SWODY2
SPC AC 191731
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1231 PM CDT MON MAR 19 2012
VALID 201200Z - 211200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER SOUTHEAST TEXAS....THE
ARKLATEX REGION AND OZARKS...
...SYNOPSIS...
HIGH AMPLITUDE FLOW REGIME WILL FEATURE AN ANOMALOUSLY DEEP CYCLONE
SITUATED OVER THE SOUTHWEST AND SRN HIGH PLAINS AND AN EXTENSIVE AND
JUST AS ANOMALOUS UPPER RIDGE AXIS OVER THE ERN 1/3RD OF NORTH
AMERICA. BETWEEN THESE TWO LARGE SCALE ANOMALIES WILL EXIST ANOTHER
ANOMALY...HIGH AMOUNTS OF ATMOSPHERIC WATER VAPOR BEING TRANSPORTED
NWD FROM THE SUB-TROPICS ACROSS THE NWRN GULF COAST AND INTO THE
CNTRL CONUS. GIVEN THE LARGE SCALE BLOCKING...EVOLVING DEEP-LAYER
CLOSED LOW FORECAST TO TAKE FORM IN THE BASE OF THE LARGE SCALE
TROUGH OVER THE SOUTHWEST WILL MAKE ONLY VERY SLOW EWD PROGRESS THIS
PERIOD. AS ALLUDED IN PREVIOUS DY2 OUTLOOK...MODELS CONTINUE TO
TREND SLOWER IN THE EWD PROGRESSION OF THE LOW THROUGH EARLY WED.
...SERN TX/ARKLATEX TO OZARKS...
LIFT ALONG LEADING EDGE OF HEIGHT FALLS ASSOCIATED WITH THE SLOWLY
ADVANCING DEEP-LAYER CYCLONE WILL CONTINUE TO OCCUR COINCIDENT WITH
AN UNUSUALLY WARM AND MOIST AIRMASS. THIS SHOULD SUSTAIN PERSISTENT
DEEP CONVECTION IN ORGANIZED LINEAR BANDS..AND OCCASIONAL LARGER
CLUSTERS...ACROSS ERN TX THROUGH TONIGHT. MODEL GUIDANCE CONTINUES
TO TREND WWD WITH THE PLACEMENT OF THE STRONGEST MCS SIGNAL INTO
EARLY TUESDAY WITH LATEST INDICATIONS SUGGESTING THE CORRIDOR FOR
GREATEST TSTM POTENTIAL AT THE BEGINNING OF THIS FORECAST PERIOD
FROM SOUTHEAST TX ACROSS ERN OK TO SWRN AR. ANAFRONTAL
CHARACTERISTICS TO THIS SYSTEM WILL BE SUPPORTED BY 1) THE SLOW EWD
MOVEMENT OF THE UPPER SYSTEM...AND 2) DEEP-LAYER MERIDIONAL FLOW.
AHEAD OF THE LINEAR MCS ANTICIPATED ACROSS SERN TX AND ERN
OK...SHEAR AND INSTABILITY EAST ACROSS THE WARM/MOIST SECTOR WILL
REMAIN MORE THAN ADEQUATE FOR ORGANIZED/SEVERE STORMS.
HOWEVER...WITH LIFT ESSENTIALLY FOCUSED NEAR THE LEADING EDGE OF THE
CONVECTIVE SYSTEM...OVERALL STORM EVOLUTION AND SEVERE THREAT
THROUGH THE DAY REMAINS SOMEWHAT UNCERTAIN IN BOTH ERN AND NRN
EXTENT.
MESOSCALE GUIDANCE HINTS AS SMALLER SCALE WAVES OF LOW PRESSURE
DEVELOPING AMIDST THE CONVECTIVE SYSTEM THROUGH THE MORNING AND INTO
THE AFTERNOON. FORECAST SHEAR PROFILES NEAR THESE WEAK DISTURBANCES
REVEAL SUBSTANTIAL ENVIRONMENTAL EFFECTIVE HELICITY ON THE ORDER OF
200-300 M2/S2 AND...WHEN COMBINED WITH THE HIGH MOISTURE AND LOW LFC
LIKELY WITHIN THE SLGT RISK CORRIDOR...THIS SUGGESTS THAT A COUPLE
OF TORNADOES SEEM POSSIBLE.
AS IS USUALLY THE CASE WITH REPEAT/TRAINING CONVECTION OF THIS
NATURE...STORM SCALE INTERACTIONS AND CAPE/INSTABILITY VARIATIONS
INTRODUCE CONSIDERABLE UNCERTAINTY AT THIS FORECAST RANGE. THERE
DOES APPEAR TO BE SOME CHANCE FOR A STRONG TORNADO IN THIS
ENVIRONMENT. HOWEVER...ATTEMPTING TO HIGHLIGHT A GREATER RISK AT
THIS TIME IS NOT LIKELY TO PROVE ACCURATE. WILL AWAIT ADDITIONAL
INFORMATION AND A HIGHER PROBABILITY TORNADO AREA MAY BE INCLUDED IN
AN UPCOMING DY1 OUTLOOK.
...TX PNHDL/SWRN OK/NWRN TX...
AS THE LARGER SYSTEM BECOME OCCLUDED AND COLD CORE PIVOTS ACROSS
NRN TX AND OK COINCIDENT WITH SOME POTENTIAL FOR SURFACE
HEATING...IT SEEMS REASONABLE TO EXPECT LOW-TOPPED CONVECTION WITH
SOME HAIL AND GUSTY WIND POTENTIAL IN THESE AREAS.
..CARBIN.. 03/19/2012
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