ZCZC SPCSWOMCD ALL
ACUS11 KWNS 171725 
SPC MCD 171725 
VAZ000-MDZ000-WVZ000-OHZ000-KYZ000-171900-

MESOSCALE DISCUSSION 1553
NWS STORM PREDICTION CENTER NORMAN OK
1225 PM CDT WED AUG 17 2016

AREAS AFFECTED...FAR ERN KY...MUCH OF WV...WRN MD
PANHANDLE...PORTIONS OF WRN AND NRN VA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 171725Z - 171900Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...THUNDERSTORMS MAY PRODUCE STRONG/LOCALLY DAMAGING WIND
GUSTS THIS AFTERNOON. AREA BEING MONITORED FOR POSSIBLE WATCH
ISSUANCE.

DISCUSSION...A WEAK UPPER DISTURBANCE AHEAD OF THE MAIN UPPER TROUGH
IS TRACKING EASTWARD FROM ERN KY INTO WESTERN WV WITH ATTENDANT
INCREASE IN THUNDERSTORM COVERAGE/INTENSITY OCCURRING OVER THE LAST
HOUR OR TWO. THE DOWNSTREAM AIRMASS ACROSS MUCH OF WV INTO ADJACENT
PORTIONS OF VA HAS WARMED INTO THE 80S TO LOW 90S WITH DEWPOINTS IN
THE UPPER 60S TO LOW 70S...RESULTING IN STRONG INSTABILITY.
FURTHERMORE...DEEP LAYER EFFECTIVE SHEAR OF 25-35 KT WILL BE
SUFFICIENT FOR ORGANIZED CELLS WITH MARGINAL SUPERCELL
CHARACTERISTICS. IN FACT...ONE CELL ENTERING PUTNAM COUNTY WV WAS
SHOWING BROAD LOW-LEVEL ROTATION AS OF 17Z. 0-1 KM SHEAR WILL REMAIN
WEAK MITIGATING THE OVERALL TORNADO THREAT...BUT VERTICAL SPEED
SHEAR COUPLED WITH VERY MODEST LOW-LEVEL DIRECTIONAL SHEAR WILL BE
SUFFICIENT FOR SOME LOW-LEVEL ROTATION AND A WEAK/BRIEF TORNADO
CANNOT BE RULED OUT. THE MAIN CONCERN ACROSS THE REGION WILL BE
DAMAGING WIND GUSTS WITH WIDESPREAD 0-3 KM LAPSE RATES FROM 7-8 DEG
C/KM AND PW VALUES FROM 1.5-2.0 INCHES INCREASING CHANCES FOR STRONG
DOWNDRAFTS. THESE DOWNBURST WINDS ARE MAINLY EXPECTED TO OCCUR WITH
INDIVIDUAL CELLS OR PERHAPS MULTICELL CLUSTERS AS STORM MERGERS AND
OUTFLOW INTERACTIONS OCCUR. A WATCH MAY BE NEEDED WITHIN THE NEXT
HOUR OR SO.

..LEITMAN/DARROW.. 08/17/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LWX...RNK...PBZ...RLX...MRX...JKL...

LAT...LON   38618259 38858221 39028182 39388068 39637948 39577885
            39317862 38837863 38267889 37767949 37398028 37208076
            37088168 37098236 37418290 38048294 38618259 

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