SWODY1
SPC AC 310544
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1144 PM CST WED JAN 30 2008
VALID 311200Z - 011200Z
..THERE IS A SLGT RISK OF SVR TSTMS TODAY THRU TONIGHT ACROSS PARTS
OF THE GULF COAST STATES....
..SYNOPSIS...
MODELS INDICATE THAT THE VIGOROUS SHORT WAVE TROUGH...NOW DIGGING
INTO THE CENTRAL/SOUTHERN PLAINS...WILL REMAIN PROGRESSIVE DURING
THIS FORECAST PERIOD. THE SYSTEM IS EMBEDDED WITHIN A STRONG BELT
OF POLAR WESTERLIES EMANATING FROM THE NORTHERN PACIFIC. AND...
ANOTHER BROADER TROUGH WITHIN THIS STREAM IS PROGGED TO MIGRATE
INLAND ACROSS THE PACIFIC NORTHWEST INTO THE NORTHERN INTERMOUNTAIN
REGION BY 12Z FRIDAY.
AFTER CONTINUING TO DIG THROUGH MID TO LATE MORNING...THE LEAD
IMPULSE IS PROGGED TO LIFT OUT OF THE SOUTHERN PLAINS...TAKING ON A
MORE NEUTRAL TO NEGATIVE TILT ACROSS THE MID/LOWER MISSISSIPPI
VALLEY LATER TODAY/TONIGHT. AS THIS OCCURS...STRONGLY DIFLUENT
UPPER FLOW WILL LIKELY DEVELOP AND SPREAD ACROSS THE CENTRAL GULF
STATES...BETWEEN THE BASE OF THE TROUGH AND A WEAKER BRANCH OF
WESTERLIES EMANATING FROM THE SUBTROPICAL PACIFIC.
WHILE SOME INTERACTION/PHASING OF THE TWO STREAMS APPEARS
LIKELY...THE EXTENT TO WHICH THIS OCCURS IS A SOURCE OF
UNCERTAINTY/VARIABILITY AMONG THE MODELS. THE BULK OF GUIDANCE
CONTINUES TO SUGGEST THAT SURFACE CYCLOGENESIS WILL BE RELATIVELY
WEAK IN THE WAKE OF THE RECENT STRONG COLD INTRUSION. THE PRIMARY
SURFACE LOW CENTER MAY SLOWLY ORGANIZE OUT OF A DEVELOPING WAVE OVER
EASTERN TEXAS EARLY IN THE PERIOD...BEFORE LIFTING NORTHEASTWARD
INTO THE LOWER OHIO VALLEY BY 12Z FRIDAY. BUT...PERHAPS OF MORE
SIGNIFICANCE...MODELS HAVE INDICATED THE DEVELOPMENT OF A WEAKER
SECONDARY WAVE AHEAD OF THE COLD FRONT SURGING TO THE SOUTH OF THE
MAIN LOW. THIS IS EXPECTED TO FORM ALONG A WARM FRONTAL ZONE
MARKING THE RETURN OF A MOISTENING BOUNDARY LAYER OFF THE GULF OF
MEXICO...AND PROBABLY WILL PROVIDE THE MAIN FOCUS FOR ANY SEVERE
THUNDERSTORM ACTIVITY TODAY/TONIGHT.
..GULF STATES...
LARGE LOW-LEVEL HODOGRAPHS AND STRONG DEEP LAYER SHEAR WILL EXIST
ACROSS MUCH OF THE SOUTH CENTRAL AND SOUTHEASTERN STATES TODAY.
BUT...MUCH OF THIS WILL GO UNREALIZED WITH A DRY COLD BOUNDARY LAYER
SLOW TO MODIFY. THE BULK OF CONVECTIVE DEVELOPMENT LIKELY TO FORM
AHEAD OF APPROACHING SHORT WAVE TROUGH IS EXPECTED TO BE BASED IN
MOISTURE RETURN ABOVE THIS LAYER...WITH WEAK INSTABILITY MINIMIZING
SEVERE POTENTIAL.
HOWEVER...BOUNDARY LAYER MOISTENING INLAND OF COASTAL AREAS IS
EXPECTED TO OCCUR...ACROSS PARTS OF UPPER TEXAS AND LOUISIANA
COASTAL AREAS EARLY TODAY...EASTWARD ACROSS CENTRAL/EASTERN GULF
COASTAL AREAS LATER TODAY AND TONIGHT. JUST HOW FAR INLAND IS STILL
UNCLEAR...BUT IT SEEMS PROBABLE THAT THE COASTAL FRONT WILL SPREAD
NORTH OF MUCH OF SOUTHERN LOUISIANA/MISSISSIPPI AND SOUTHWEST
ALABAMA DURING THE DAYTIME HOURS...WHEN INSOLATION WILL CONTRIBUTE
TO DESTABILIZATION.
MIXED LAYER CAPE COULD APPROACH OR EXCEED 1000 J/KG. AND...IN
CONJUNCTION WITH FORCING/SHEAR NEAR FRONTAL WAVE...THIS IS EXPECTED
TO BECOME SUPPORTIVE OF SUPERCELL DEVELOPMENT WITH POTENTIAL FOR
TORNADOES/LOCALIZED DAMAGING WIND GUSTS AND LARGE HAIL. ISOLATED
STRONG TORNADOES ARE POSSIBLE THIS AFTERNOON AND EVENING. AND...AT
LEAST A LOCALIZED THREAT COULD CONTINUE NEAR THE WAVE AS IT TRACKS
ACROSS THE REMAINDER OF SOUTHERN ALABAMA/THE FLORIDA PANHANDLE AND
SOUTHWEST GEORGIA LATER THIS EVENING/ OVERNIGHT.
.KERR.. 01/31/2008
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