[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 181859
SWOMCD
SPC MCD 181859
VAZ000-NCZ000-WVZ000-SCZ000-TNZ000-GAZ000-182100-

MESOSCALE DISCUSSION 2003
NWS STORM PREDICTION CENTER NORMAN OK
0159 PM CDT THU AUG 18 2011

AREAS AFFECTED...PORTIONS OF WRN VA...WRN NC...NWRN SC...FAR NERN
GA...FAR ERN TN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 181859Z - 182100Z

WHILE A FEW STORMS COULD PRODUCE GUSTY WINDS...THE OVERALL SVR
THREAT WILL LIKELY REMAIN MINIMAL...THUS PRECLUDING THE NEED FOR A
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ASCENT OFFERED BY A SUBTLE MID-LEVEL VORT MAX EMBEDDED WITHIN BROAD
CYCLONIC FLOW OVER THE MID-ATLANTIC STATES /PER RECENT WATER VAPOR
IMAGERY/ IS BEING AUGMENTED BY SFC CONVERGENCE ALONG A TROUGH LYING
IN THE LEE OF THE APPALACHIANS PER 18Z SFC MESOANALYSIS. THIS
ASCENT...FURTHER REINFORCED BY OROGRAPHIC FORCING AND JUXTAPOSED
WITH MLCAPE VALUES OF 1000-2000 J/KG PER MODIFICATIONS TO THE 12Z
BLACKSBURG VA RAOB TO ACCOUNT FOR CURRENT OBS...IS FOSTERING THE
DEVELOPMENT OF ISOLATED TO SCATTERED CONVECTION NEAR AND JUST EAST
OF THE BLUE RIDGE. CONVECTION COULD INCREASE IN NUMBER/INTENSITY
WHILE BEING STEERED EWD OVER ADJACENT SECTIONS OF THE PIEDMONT
REGION...WHERE DESTABILIZATION OWING TO AMPLE INSOLATION IS ONGOING.
FURTHERMORE...A VERY MODEST ENHANCEMENT TO THE MID-LEVEL FLOW IN
ASSOCIATION WITH THE VORT MAX IS GENERATING EFFECTIVE BULK SHEAR
MAGNITUDES OF 20-30 KT...PRIMARILY NEAR AND ADJACENT TO THE SRN
APPALACHIANS. THIS SHEAR COULD SUPPORT OCCASIONAL MULTICELL
CONVECTION...WITH WEAKER VERTICAL SHEAR ELSEWHERE MORE SUPPORTIVE OF
PULSE CONVECTION. GUSTY WINDS WILL BE THE MAIN CONCERN WITH THIS
ACTIVITY...AND AN ISOLATED INSTANCE OR TWO OF DMGG WIND GUSTS CANNOT
ENTIRELY BE RULED OUT. HOWEVER...THE LACK OF STRONGER FORCING /
VERTICAL SHEAR SHOULD LARGELY PREVENT CONVECTION FROM ACHIEVING ANY
SUBSTANTIAL ORGANIZATION AND MITIGATE THE SVR THREAT.

..COHEN.. 08/18/2011

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

ATTN...WFO...AKQ...LWX...RAH...RNK...GSP...MRX...FFC...

LAT...LON   36098315 36728195 37637997 38337858 37647827 36207964
            34668213 34608398 35188428 36098315

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