MESO: Mesoscale Discussion 1248

ACUS11 KWNS 261831
SWOMCD
SPC MCD 261830
NCZ000-SCZ000-VAZ000-GAZ000-TNZ000-262100-

MESOSCALE DISCUSSION 1248
NWS STORM PREDICTION CENTER NORMAN OK
0130 PM CDT WED JUN 26 2013

AREAS AFFECTED...NC...SC...FAR ERN TN...PORTIONS OF ERN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 261830Z - 262100Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...THERE WILL EXIST AN ISOLATED POTENTIAL FOR SVR
THUNDERSTORMS THROUGH THE AFTERNOON...THOUGH THE ISSUANCE OF A WW IS
NOT ANTICIPATED.

DISCUSSION...MODERATE TO STRONG DESTABILIZATION IS UNDERWAY FROM
PARTS OF THE SRN APPALACHIANS EWD TO THE ATLANTIC COAST...AS
APPRECIABLE INSOLATION IS RESPONSIBLE FOR DIABATIC HEATING OF THE
BOUNDARY LAYER AMIDST RICH LOW-LEVEL MOISTURE -- I.E. SFC DEWPOINTS
IN THE UPPER 60S AND LOWER 70S. THIS IS SUPPORTING MLCAPE VALUES OF
AROUND 1500-2500 J/KG PER MODIFIED 12Z RAOBS. THUNDERSTORMS WILL
LIKELY CONTINUE TO INCREASE IN COVERAGE AND INTENSITY ACROSS THE MCD
AREA PARTLY OWING TO LOW-LEVEL ASCENT FOCUSED INVOF THE FOLLOWING
FEATURES:
/1/ TERRAIN-DRIVEN CIRCULATIONS AROUND THE APPALACHIANS...
/2/ SEA BREEZE CONVERGENCE ZONES ALONG THE ATLANTIC COASTAL PLAIN
REGION...
/3/ THE LEADING EDGE OF OUTFLOW ASSOCIATED WITH A
NNE/SSW-ORIENTED...DISORGANIZED LINE OF CONVECTION APPROACHING FAR
ERN TN FROM THE W...
/4/ RESIDUAL OUTFLOW BOUNDARIES FROM CONVECTION ACROSS CNTRL SC...
/5/ STRENGTHENING PLANETARY BOUNDARY LAYER CIRCULATIONS AMIDST A
NEARLY UNCAPPED THERMODYNAMIC PROFILE.

GENERALLY WEAK DEEP SHEAR ACROSS A LARGE PART OF THE AREA WILL
FOSTER LIMITED CONVECTIVE ORGANIZATION/SUSTENANCE...THOUGH ISOLATED
INSTANCES OF DMGG WIND GUSTS AND POSSIBLY MARGINALLY SVR HAIL CANNOT
BE RULED OUT WITH THE MOST INTENSE STORMS OWING TO THE LARGE AMOUNT
OF BUOYANCY. HOWEVER...AREA VWP DATA INDICATE AROUND 20 TO LOCALLY
25 KT OF WSWLY TO WNWLY MID-LEVEL FLOW IN THE BASE OF A WEAK
MID-LEVEL TROUGH...WHICH COULD SUPPORT SUFFICIENT 0-6-KM BULK SHEAR
FOR A COUPLE OF LOOSELY ORGANIZED MULTICELL CLUSTERS. ENSUING
STRONGER/MERGING COLD POOLS MAY YIELD LOCALIZED AREAS OF STRONGER
OUTFLOW WINDS...AIDED BY WATER LOADING PROCESSES WITH PW VALUES OF
1.5 TO 1.9 INCHES.

..COHEN/KERR.. 06/26/2013

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

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

LAT...LON 33988353 35208421 36478344 36547966 36367596 35217630
33817845 32448054 32638202 33988353

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