SPC AC 291629
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT TUE MAR 29 2011
VALID 291630Z - 301200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTH-CENTRAL/SOUTHEAST
TX TO LOWER MS VALLEY/CENTRAL GULF COAST...
...SOUTH TX/TX COASTAL PLAIN TO LOWER MS VALLEY/CENTRAL GULF
COAST...
WATER VAPOR IMAGERY REFLECTS A MODESTLY AMPLIFYING LONGWAVE TROUGH
OVER THE CENTRAL CONUS...WITH AN EMBEDDED SHORTWAVE TROUGH SPREADING
EASTWARD OVER THE CENTRAL HIGH PLAINS AT MIDDAY. THERE ALSO APPEARS
TO BE ONE OR MORE SUBTLE/LOW AMPLITUDE IMPULSES EMBEDDED WITHIN A
SUBTROPICAL STREAM ACROSS NORTHERN MEXICO...WHICH IS EXPECTED TO AID
HIGHER LEVEL DIVERGENCE AS IT SPREADS EASTWARD ACROSS THE SOUTHERN
PLAINS/LOWER MS VALLEY BY THIS EVENING. AN OLD FRONTAL BOUNDARY
OFFSHORE WILL RETREAT NORTHWARD AS A WARM FRONT TODAY ACROSS
SOUTHEAST TX AND THE LOWER MS RIVER VALLEY...AHEAD OF A POLAR FRONT
CROSSING EAST/SOUTH TX.
A PRONOUNCED ELEVATED MIXED LAYER WITH MID LEVEL LAPSE RATES OF 8
C/KM OR GREATER COVERS ALL OF THE SOUTHERN PLAINS EASTWARD TO THE MS
RIVER. CURRENT CLOUD COVER ACROSS THE WARM SECTOR WILL GIVE WAY/THIN
THROUGH THE AFTERNOON...AS AMPLE HEATING COMBINED WITH SURFACE
DEWPOINTS INCREASING INTO THE UPPER 60S/LOWER 70S F CONTRIBUTES TO
MODERATE SURFACE BASED BUOYANCY THIS AFTERNOON /1500-2500 J PER KG
MLCAPE/. AT THIS TIME...IT APPEARS THE RELATIVELY STRONGEST
DESTABILIZATION WILL OCCUR ACROSS THE SOUTH-CENTRAL TX/RIO GRANDE
VICINITY...AND PERHAPS SOUTHERN LA.
IT APPEARS THAT THE AFOREMENTIONED STRONG EML/STOUT CAP WILL TEND TO
GENERALLY LIMIT WARM SECTOR DEEP CONVECTIVE DEVELOPMENT...WITH
SCATTERED TSTMS MOST LIKELY TO FORM LATE THIS AFTERNOON/EVENING IN
VICINITY OF THE SOUTHEAST ADVANCING POLAR FRONT ACROSS
SOUTH-CENTRAL/SOUTHEAST TX...AS WELL AS NEAR THE WARM FRONT ACROSS
THE LOWER MS VALLEY.
THE PRIMARY SEVERE THREATS WILL BE LARGE HAIL AND WIND DAMAGE AS
STORMS EVOLVE INTO SHORT LINE SEGMENTS AS THEY MOVE
EAST-SOUTHEASTWARD ACROSS SOUTHEAST TX AND THE SOUTHERN HALVES OF
LA/MS. SUPERCELLS ARE POSSIBLE...PARTICULARLY NEAR THE WARM FRONT
WHERE MODESTLY ENHANCED LOW LEVEL SHEAR WILL SUPPORT A RISK OF
TORNADOES. BUT OTHERWISE...RELATIVELY WEAK WIND SPEEDS IN THE LOWER
TROPOSPHERE WILL TEND TO LIMIT A TORNADO THREAT.
..GUYER/ROGERS.. 03/29/2011
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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