SWODY1
SPC AC 210453
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1153 PM CDT FRI APR 20 2012
VALID 211200Z - 221200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE CNTRL AND SRN FL
PENINSULA...
...SYNOPSIS...
SYNOPTIC TROUGH WILL CONTINUE TO EVOLVE ACROSS THE ERN THIRD OF THE
COUNTRY SATURDAY. A SRN STREAM SHORTWAVE TROUGH IS IN THE PROCESS OF
CUTTING OFF FROM NRN BRANCH AND WILL MOVE THROUGH THE GULF OF MEXICO
DURING THE DAY...REACHING THE FL PENINSULA SATURDAY NIGHT. A COLD
FRONT EXTENDING FROM A WEAK SFC LOW OVER THE NERN U.S. SWWD TO A
WEAK LOW OVER THE NWRN GULF EARLY SATURDAY WILL ADVANCE EWD DURING
THE PERIOD. BY EARLY SATURDAY EVENING THIS BOUNDARY WILL EXTEND FROM
THE ATLANTIC SEABOARD SWWD TO A SFC LOW OVER THE NERN GULF.
...CNTRL AND SRN FL...
AS OF FRIDAY EVENING NUMEROUS THUNDERSTORMS ARE IN PROGRESS OVER THE
ERN GULF AND WRN FL COAST IN ASSOCIATION WITH A LEAD IMPULSE. OTHER
THUNDERSTORMS ARE INCREASING ACROSS THE WRN GULF AS ZONE OF DEEPER
FORCING FOR ASCENT INTERACTS WITH THE UNSTABLE AIR IN THIS REGION.
NUMEROUS STORMS WILL CONTINUE TO DEVELOP THROUGH THE GULF
SATURDAY...EVOLVING INTO AN MCS WITH CLUSTERS AND BANDS OF STORMS
ADVANCING EWD AND LIKELY AFFECTING THE FL PENINSULA. GIVEN THE
WIDESPREAD NATURE OF CLOUDS AND PRECIPITATION...INSTABILITY AND
LAPSE RATES SHOULD REMAIN MARGINAL WITH MLCAPE LIKELY BELOW 1000
J/KG WHICH COULD SERVE AS AN OVERALL LIMITING FACTOR FOR A GREATER
SEVERE THREAT. NEVERTHELESS...SOME POTENTIAL FOR SEVERE STORMS WILL
EXIST MAINLY FROM EVENING INTO THE OVERNIGHT AS LLJ AND FLOW ALOFT
STRENGTHEN IN ASSOCIATION WITH THE APPROACHING UPPER TROUGH. DEEP
LAYER SHEAR INCREASING TO 40 KT AND 0-2 KM HODOGRAPHS WILL GRADUALLY
BECOME MORE FAVORABLE FOR A FEW ORGANIZED STORMS INCLUDING THE
POTENTIAL FOR SUPERCELLS AND BOWING SEGMENTS INTO THE EVENING. MAIN
THREATS WILL BE ISOLATED DAMAGING WIND AND PERHAPS ISOLATED
TORNADOES.
...MID ATLANTIC REGION...
POOR MID LEVEL LAPSE RATES AND MODEST LOW LEVEL MOISTURE WILL YIELD
ONLY MARGINAL INSTABILITY IN PRE-FRONTAL WARM SECTOR OVER THE MID
ATLANTIC REGION. A FEW STORMS WILL LIKELY DEVELOP IN VICINITY OF THE
FRONT. VERTICAL SHEAR AOB 35 KT WILL SUPPORT MULTICELLS. DIABATIC
WARMING WILL STEEPEN LOW LEVEL LAPSE RATES AND ISOLATED STORMS MAY
BECOME CAPABLE OF PRODUCING STRONG WIND GUSTS...BUT OVERALL THREAT
IS EXPECTED TO REMAIN LIMITED.
..DIAL/SMITH.. 04/21/2012
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