http://www.spc.noaa.gov/products/DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM CDT SUN APR 12 2009
VALID 121630Z - 131200Z
...THERE IS A MDT RISK OF SVR TSTMS FROM SE TX INTO PART OF LA AND
MS...
...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
FROM CNTRL TX INTO PARTS OF OK/AR AND THE LWR MS VLY...
...SYNOPSIS...
UPPER LOW CURRENTLY OK/TX PANHANDLE AREA MOVES ENEWD TO SERN KS BY
12Z MON. VERY STRONG MID/UPPER JET SRN/CNTRL TX ROTATES EWD INTO
LOWER MS VALLEY OVERNIGHT IN CONCERT WITH TROUGH TO S OF UPPER LOW
WHICH BECOMES NEGATIVELY TILTED ALONG WITH INCREASING DIFFLUENCE.
SFC LOW ALONG FRONTAL ZONE ERN TX DEVELOPS NEWD ACROSS ERN AR BY
THIS EVENING AS COLD FRONT CONTINUES TO PUSH EWD ACROSS LOW MS
VALLEY AT THE SAME TIME. STRONG INFLUX OF MOIST/UNSTABLE GULF AIR
UNDERWAY AHEAD OF COLD FRONT WITH THE PRIMARY QUESTION TODAY BEING
THE QUALITY OF THE WARM SECTOR AIR MASS THAT CAN DEVELOP PRIOR TO
PASSAGE OF THE FORCED LINE OF THUNDERSTORMS NOW ALONG THE COLD
FRONT.
GIVEN THE STRENGTH OF THE SHEAR PROFILES SUPPORTIVE OF BOTH QLCS AND
SUPERCELL MODE OF CONVECTION AND POTENTIAL FOR SUFFICIENT ADVECTION
OF BOUNDARY LAYER GULF AIR HAVE EXTENDED HAVE EXTENDED THE MDT RISK
A LITTLE FURTHER INTO LWR MS VALLEY FOR LATER THIS
AFTERNOON/EVENING.
...SE TX INTO LOWER MS VALLEY...
COMBINATION OF MODEST SFC HEATING AND CONTINUED MOISTURE INFLOW HAS
ALREADY DESTABILIZED REGION TO ALLOW EXISTING ELEVATED
SHOWERS/STORMS NOW OVER SE TX AND THE NWRN GULF TO BECOME NEARLY
SFC-BASED BY LATE THIS MORNING. OTHER NEAR-SFC-BASED STORMS MAY
FORM BY EARLY AFTN INVOF WARM FRONT OVER SRN LA. AT THE SAME
TIME...SOME SFC HEATING AND EWD PROGRESSION OF HEIGHT FALLS WITH
APPROACHING UPR VORT HAS SUPPORTED STRENGTHENING OF STORMS WITHIN
SRN END OF SQLN NOW OVER ERN TX MOVING INTO NWRN LA. FARTHER
N...SCTD ELEVATED STORMS WITH HAIL MAY SPREAD NWD WITH 850 MB WARM
FRONT ACROSS PARTS OF NRN LA...AR AND MS.
WIND PROFILES ACROSS SE TX AND LA WILL BE VERY FAVORABLE FOR
SUSTAINED SUPERCELLS...WITH 40+ KT SLY LLJ VEERING TO 60+ KT SW FLOW
AT 500 MB THIS AFTERNOON. COUPLED WITH INCREASING MOISTURE AND UPR
DIFFLUENCE N OF SUBTROPICAL JET...SETUP COULD YIELD A FEW STRONG
TORNADOES...IN ADDITION TO SVR HAIL/WIND. QUESTIONS DO REMAIN
REGARDING OVERALL DEGREE OF SVR THREAT GIVEN /1/ PRESENCE OF EML CAP
THAT COULD LIMIT POTENTIAL FOR WAA STORMS TO BECOME
SUSTAINED/SFC-BASED...AND /2/ LIKELY PREDOMINANTLY LINEAR MODE OF
CONVECTION ALONG AFOREMENTIONED SQLN. NEVERTHELESS...GIVEN THE
POSSIBILITY FOR AT LEAST STRONG EMBEDDED SUPERCELLS FROM SE TX INTO
PARTS OF LA AND SRN/WRN MS...THE MDT RISK IS MAINTAINED AND SHIFTED
A LITTLE N IN MS/NERN LA
HIGH RES MODELS SUGGEST A MATURE QLCS WILL QUICKLY CROSS MS EARLY
TONIGHT WITH THE POTENTIAL FOR DAMAGING WINDS AT LEAST INTO WRN AL
PRIOR TO WEAKENING DUE TO DIMINISHING WARM SECTOR INSTABILITY.
...N TX/SRN OK...
BEHIND THE INITIAL BAND RAIN/TSTMS OVER CNTRL TX/OK...A SEPARATE
AREA OF STORMS MAY FORM BENEATH UPR LOW DRY SLOT AS IT CROSSES THE
RED RVR VLY. HEATING BENEATH MID LVL COLD POOL SHOULD YIELD 500 TO
1000 J/KG SBCAPE BY LATE IN THE DAY. WITH AMPLE LARGELY
UNIDIRECTIONAL DEEP WLY SHEAR OVER THE RED RVR VLY AREA S OF UPR
LOW...A FEW STRONG/ORGANIZED STORMS MAY PRODUCE HAIL AND/OR LOCALLY
DMGG WIND. THE STORMS SHOULD WEAKEN AFTER SUNSET.
..HALES/SMITH.. 04/12/2009
Gruss
in etwa 30 Min.
