Flash Flood Guidance
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Issued by NWS
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890
AWUS01 KWNH 121941
FFGMPD
VAZ000-NCZ000-130130-
Mesoscale Precipitation Discussion 1263
NWS Weather Prediction Center College Park MD
340 PM EDT Sat Sep 12 2026
Areas affected...South-Central to Southeast VA...North-Central to
Northeast NC
Concerning...Heavy rainfall...Flash flooding possible
Valid 121940Z - 130130Z
SUMMARY...Scattered clusters of heavy showers and thunderstorms
may promote some localized and mainly urban areas of flash
flooding going through this evening.
DISCUSSION...The latest GOES-E visible satellite imagery suggests
plenty of instability across the southern Mid-Atlantic region with
a regionally agitated CU/TCU field noted, and especially over
south-central to southeast VA and into areas of north-central to
northeast NC where scattered clusters of showers and thunderstorms
are already evolving.
Cooling convective tops are noted in close proximity to a
quasi-stationary front that is draped west to east near the VA/NC
border, and the frontal convergence coupled with a strongly
unstable and very moist airmass should promote some additional
expansion of convection over the next few hours.
MLCAPE values of 1500 to 2500+ J/kg and PWs of 2.0 to 2.25 inches
will support very high rainfall rates capable of reaching 2.5
inches/hour with the strongest convective cells. Relatively slow
cell-motions coupled with at least some potential for cell-mergers
will favor potential for some rainfall totals reaching 3 to 4+
inches at least on an isolated basis.
The 12Z HREF/REFS suite strongly supports this rainfall potential,
and while the FFGs across the region are rather high, the setup
should favor at least a localized flash flood threat with
generally the urban areas at greatest risk for impacts going
through the evening hours.
Orrison
...Please see www.wpc.ncep.noaa.gov for graphic product...
ATTN...WFO...AKQ...MHX...RAH...RNK...
ATTN...RFC...ALR...RHA...NWC...
LAT...LON 37807689 37537574 36827542 36197557 35837606
35507721 35427863 35677960 36228021 36808010
37357939 37707821