College Park MD
1003 AM EDT Tue Jul 28 2026

Areas affected...Southern West Virginia, Southwest Virginia,
Eastern Tennessee, and Western North Carolina

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

Valid 281400Z - 282000Z

SUMMARY...2 inch/hour rainfall rates with a series of disturbances
riding along a warm front could cause additional flash flooding
into the mountains into this afternoon. Flash flooding possible.

DISCUSSION...Several clusters of storms moving southeastward along
a warm front that has banked along the southern Appalachians could
cause additional flash flooding into this afternoon. The storms
across southwestern West Virginia this morning have a history of
producing flash flooding due to multiple inch per hour rainfall
rates. The heaviest of the rain has now reached the southern tip
of West Virginia and will be heading into southwest Virginia over
the next few hours. Meanwhile a largely separate cluster of storms
over northeastern Tennessee will continue pressing southeastward
towards the Great Smoky Mountain N.P. As MUCAPE values remain in
the 1,000-1,500 J/kg range across far western North Carolina, it
appears the instability should allow for the storms to maintain
themselves into the convective minimum in the late morning as the
larger MCS transitions to surface based and much more widely
scattered convection across this region into this afternoon.

FFGs are particularly low along most of the VA/TN border, in the
1-1.5 inch/hour range. For the rest of the area highlighted in
this MPD, FFGs range between 1.5 and 2 inches per hour. Behind the
storms early this afternoon, instability is expected to rapidly
increase due to both maximum daytime heating as well as
instability advection from the west, peaking between 2,500 and
3,500 J/kg, with PWATs remaining around 1.75 inches. The plentiful
instability and moisture suggests that when afternoon storms fire
along the mountains this afternoon, they will be capable of
multiple inch/hour rainfall rates.

CAMs guidance (particularly the HRRR & RRFS) suggest the storms
this afternoon will come in multiple waves, tracking southward
across this region. While the storms should be fast-moving,
they'll follow one another, fairly closely, so minimal dry time is
expected in between. Given the already low FFGs in this region,
this could result in additional flash flooding. The storms could
continue, especially over Tennessee and North Carolina, beyond the
time of this discussion, so an update appears probable.

Wegman

ATTN...WFO...GSP...JKL...MRX...RLX...RNK...

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

LAT...LON 37978167 37708039 37408006 36928039 36688068
35718173 35238228 35168300 35258376 35528418
35948414 36548369 37038299 37638248 37858233

$$
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