MESO: Mesoscale Discussion 0800

ACUS11 KWNS 131542
SWOMCD
SPC MCD 131541
FLZ000-ALZ000-131745-

MESOSCALE DISCUSSION 0800
NWS STORM PREDICTION CENTER NORMAN OK
1041 AM CDT SUN MAY 13 2012

AREAS AFFECTED...WRN AND CNTRL FL PANHANDLE INTO EXTREME SERN CORNER
OF AL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 131541Z - 131745Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...STORMS WITH OCCASIONAL SUPERCELL STRUCTURES DEVELOPING
FROM THE NCNTRL GULF INTO THE WRN FL PANHANDLE MAY CONTINUE TO POSE
A THREAT FOR A COUPLE OF BRIEF TORNADOES AND ISOLATED DAMAGING WIND
GUSTS INTO EARLY AFTERNOON. OVERALL THREAT IS LIMITED IN AREAL
COVERAGE. A WW DOES NOT APPEAR WARRANTED UNLESS STORMS BEGIN TO SHOW
AN INCREASE IN MESOCYCLONE STRENGTH.

DISCUSSION...LATE THIS MORNING A WARM FRONT WAS LOCATED FROM THE
NERN GULF WWD INTO THE FL PANHANDLE WHERE IT INTERSECTS A
PRE-FRONTAL CONVERGENCE ZONE. A MOIST WARM SECTOR EXISTS IN VICINITY
OF AND SOUTH OF THE WARM FRONT WITH DEWPOINTS NEAR 70. DESPITE
PRESENCE OF RICH LOW LEVEL MOISTURE...INSTABILITY REMAINS SOMEWHAT
MARGINAL /500-1000 J/KG MLCAPE/ DUE TO MOIST ADIABATIC MID LEVEL
LAPSE RATES AND WIDESPREAD CLOUDS. STORMS WILL LIKELY CONTINUE
DEVELOPING ALONG THE PRE-FRONTAL CONVERGENCE ZONE INTO THE
AFTERNOON. THE 0-1 KM HODOGRAPHS FROM VWP DATA INDICATE 150-200
M2/S2 STORM RELATIVE HELICITY NEAR AND JUST NORTH OF THE WARM FRONT.
HOWEVER...MID LEVEL FLOW IS AOB 30 KT WITH SHEAR THROUGH A DEEPER
LAYER FROM 30-35 KT WHICH APPEARS SUPPORTIVE OF ONLY MODEST
SUSTAINED UPDRAFT ROTATION GIVEN WEAK THERMODYNAMIC PROFILES.
STRONGER STORMS MAY POSE A RISK FOR A BRIEF TORNADO AS THEY MOVE EWD
AND INTERACT WITH THE WARM FRONT OR SEA BREEZE. TENDENCY HAS BEEN
FOR WINDS IN THE 0-2 KM LAYER TO WEAKEN AS THE MODEST LLJ SHIFTS
NEWD AND AWAY FROM THE UNSTABLE WARMS SECTOR IN ASSOCIATION WITH A
PROGRESSIVE SHORTWAVE TROUGH.

..DIAL/HART.. 05/13/2012

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

ATTN...WFO...TAE...

LAT...LON 31148599 30438527 30128526 30088554 30318604 30578629
30868631 31148599

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