DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 051632
SWODY1
SPC AC 051630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1030 AM CST TUE MAR 05 2013

VALID 051630Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR ERN
AL...CENTRAL AND N GA...AND EXTREME WRN SC...

...SYNOPSIS...
A DEEP MIDLEVEL LOW OVER IA IS IN THE PROCESS OF PHASING WITH A
SEPARATE SRN STREAM SPEED MAX OVER NE TX. THE NE TX SPEED MAX WILL
TRANSLATE QUICKLY EWD TO THE SRN APPALACHIANS THIS EVENING...AND THE
UPSTREAM LOW WILL BEGIN A DEEPENING PROCESS TONIGHT. A SURFACE
CYCLONE INVOF WRN KY AS OF 15Z WILL DEEPEN AND OCCLUDE ACROSS SRN OH
TONIGHT...AS SECONDARY CYCLOGENESIS OCCURS IN THE LEE OF THE
APPALACHIANS ACROSS NC/VA. THE INLAND WARM/MOIST SECTOR WILL NOT BE
LARGE TODAY...BUT SUFFICIENT DESTABILIZATION IS EXPECTED FROM AL
INTO PARTS OF GA/SC TO SUPPORT A RISK OF AT LEAST ISOLATED SEVERE
STORMS THIS AFTERNOON/EVENING.

...ERN AL/CENTRAL AND N GA/WRN SC THIS AFTERNOON AND EVENING...
BOUNDARY LAYER DEWPOINTS OF 55-60 F ARE SPREADING NEWD IN ADVANCE OF
THE COLD FRONT CROSSING THE ARKLAMISS...AND BENEATH STEEP MIDLEVEL
LAPSE RATES PER 12Z SOUNDINGS. THE LAPSE RATE PLUME IS RELATIVELY
WARM COMPARED TO THE MAGNITUDE OF THE MOISTURE...AND THIS WILL TEND
TO LIMIT THE MAGNITUDE OF BUOYANCY THROUGH THE PERIOD.
ALSO...WIDESPREAD CLOUDS WILL SLOW SURFACE HEATING...AND THE CAP
ASSOCIATED WITH THE STEEP LAPSE RATES WILL INHIBIT SURFACE-BASED
THUNDERSTORM DEVELOPMENT UNTIL MID-LATE AFTERNOON WHEN THE MID 50S
DEWPOINTS REACH CENTRAL AL/GA. THUNDERSTORM DEVELOPMENT WILL BECOME
INCREASINGLY PROBABLE ALONG THE COLD FRONT IN THE 21-00Z TIME FRAME
ACROSS ERN AL AND CENTRAL/N GA...WHEN ASCENT ALONG THE FRONT WILL
COINCIDE WITH MLCAPE OF 250-500 J/KG AND SOME WEAKENING OF
CONVECTIVE INHIBITION. THOUGH INSTABILITY WILL BE MARGINAL...STRONG
DEEP-LAYER WIND PROFILES WILL SUPPORT A RISK FOR DAMAGING WINDS WITH
LINE SEGMENTS AND EMBEDDED CELLS NEAR THE COLD FRONT. LOW-LEVEL
SHEAR WILL BE STRONGER FROM CENTRAL/N GA TO THE SAVANNAH RIVER
VALLEY THIS EVENING...WHERE AN ISOLATED SPINUP WILL BE POSSIBLE
PRIOR TO THE CONVECTION EXHAUSTING THE LIMITED INSTABILITY.

..THOMPSON/DIAL.. 03/05/2013

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