SWODY1
SPC AC 141950
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0250 PM CDT SAT APR 14 2007
VALID 142000Z - 151200Z
..THERE IS A MDT RISK OF SVR TSTMS FROM SOUTHEAST MS...ACROSS
SOUTHERN AND CENTRAL AL...THE WESTERN FL PANHANDLE...CENTRAL
GA...AND PARTS OF SC...
..THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL GULF COAST
REGION INTO THE MID ATLANTIC STATES...
..ACTIVE SEVERE WEATHER THREAT EVENT EVOLVING ACROSS CENTRAL/NERN
GULF COAST STATES THIS AFTERNOON/EVENING AND SPREADING INTO SERN
STATES TONIGHT...
..SYNOPSIS...
UPPER TROUGH OVER SRN PLAINS WILL PHASE WITH NRN STREAM TROUGH FROM
THE GREAT LAKES TO LOWER MS VALLEY THIS FORECAST PERIOD...RESULTING
IN STRONG HEIGHT FALLS ACROSS THE TN VALLEY/GULF COAST STATES
THROUGH TONIGHT. AT THE SURFACE...ONE AREA OF LOW PRESSURE HAS
MOVED INTO NWRN TN WITH A WARM FRONT EXTENDING SEWD INTO NRN AL
THROUGH NWRN-ERN GA TO CENTRAL SC. A SECONDARY LOW HAD DEVELOPED
OVER SRN MS WITH A WARM FRONT EXTENDING EWD THROUGH CENTRAL AL TO
CENTRAL/SRN GA. THIS SECOND LOW AND SRN WARM FRONT SHOULD REMAIN
THE MAIN MESOSCALE/SYNOPTIC FEATURES AS FOCI FOR SEVERE STORM
ACTIVITY THROUGH THIS AFTERNOON/EVENING ACROSS AL INTO GA/SC.
..SERN MS/AL/FL PANHANDLE...
CLUSTER OF SUPERCELL STORMS ARE CURRENTLY AFFECTING SW INTO SRN AL.
THESE STORMS ARE EXPECTED TO TRACK EASTWARD ACROSS SRN AL
THIS AFTERNOON ALONG RETREATING WARM FRONT WHERE LOW LEVEL VERTICAL
SHEAR PROFILES WILL REMAIN FAVORABLE FOR STRONG TO POTENTIALLY
LONG-LIVED TORNADOES. AREAS SOUTH OF THE WARM FRONT WILL CONTINUE
TO DESTABILIZE WITH CAPE VALUES OVER 1500 J/KG. SCATTERED TSTMS ARE
EXPECTED TO DEVELOP ACROSS THIS REGION TO THE S AND E OF ONGOING
CLUSTER OF SUPERCELLS...WITH PARAMETERS FAVORABLE FOR SUPERCELLS AND
A FEW TORNADOES. COMBINATION OF FAVORABLE CAPE AND SHEAR INDICATE A
RISK OF ISOLATED STRONG TORNADOES.
..GA/SC THIS EVENING THROUGH TONIGHT...
VISIBLE SATELLITE IMAGERY SHOWED HIGH CLOUDS STREAMING EWD ACROSS
THE NRN HALF OF GA FROM ONGOING UPSTREAM TSTM ACTIVITY. ADDITIONAL
SURFACE HEATING IS EXPECTED S OF THIS CLOUD SHIELD WHERE SURFACE
TEMPERATURES ARE ALREADY INTO THE MID-UPPER 80S. INFLUX OF RICH
GULF MOISTURE WILL PERSIST THIS FORECAST PERIOD ACROSS THE WARM
SECTOR AS THE WARM FRONT...NOW LOCATED OVER NRN AL INTO CENTRAL GA
AND CENTRAL SC...CONTINUES TO RETREAT NWD. CLUSTERS OF TSTMS WILL
LIKELY MOVE OUT OF AL THIS AFTERNOON AND ACROSS GA THIS EVENING...
AND INTO SC OVERNIGHT. IN ADDITION... VISIBLE IMAGERY/REGIONAL
RADARS INDICATED CU INCREASING IN COVERAGE AND FEW TSTMS TRYING TO
DEVELOP ACROSS SWRN GA WHERE AIR MASS WILL UNDERGO FURTHER
DESTABILIZATION.
RAPID DEEPENING OF SURFACE LOW THIS FORECAST PERIOD WILL RESULT IN
EXTREMELY STRONG LOW LEVEL VERTICAL SHEAR PROFILES ACROSS THIS
REGION AFTER DARK. POTENTIAL WILL EXIST FOR TORNADIC SUPERCELLS
ACROSS THE MDT RISK AREA...ALONG WITH ISOLATED STRONG TORNADOES.
UPSCALE ORGANIZATION IS ALSO POSSIBLE ACROSS THIS REGION DURING THE
NIGHT WITH A DAMAGING WIND/TORNADO THREAT ALONG LEADING EDGE OF
SQUALL LINE.
..NC/VA AFTER MIDNIGHT...
SURFACE LOW IS FORECAST TO DEEPEN BELOW 998MB BY 12Z OVER SOUTHERN
VA. INTENSE WIND FIELDS IN THE WARM SECTOR OF THE LOW WILL MAINTAIN
A RISK OF DAMAGING WINDS AND TORNADOES WITH ORGANIZED CONVECTION
OVER THIS REGION.
.PETERS.. 04/14/2007
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