SWODY1
SPC AC 111609
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1109 AM CDT SUN MAR 11 2012
VALID 111630Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN TX/WRN-NRN LA INTO AR
AND SRN MO...
...ERN TX/WRN-NRN LA INTO AR AND SRN MO...
SATELLITE IMAGERY SHOWS AN UPPER LOW OVER THE NRN TX PANHANDLE
MOVING NEWD...AND THIS MOTION SHOULD CONTINUE THROUGH TONIGHT WITH
THE LOW REACHING NRN IA BY THE END OF THE PERIOD. THIS WILL OCCUR
AS A STRONG MID/UPPER LEVEL JET STREAK LIFTS NEWD FROM THE SRN
PLAINS ACROSS THE LOWER MO VALLEY. IN THE LOWER LEVELS...A MORE
DIFFUSE PATTERN WILL PERSIST AS A WEAK CONFLUENCE ZONE CURRENTLY
EVIDENT OVER ERN TX GRADUALLY SHIFTS EWD TO NEAR THE SABINE RIVER
INTO WRN AR BY LATE AFTERNOON/EVENING. WSR-88D VWP AND WIND
PROFILER DATA EXHIBIT STRONG SOUTHERLY WINDS ABOVE THE
SURFACE...RESULTING IN RAPID NWD MOISTURE TRANSPORT AND STRONG LOW
LEVEL SHEAR IN THE LOWEST 1-2 KM AGL. MODEL GUIDANCE SHOWS THE LOW
LEVEL JET WILL SPREAD NNEWD ACROSS AR TOWARD THE MIDDLE MS VALLEY
LATER THIS AFTERNOON AND TONIGHT IN ASSOCIATION WITH THE UPPER
LOW...WITH A CONTINUED NNEWD INCREASE IN MOISTURE.
LARGE SCALE ASCENT IN ADVANCE OF THE UPPER LOW AND A SHORT WAVE
TROUGH LIFTING NEWD ACROSS CENTRAL TX HAS RESULTED IN EXTENSIVE
CLOUDS AND CONVECTION OVER PARTS OF CENTRAL/ERN TX THIS MORNING WITH
CLOUDS EXTENDING DOWNSTREAM INTO THE OZARKS REGION. THIS IS LIKELY
TO LIMIT DIURNAL HEATING TO AREAS WHERE BREAKS IN CLOUDS MAY
DEVELOP. HOWEVER...CONTINUED NWD TRANSPORT OF LOW LEVEL MOISTURE
WILL CONTRIBUTE TO DESTABILIZATION WITH CAPE OF 500-1000 J/KG
POSSIBLE THIS AFTERNOON AND EVENING.
CG LIGHTNING HAS INCREASED DURING THE LAST TWO HOURS OVER ERN TX
INDICATING STORM UPDRAFTS ARE BEGINNING TO INTENSIFY IN RESPONSE TO
AFOREMENTIONED DYNAMIC FORCING FOR ASCENT. LOW- AND DEEP- LAYER
VERTICAL SHEAR HAS BEEN SUFFICIENTLY STRONG FOR ISOLATED ELEVATED
STORMS TO EXHIBIT WEAK ROTATION THIS MORNING. THE PROBABILITY OF
SURFACE-BASED STORMS IS EXPECTED TO INCREASE AS THE BOUNDARY LATER
GRADUALLY WARMS/MOISTENS INTO THIS AFTERNOON...AND AS THIS
OCCURS...THERE WILL BE AN INCREASING THREAT FOR SEVERE STORMS TO
DEVELOP.
THE PRIMARY RISK FOR SEVERE STORMS INCLUDING SUPERCELLS WILL OCCUR
WITHIN THE LOW LEVEL CONFLUENT ZONE FROM ERN TX/WRN LA INTO AR THIS
AFTERNOON AND EVENING AS ONE OR MORE CONVECTIVE BANDS BECOME BETTER
ORGANIZED. CLOCKWISE TURNING LOW LEVEL HODOGRAPHS COUPLED WITH LOW
LCL HEIGHTS SUGGEST POTENTIAL FOR A FEW TORNADOES TO DEVELOP WITH
EMBEDDED SUPERCELLS. THERE WILL ALSO BE A THREAT FOR DAMAGING WIND
GUSTS...ESPECIALLY WITH STORMS ALONG THE WRN EDGE OF THE DEEP
CONVECTION AS THE MID LEVEL DRY INTRUSION TRANSLATES NEWD. STORMS
SHOULD CONTINUE SPREADING NEWD TONIGHT BUT THE OVERALL SEVERE THREAT
IS EXPECTED TO DIMINISH AFTER 03-06Z AS THE UPPER LOW LIFTS RAPIDLY
NEWD AWAY FROM THE MORE FAVORABLE MOISTURE/INSTABILITY.
..WEISS/ROGERS.. 03/11/2012
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