[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 132020
SWOMCD
SPC MCD 132020
VAZ000-NCZ000-SCZ000-WVZ000-GAZ000-TNZ000-132215-

MESOSCALE DISCUSSION 1968
NWS STORM PREDICTION CENTER NORMAN OK
0320 PM CDT SAT AUG 13 2011

AREAS AFFECTED...FAR SERN WV...WRN VA...WRN NC...CNTRL/WRN SC...ERN
GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 132020Z - 132215Z

ISOLATED STORMS COULD PRODUCE DMGG WIND GUSTS INTO THE LATE
AFTERNOON HOURS. THE LACK OF CONVECTIVE ORGANIZATION AND ISOLATED
NATURE OF THE SVR THREAT SHOULD PRECLUDE THE NEED FOR A WW.

THE AIR MASS ACROSS MUCH OF THE DISCUSSION AREA HAS BECOME
MODERATELY UNSTABLE /I.E. MLCAPE VALUES OF 1000-2500 J PER KG/ OWING
TO SUFFICIENT HEATING AMIDST RICH BOUNDARY-LAYER MOISTURE -- SFC
DEWPOINTS IN THE UPPER 60S TO THE LOWER 70S. OROGRAPHIC ASCENT OVER
THE CNTRL/SRN APPALACHIANS...COMBINED WITH WEAK SFC CONVERGENCE
ALONG A REMNANT FRONT AND ATTENDANT SFC LOW OVER NRN/ERN GA AND SRN
SC...HAS SUPPORTED THE DEVELOPMENT OF SCATTERED CONVECTION THIS
AFTERNOON. FURTHERMORE...THE GLANCING INFLUENCE OF A SUBTLE
MID-LEVEL IMPULSE SWINGING THROUGH ERN KY...EVIDENT IN RECENT WATER
VAPOR IMAGERY...COULD PROVIDE SUFFICIENT ASCENT FOR AN INCREASE IN
CONVECTION ACROSS PORTIONS OF SWRN VA AND FAR SERN WV BETWEEN
21-00Z. WITH THE STRONGER MID-LEVEL FLOW DISPLACED TO THE NW OF THE
REGION...EFFECTIVE BULK SHEAR MAGNITUDES AOB 20 KT WILL MAINTAIN
PRIMARILY A PULSE CONVECTIVE MODE. AS STORMS COLLAPSE...A THREAT FOR
WET MICROBURSTS PRODUCING DMGG WIND GUSTS WILL EXIST ON AN ISOLATED
BASIS GIVEN DCAPE VALUES AOA 900 J/KG. HOWEVER...THE LACK OF
STRONGER VERTICAL SHEAR / FORCING WILL LARGELY PREVENT CONVECTION
FROM EXHIBITING MORE ORGANIZED ATTRIBUTES OR PERSISTENCE. STORMS
WILL LIKELY WEAKEN AFTER 00Z AS DIABATIC HEATING WANES.

..COHEN.. 08/13/2011

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

ATTN...WFO...RAH...ILM...RNK...CHS...CAE...GSP...MRX...FFC...

LAT...LON   34967982 33758005 32778099 32548216 33128355 34818326
            35618217 36428165 37258130 37868041 37797951 36777912
            34967982


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