SPC AC 161955
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0155 PM CST SAT FEB 16 2008
VALID 162000Z - 171200Z
...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF ERN TX INTO WRN
LA...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF TX ACROSS THE
LOWER MS RIVER VALLEY...
...SRN PLNS TO LWR MS VLY...
19Z SFC ANALYSIS PLACES A FRONT FROM JUST E OF THE DFW METROPLEX SWD
ALONG THE ESCARPMENT...THEN SWD INTO S TX. COLD AIR HAS SLOWED EWD
SEEPAGE OWING TO DEVELOPMENT OF A SFC LOW NEAR KSAT. THIS LOW WILL
MIGRATE NWD ALONG THE BOUNDARY INTO NCNTRL/NERN TX BY THIS EVENING
TOWARD A REGION OF INCREASING PRESSURE FALLS. AS A RESULT...
RESIDENT LOW-LEVEL MOISTURE OVER SERN TX WILL ADVECT NWD INTO THE
ARKLATEX REGION WITH THE LOW-LEVEL STABLE LAYER...EVIDENT ON THE 18Z
SHV RAOB...ERODING WITH TIME INTO THE ARKLATEX REGION.
VSBL SATL PICTURE PORTRAYS PLENTY OF CLOUD COVER IN THE PRE-FRONTAL
WARM SECTOR WITH SHALLOW CONVECTION DEVELOPING BENEATH A STOUT CAP
AS NOTED ON THE RECENT CRP RAOB. THIS CAP IS LIKELY WEAKER FARTHER
N IN THE KIAH REGION PER ACARS...BUT LACK OF ROBUST SFC HEATING IS
PROBLEMATIC. NONETHELESS...THE CAP WILL GRADUALLY ERODE AS ASCENT
ASSOCD WITH THE W TX UPR LOW ARRIVES LATER THIS AFTN. THIS WILL
RELEASE THE BUILDING INSTABILITY AND CONTRIBUTE TO DEEPENING
CONVECTION ALONG/E OF THE FRONT FROM SERN OK SWD INTO SCNTRL TX.
PRIMARY SVR CONCERN THROUGH ABOUT 21Z WILL BE FOR ELEVATED TSTMS AND
LARGE HAIL RISKS ATOP THE COLD DOME FROM SWRN/SCNTRL OK INTO THE BIG
COUNTRY/HILL COUNTRY REGIONS OF NCNTRL TX. FWD SOUNDING EXHIBITED A
7.2 DEG C PER KM MID-LVL LAPSE RATE AND MUCAPE OF NEARLY 2000 J PER
KG. INCREASING EFFECTIVE SHEAR THROUGH THE AFTN WILL BE FAVORABLE
FOR ELEVATED SUPERCELLS.
HIGHER SVR POTENTIAL WILL DEVELOP AFTER ABOUT 21Z AS PRE-FRONTAL
SFC-BASED TSTMS ARE EXPECTED TO STRENGTHEN ACROSS ERN/SERN TX. PAT
PROFILER AND FCST HODOGRAPHS INDICATE 0-1KM SRH IN EXCESS OF 250
M2/S2 AND 6KM SHEAR OF 45-50 KTS...INDICATIVE OF SUPERCELLS. GIVEN
THE LOW LCL/S IN PLACE AND PROSPECTS FOR DISCRETE CELLS...RISKS FOR
A COUPLE OF STRONG TORNADOES WILL CONTINUE ACROSS PORTIONS OF
SCNTRL/SERN TX/UPR TX COAST. AGAIN...PRIMARY PROBLEM WILL BE IF THE
WARM SECTOR CAN DESTABILIZE SUFFICIENTLY TO SUPPORT VIGOROUS
UPDRAFTS AND EVENTUAL ROOTING INTO THE BOUNDARY LAYER.
OTHERWISE...ASIDE FROM THE DISCRETE STORM POSSIBILITIES...IT IS MUCH
MORE CERTAIN THAT A STRONGLY FORCED SQUALL LINE WILL EVOLVE ALONG
THE COLD FRONT...GRADUALLY BUILDING SWWD INTO THE STRONGER CAP INTO
SCNTRL TX. DMGG WIND GUSTS WILL BE QUITE LIKELY AS THE LINE
ACCELERATES INTO SERN TX AND THE SABINE RVR VLY. NRN EXTENT OF THE
LINE N OF THE ARKLATEX WILL BE ROOTED ATOP A RESIDUAL STABLE LAYER
WITH DECREASING SVR THREATS AT MORE NLY LATITUDES. SRN EDGE OF THE
LINE WILL MAINTAIN THE RISKS FOR TORNADOES AND DMGG WIND GUSTS INTO
SRN/CNTRL LA THROUGH 12Z.
..RACY.. 02/16/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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