SWODY1
SPC AC 101242
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0642 AM CST MON NOV 10 2008
VALID 101300Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PART OF THE SRN
PLAINS...
...SRN PLAINS...
LITTLE CHANGE ATTM WITH OVERALL SEVERE TSTM FORECAST AHEAD OF
INTENSE AUTUMN MID/UPPER LEVEL LOW NOW OVER THE FOUR CORNERS REGION.
THIS SYSTEM WILL SHIFT EWD AND THEN NEWD THROUGH TONIGHT WITH
ASSOCIATED SHORTWAVE TROUGH BECOMING NEGATIVELY TILTED DURING THE
LATTER HALF OF FORECAST PERIOD AS IT MOVES ACROSS THE SRN PLAINS.
ENHANCEMENT OF SSWLY LLJ IS ALREADY UNDERWAY OVER MUCH OF TX INTO OK
AT DAYBREAK WITH 1KM WINDS AOA 50 KT AT JTN PROFILER AT 11Z. LOW
LEVEL MOISTURE RETURN IS ALSO CONTINUING EARLY THIS MORNING WITH
RICH GULF MOISTURE /I.E. SURFACE DEW POINTS NEAR 70F/ ADVECTING OUT
OF SRN TX...SAMPLED BY BOTH BRO AND CRP SOUNDINGS AT 12Z. SURFACE
LOW SHOULD CONSOLIDATE OVER THE SRN HIGH PLAINS THROUGH THE DAY WITH
DRY LINE/SURFACE TROUGH ARCING SSEWD ACROSS WRN OK INTO CENTRAL TX
TO NEAR THE BIG BEND REGION. EFFECTIVE WARM FRONT WILL LIKELY
BECOME REINFORCED BY EARLY DAY MOIST CONVECTION FROM SERN INTO NWRN
TX.
/MUCH OF CENTRAL/EAST TX AND SOUTHERN OK/WESTERN LA/
LOW LEVEL THETA-E ADVECTION WILL CONTINUE TO SUPPORT INCREASE IN
MOIST CONVECTION AND THUNDERSTORMS ACROSS CENTRAL/ERN TX ACROSS OK
THROUGH THE MORNING. COMBINATION OF STEEP MID LEVEL LAPSE
RATES/COLD MID LEVEL TEMPERATURES AND STRONG CLOUD-LAYER SHEAR
SHOULD SUPPORT A RISK OF HAIL...SOME SEVERE...WITH THIS ELEVATED
ACTIVITY THROUGH THE DAY. HOWEVER...SEVERE THREAT SHOULD INCREASE
DURING THE AFTERNOON AS HEATING WEAKENS CAPPING ABOVE MOISTENING
BOUNDARY LAYER AIR MASS...ESPECIALLY OVER PARTS OF CENTRAL TX WHERE
COLLOCATION OF MODEST INSTABILITY AND WEAKEST CAPPING WILL OCCUR.
ADDITIONAL RISK AREA MAY EVOLVE NEARER THE TX COAST INVOF COASTAL
FRONT WHERE EVEN MODEST HEATING WILL CREATE WEAK CAPPING FOR
SURFACE-BASED PARCELS BY THE EARLY AFTERNOON. SHEAR WILL REMAIN
EXTREME /EFFECTIVE SHEAR FROM 50-70 KT...SFC-1 KM SRH IN EXCESS OF
200 M2 S-2/ AND ENHANCE ANY SURFACE-BASED SEVERE THREAT ALONG WITH
ATTENDANT THREAT OF TORNADOES WITH ANY DISCRETE SUPERCELLS.
CONDITIONAL RISK OF ONE OR TWO SIGNIFICANT TORNADOES ALSO APPEARS
WARRANTED OVER THIS AREA. THREAT WILL LIKELY PERSIST OVERNIGHT INTO
TUESDAY MORNING OVER CENTRAL TX INVOF SURFACE COLD FRONT AND INTO
ERN TX/FAR WRN LA WITH LEADING ACTIVITY.
/TX PANHANDLE AND WESTERN/NORTHERN OK INTO SOUTHERN KS/
MOISTURE RETURN/SURFACE DESTABILIZATION WILL ESPECIALLY BE LIMITED
WITH NWWD EXTENT IN CLOSER PROXIMITY TO THE UPPER LOW AND SURFACE
LOW/TRIPLE POINT ACROSS THE TX PANHANDLE/WESTERN OK. ASIDE FROM
MORNING HAIL POTENTIAL...PROVIDED SUFFICIENT INSOLATION/MODEST
HEATING OCCURS THIS AFTERNOON...A FEW SEVERE TSTMS CAPABLE OF
HAIL/STRONG WINDS WILL BE POSSIBLE THIS AFTERNOON/EARLY EVENING. AN
ISOLATED TORNADO CANNOT BE RULED OUT IN VICINITY OF THE TRIPLE
POINT/SURFACE OCCLUSION ACROSS THE EASTERN/NORTHERN TX PANHANDLE AND
WESTERN OK. HOWEVER...OVERALL SCENARIO DOES NOT APPEAR TO WARRANT A
CATEGORICAL SLIGHT RISK GIVEN THE LIMITED MOISTURE/BUOYANCY.
..EVANS.. 11/10/2008
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