DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0700 AM CST THU MAR 08 2012
VALID 081300Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS THROUGH THIS EVENING FROM
CENTRAL TX TO THE ARKLAMISS...
...SYNOPSIS...
THE CLOSED MIDLEVEL LOW ALONG THE NM/AZ BORDER THIS MORNING WILL
DRIFT EWD INTO NM TODAY AND BECOME QUASI-STATIONARY BY TONIGHT...AS
A STRONG NRN STREAM PROGRESSES EWD OVER THE GREAT LAKES TOWARD NEW
ENGLAND. IN THE WAKE OF THE AFOREMENTIONED NRN STREAM TROUGH...A
SURFACE COLD FRONT NOW LOCATED FROM SRN LOWER MI TO STL TO SPS WILL
MOVE SEWD TO THE I-20 CORRIDOR TONIGHT. AN INFLUX OF LOW-MID 60S
BOUNDARY LAYER DEWPOINTS INTO THE FRONTAL ZONE HAS SUPPORTED
MULTIPLE CLUSTERS OF ELEVATED STORMS NEAR AND N OF THE FRONT FROM
THE SRN PLAINS TO THE LOWER OH VALLEY. THE PRONOUNCED WARM SECTOR
CAP OF PREVIOUS DAYS WILL WEAKEN TODAY AS A RESULT OF ASCENT...WHICH
WILL SUPPORT RELATIVELY WIDESPREAD CONVECTION NEAR AND N OF THE
BOUNDARY INTO TONIGHT.
12Z SOUNDINGS...SURFACE ANALYSES...AND LOW-LEVEL TRAJECTORIES ALL
SUGGEST THAT THE STRONGER INSTABILITY WILL BE CONFINED TO MS WWD
INTO TX BY THIS AFTERNOON. MLCAPE IS EXPECTED TO INCREASE TO
1500-2000 J/KG AS SURFACE TEMPERATURES WARM INTO THE MID-UPPER 70S S
OF THE COLD FRONT...WHICH WILL SUPPORT STRONG UPDRAFTS.
MEANWHILE...A 35-50 KT SLY/SWLY LLJ FROM E TX TO THE CONFLUENCE OF
THE MS/OH RIVERS AS OF 12Z WILL SLOWLY WEAKEN BY LATE TODAY...AS THE
INFLUENCE OF THE NRN STREAM TROUGH DIMINISHES. THE NET RESULT WILL
BE WEAKENING LOW-LEVEL SHEAR IN THE WARM SECTOR WITH TIME...AND THE
STRONGER MIDLEVEL FLOW IS EXPECTED TO REMAIN ON THE COOL SIDE OF THE
FRONT. THUS...THE PHASING OF VERTICAL SHEAR AND INSTABILITY IS
RATHER POOR IN THE WARM SECTOR...WHICH SUGGESTS THAT THE SEVERE
STORM THREATS WILL BE ISOLATED LARGE HAIL AND DAMAGING WINDS WITH
CLUSTERS/LINE SEGMENTS IN AN ANAFRONTAL FLOW REGIME.
..THOMPSON/LEITMAN.. 03/08/2012
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