807
AWUS01 KWNH 111830
FFGMPD
VAZ000-NCZ000-WVZ000-SCZ000-TNZ000-KYZ000-112330-
MESOSCALE PRECIPITATION DISCUSSION 1010
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
229 PM EDT TUE AUG 11 2026
AREAS AFFECTED...FAR SOUTHERN WV...WESTERN VA...WESTERN
NC...EASTERN TN...FAR EASTERN KY...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 111830Z - 112330Z
SUMMARY...SLOW MOVING CELLS PRIOR TO A QUICK MOVING SQUALL LINE
THROUGH ROUGH TERRAIN SHOULD SUPPORT 1.5"-1.75"/HR RATES AND
SCATTERED TOTALS OF 1.5-3" WHICH MAY RESULT IN LOCALIZED FLASH
FLOODING CONDITIONS.
DISCUSSION...GOES-E VISIBLE IMAGERY AND REGIONAL RADAR MOSAIC
DEPICT A MATURE SQUALL LINE MOVING SOUTH-SOUTHEAST THROUGH
SOUTHERN WV ATTM. AMPLE DEEP LAYER MOISTURE OF 1.5-1.75" (BASED
ON ELEVATION) FORWARD CONVERGENCE ALONG THE SQUALL LINE WILL
CONTINUE TO SUPPORT LOCALIZED 1-1.5"/HR RATES AS THE LINE QUICKLY
MOVES THOUGH. GIVEN COMPLEX TERRAIN AND HOURLY FFG VALUES OF
1-1.5"/HR SCATTERED INCIDENTS OF FLASH FLOODING CONTINUE TO REMAIN
A RISK AS IT TRACKS INTO FAR W VA AND NW NC IN THE NEXT FEW HOURS.
DOWNSTREAM, A SOLID CU FIELD ACROSS THE SOUTHERN APPALACHIANS
EXTENDS INTO THE EASTERN FOOTHILLS OF NORTH CAROLINA WITH A
DISTINCT EDGE EXTENDING FROM NEAR KHLX TO KMWK TO KGSO. THIS
DELINEATES A STARK SURFACE TD DROP OF 5 TO 6 DEGREES FROM THE
MID-60S IN SW VA TO THE LOW 70S EVEN THROUGH THE HIGHER TERRAIN OF
THE SMOKIES. WITH FULL INSOLATION, MLCAPES HAVE RISEN TO
2500-3000 J/KG ACROSS THE UNSTABLE AREA SOUTH OF THE DEWPOINT
BOUNDARY (WHILE REMAINING CAPPED NORTHWARD). ALOFT, SHORTWAVE
ENERGY THAT HAS DRIVEN THE FORWARD PROPAGATING SQUALL LINE WILL
ALSO PROVIDE BROAD SCALE ASCENT TO FURTHER CONVECTIVE INITIATION
ALONG/DOWNSTREAM OF THE SQUALL LINE. THESE CELLS SHOULD DEVELOP
AND BE VERY SLOW MOVING INITIALLY GIVEN THE UPSTREAM
HEIGHT-FALLS/FORCING APPROACHING. THE AMPLE MOISTURE OF 1.5-1.75"
AND 15-20KTS OF SOUTHWESTERLY INFLOW SHOULD HELP TO SUPPORT RATES
OF 1.5-1.75"/HR AND WITH RESIDENCY OF AN HOUR OR SO, WIDELY
SCATTERED TOTALS OF UP TO 2-2.5" ARE POSSIBLE. COMBINE THIS WITH
THE APPROACHING SQUALL LINE AND FOCUSED TOTALS OF 3"+ ARE
POSSIBLE. FFG VALUES ARE SLIGHTLY HIGHER IN THE SOUTHERN
APPALACHIANS COMPARED TO AREAS FURTHER NORTH (~1.5") AND INCREASE
TO ~2"/HR AND 2-2.5"/3HRS THROUGH THE FOOTHILLS TO SUGGEST, THESE
TOTALS MAY RESULT IN LOCALIZED INCIDENT(S) OF FLASH FLOODING
THROUGH THE EVENING.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...GSP...JKL...MRX...RAH...RLX...RNK...
ATTN...RFC...ALR...ORN...RHA...TIR...NWC...
LAT...LON 37548152 37508031 36957984 35967885 35617916
34918037 35448196 35088402 35628440 36378387
37078322 37428262
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