Sunday, June 28, 2009

Severe Storms This Afternoon


MESOSCALE DISCUSSION 1365
NWS STORM PREDICTION CENTER NORMAN OK
1139 AM CDT SUN JUN 28 2009

AREAS AFFECTED...ERN TN...ERN AL...NRN/CENTRAL GA AND FAR WRN NC

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 281639Z - 281745Z

THUNDERSTORMS ARE EXPECTED TO DEVELOP DURING THE NEXT HOUR OR SO
ACROSS PORTIONS OF ERN TN...NERN AL AND NWRN GA WITH A POTENTIAL FOR
SEVERE MULTICELL STORMS. BACK DOOR FRONT/WEAKER INSTABILITY
STRETCHING N-S FROM ERN GA INTO EXTREME ERN TN SHOULD MARK THE ERN
EXTENT OF SEVERE POTENTIAL. ONCE STORMS DEVELOP THEY WILL SPREAD
SEWD INTO PORTIONS OF EAST CENTRAL AL/CENTRAL GA/FAR WRN NC LATER
THIS AFTERNOON. A WW WOULD BE NEEDED ONCE SURFACE BASED STORMS
DEVELOP.

AT 16Z...A WEAK COLD FRONT STRETCHED FROM NEAR LEX SWWD INTO MIDDLE
TN...IN THE BNA AREA...AND INTO NRN MS NEAR OXFORD. AHEAD OF THE
FRONT...MOSTLY SUNNY SKIES HAD WARMED TEMPERATURES WELL INTO THE 80S
AND LOWER 90S...RESULTING IN A STRONGLY UNSTABLE AIR MASS...MLCAPES
UP TO 3000 J/KG. THIS STRONG INSTABILITY COMBINED WITH WINDS ALOFT
VEERING FROM WLY TO NWLY AND MID LEVEL WINDS AT 20-25 KT WILL BE
SUPPORTIVE OF SEVERE MULTICELL STORMS. PW VALUES NEAR 2 INCHES AND
STEEP LAPSE RATES IN THE LOWER 2 KM SUGGEST WET MICROBURSTS/WIND
DAMAGE SHOULD BE THE PRIMARY THREAT.

..IMY.. 06/28/2009

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