MESO: Mesoscale Discussion 1377

ACUS11 KWNS 242042
SWOMCD
SPC MCD 242042
SCZ000-GAZ000-NCZ000-TNZ000-ALZ000-MSZ000-ARZ000-242215-

MESOSCALE DISCUSSION 1377
NWS STORM PREDICTION CENTER NORMAN OK
0342 PM CDT FRI JUN 24 2011

AREAS AFFECTED...SERN AR...NRN/CNTRL MS...NRN/CNTRL AL...SERN
TN...NRN GA...FAR WRN SC...FAR SWRN NC

CONCERNING...SEVERE THUNDERSTORM WATCH 546...

VALID 242042Z - 242215Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 546
CONTINUES.

MULTIPLE CONVECTIVE CLUSTERS CONTINUE TO DEVELOP NEAR AND SOUTH OF
AN INCREASINGLY INDISTINGUISHABLE SFC FRONTAL ZONE DRAPED ACROSS
PORTIONS OF THE TENNESSEE VALLEY AND LOWER MS VALLEY REGIONS.
CONVECTION HAS ORGANIZED INTO LINEAR SEGMENTS ACROSS PORTIONS OF NRN
MS INTO NWRN AL...AND ACROSS NERN AL INTO NWRN GA. WITH THIS
CONVECTION BEGINNING TO OUTRUN THE STRONGER DEEP-LAYER WIND SHEAR
CONFINED TO THE FRONTAL ZONE /PER AREA VWP DATA/...THE PRIMARY
MECHANISM FOR MAINTAINING CONVECTION FARTHER SOUTH WILL BE THE
INTERACTION OF COLD POOL CIRCULATIONS WITH A VERY UNSTABLE AIR MASS
/MLCAPE VALUES OF 2500 TO 3500 J PER KG/. THIS DEGREE OF INSTABILITY
WILL MAINTAIN PROPAGATION OF VIGOROUS UPDRAFTS INTO THE UNSTABLE AIR
SOUTH OF ONGOING ACTIVITY THROUGH THE AFTERNOON...WITH A THREAT FOR
MARGINALLY SEVERE HAIL. HOWEVER...THE PRIMARY SEVERE THREAT WILL BE
DMGG WIND GUSTS GIVEN DCAPE VALUES IN EXCESS OF 1000
J/KG...PARTICULARLY WHERE MORE ORGANIZED COLD POOLS BECOME
ESTABLISHED.

OUTSIDE OF WW546...A COUPLE OF AREAS OF ISOLATED STRONG TO SVR STORM
POTENTIAL WILL EXIST:
1. EAST OF WW546 INTO PORTIONS OF NERN GA...FAR WRN SC...AND FAR
SWRN NC...FRONTAL CONVERGENCE AND OROGRAPHIC EFFECTS AMIDST A
MODERATELY TO VERY UNSTABLE AIR MASS COULD PROMOTE A FEW STRONG TO
SVR STORMS. HOWEVER...WITH THIS REGION DISPLACED TO THE EAST OF
STRONGER COLD POOL FORCING...AN ORGANIZED SVR THREAT IS NOT EXPECTED
TO ENSUE.
2. WEST OF WW546 IN PORTIONS OF SERN AR...A STRONG STORM OR TWO
COULD DEVELOP INVOF THE REMNANT OUTFLOW BOUNDARY EMANATING FROM
EARLIER ELEVATED CONVECTION UPSTREAM. HOWEVER...THE SHALLOW NATURE
OF THE ASSOCIATED CONVERGENCE WILL LIKELY MITIGATE A MORE ROBUST
CONVECTIVE THREAT.

..COHEN.. 06/24/2011

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

ATTN...WFO...GSP...MRX...FFC...OHX...BMX...HUN...MEG...JAN...
LZK...

LAT...LON 34359222 34529110 34798880 35228663 35908455 35398300
34638223 33858272 33358389 32838681 32378851 32608984
33049114 33379220 33739258 34359222

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