[font=tahoma]DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT MON MAR 19 2012
VALID 191200Z - 201200Z
...THERE IS A MDT RISK OF SVR TSTMS OVER MUCH OF CNTRL AND NERN TX
INTO FAR SERN OK...
...THERE IS A SLGT RISK OF SVR TSTMS FOR MUCH OF THE SRN PLAINS NWD
INTO THE MID MO RIVER VALLEY...
...SYNOPSIS...
AN EXPANSIVE FULL LATITUDE UPPER TROUGH WILL OVERSPREAD THE SRN AND
CNTRL PLAINS ON MONDAY WITH MERIDIONAL STYLE FLOW REGIME. SLY LOW
LEVEL FLOW WILL PERSIST THROUGHOUT THE PERIOD AHEAD OF A COLD
FRONT...RESULTING IN AMPLE MOISTURE AND INSTABILITY FOR WIDESPREAD
THUNDERSTORMS FROM TX INTO MN AND WI. THIS FRONT IS FORECAST TO
EXTEND FROM WRN/CNTRL OK INTO WRN N TX EARLY MON...BUT SHOULD STALL
ACROSS CNTRL TX.
MULTIPLE EPISODES OF SEVERE THUNDERSTORMS ARE EXPECTED ACROSS THE
SRN PLAINS...AND THERE IS A WIDE VARIETY OF MODEL SOLUTIONS.
HOWEVER...IT APPEARS CONSENSUS IS FOR WIDESPREAD SEVERE STORMS
CENTERED OVER THE MDT RISK AREA...FROM CNTRL/NERN TX INTO SERN OK.
ELSEWHERE...A WEAK DISTURBANCE IS FORECAST TO REMAIN OVER
OH/PA/WV...WITH ISOLATED HAIL OR WIND POSSIBLE FROM DIURNALLY DRIVEN
STORMS.
...TX INTO OK AND THE ARKLATEX REGION...
A COMPLICATED CONVECTIVE DAY WILL UNFOLD ON MONDAY. UNCERTAINTIES
BEGIN EARLY IN THE MORNING IN RELATION TO WHERE A SQUALL LINE...NOW
OVER WRN TX...WILL BE LOCATED...AND HOW MUCH COLD POOL AND
STABILIZATION WILL OCCUR WITH THIS SYSTEM. MODELS GENERALLY SUGGEST
THIS LINE WILL BE OVER W CNTRL OK INTO WRN N TX AT 12Z...WITH SRN
END NEAR I-20. THIS ACTIVITY WILL BE IN A STRONGLY SHEARED
ENVIRONMENT...AND STRONG TO SEVERE WINDS WILL BE POSSIBLE IN
ADDITION TO SOME HAIL. THIS ACTIVITY MAY REJUVENATE OVER ERN OK/NERN
TX WITH A STRONG 50 KT LOW LEVEL JET FEEDING INTO THAT AREA. LATER
IN THE AFTERNOON IN THIS SAME GENERAL VICINITY...ADDITIONAL
DEVELOPMENT FUELED BY WARM ADVECTION MAY OCCUR WITH CONVECTION
ALLOWING MODELS DEPICTING ISOLATED SUPERCELLS. SHEAR WOULD FAVOR
DAMAGING WINDS AND A FEW TORNADOES.
THE GREATEST SEVERE THREAT SHOULD BE DURING THE AFTERNOON AND INTO
THE EVENING OVER MUCH OF CNTRL TX. AS OF THIS WRITING...THIS AREA
SHOULD BE S OF THE MORNING ACTIVITY...AND ON THE INTERFACE OF STRONG
HEATING PROGGED OVER WRN/W CNTRL TX. FORECAST SOUNDINGS SHOW STEEP
LAPSE RATES ALOFT...STRONG INSTABILITY...AND AMPLE DEEP LAYER SHEAR
FOR SIGNIFICANT SEVERE WEATHER INCLUDING VERY LARGE HAIL...DAMAGING
WINDS AND TORNADOES. ISOLATED STRONG TORNADOES MAY OCCUR...BUT WILL
DEFER POSSIBLE SIGNIFICANT TORNADO PROBABILITIES TO LATER OUTLOOKS
GIVEN UNCERTAINTIES WITH LOW LEVEL FLOW AND BOUNDARY LOCATIONS.
CONVECTIVE COVERAGE WILL ONLY INCREASE OVERNIGHT WITH COUPLED JET
STRUCTURE ALOFT LIKELY RESULTING IN A LARGE MCS WITH SEVERE WEATHER
AND FLOODING RAIN.
...ERN KS...MO...NEB/IA...
UPPER 50S TO LOWER 60S F DEWPOINTS WILL STREAM NWD INTO THE MID MO
VALLEY WITH A 40+ KT SLY LOW LEVEL JET. LITTLE CIN WILL EXIST SO
WARM ADVECTION WILL BE SUFFICIENT TO DRIVE THUNDERSTORM DEVELOPMENT.
THIS WILL OCCUR IN A STRONGLY SHEARED ENVIRONMENT...AND SOME STORMS
MAY ACQUIRE ROTATION. A BRIEF TORNADO CANNOT BE RULED OUT...ALONG
WITH GUSTY WINDS.
...OH/WV INTO THE MID ATLANTIC REGION...
STRONG HEATING WILL OCCUR OVER THE REGION UNDER THE UPPER
RIDGE...BUT A POCKET OF MOISTURE ASSOCIATED WITH THE WEAK UPPER
WAVE/OLD MCV SHOULD HELP TO FOCUS SCATTERED THUNDERSTORMS DURING THE
DAY. ALTHOUGH SHEAR WILL BE WEAK...NWLY FLOW ALOFT AND STEEP LAPSE
RATES WILL FAVOR A FEW STORM CORES CAPABLE OF HAIL AND GUSTY WINDS.
..JEWELL/HURLBUT.. 03/19/2012[/font]
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