MESO: Mesoscale Discussion 1551

ACUS11 KWNS 231659
SWOMCD
SPC MCD 231658
NCZ000-VAZ000-SCZ000-TNZ000-GAZ000-231930-

MESOSCALE DISCUSSION 1551
NWS STORM PREDICTION CENTER NORMAN OK
1158 AM CDT MON JUL 23 2012

AREAS AFFECTED...MUCH OF NC...NRN SC...SRN VA...ERN TN...FAR NERN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 231658Z - 231930Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A THREAT FOR ISOLATED SEVERE THUNDERSTORMS WILL EXIST
ACROSS PARTS OF THE SRN APPALACHIANS EWD TO THE ATLANTIC COAST.
WHILE CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED THROUGH THE
AFTERNOON...WW ISSUANCE IS CURRENTLY UNLIKELY.

DISCUSSION...WITH THE REGION LYING IN THE BASE OF A MID-LEVEL TROUGH
ENCOMPASSING THE MID-ATLANTIC NWD INTO NEW ENGLAND...20-25 KT OF
WLY/WNWLY 700-500-MB FLOW OVERLAYS THE REGION. THIS IS CONTRIBUTING
TO ONLY MODEST DEEP SHEAR OVER THE AREA...WITH AOB 20 KT OF 0-6-KM
BULK SHEAR INDICATED BY 12Z AREA RAOBS. HOWEVER...ACCELERATION OF
THE MID-LEVEL FLOW WILL OCCUR OVER THE AREA CONCURRENT WITH
MID-LEVEL HEIGHT FALLS TO THE NORTH...AND THIS WILL CONTRIBUTE TO AN
INCREASE IN DEEP SHEAR THROUGH THE DAY.

STORMS ARE INITIALLY DEVELOPING FROM AN ACCAS FIELD OVER ERN TN THAT
COINCIDES WITH A ZONE OF 850-700-MB WARM ADVECTION. THESE STORMS
WILL LIKELY INTENSIFY WHILE TRACKING EWD ACROSS ERN TN...WRN
NC...AND SWRN VA. ADDITIONAL CONVECTION WILL LIKELY EVOLVE DURING
THE NEXT HOUR OR TWO FROM THE INCREASINGLY AGITATED CUMULUS FIELD
OVER THE SRN APPALACHIANS...AND WILL MOVE OVER THE PIEDMONT REGION
THROUGH THE DAY. ISOLATED TO SCATTERED STORMS SHOULD ALSO DEVELOP
OVER INLAND AREAS INVOF AN APPALACHIANS-LEE TROUGH...AND ALONG
DEVELOPING SEA-BREEZE BOUNDARIES OVER THE COASTAL PLAIN.

MODIFIED GREENSBORO/MOREHEAD CITY NC 12Z RAOBS SUGGEST MLCAPE HAS
ALREADY INCREASED TO 2000-3000...AND INSOLATION WILL LIKELY
CONTRIBUTE TO ADDITIONAL DESTABILIZATION THROUGH THE DAY. THIS WILL
SUPPORT VIGOROUS UPDRAFTS/DOWNDRAFTS...WITH ISOLATED DMGG WIND GUSTS
AND PERHAPS MARGINALLY SVR HAIL POSSIBLE. INITIALLY LACKING DEEP
SHEAR WILL LIKELY LIMIT CONVECTIVE ORGANIZATION AND THE OVERALL SVR
THREAT. HOWEVER...WITH A MODEST INCREASE IN DEEP SHEAR EXPECTED
THROUGH THE DAY...THERE MAY BE A TENDENCY FOR MORE
ORGANIZED/PERSISTENT MULTICELL CONVECTIVE CLUSTERS TO EVOLVE WITH A
RELATIVELY HIGHER THREAT FOR DMGG WING GUSTS...ESPECIALLY ACROSS
CNTRL/ERN NC AND SRN VA. WHILE WW ISSUANCE IS CURRENTLY
UNLIKELY...WW ISSUANCE POTENTIAL MAY BE RE-EVALUATED LATER IN THE
DAY SHOULD A MORE ORGANIZED SVR THREAT APPEAR TO EVOLVE.

..COHEN/HART.. 07/23/2012

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

ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CAE...GSP...MRX...
FFC...

LAT...LON 36527581 35617549 35017571 34577702 34577928 34748304
34908429 35368446 36188369 36858213 37058033 37127807
37067647 36527581

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