SPC AC 111241
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0741 AM CDT SUN MAR 11 2007
VALID 111300Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS TODAY INTO TONIGHT ACROSS SW
AND CENTRAL TX...
...CENTRAL AND SW TX AREA THROUGH TONIGHT...
WATER VAPOR IMAGERY SUGGESTS THAT THE MID LEVEL TROUGH OVER NM IS
GRADUALLY EVOLVING INTO A CLOSED MID LEVEL LOW THAT WILL DRIFT SEWD
OVER SRN NM AND W TX THROUGH EARLY MONDAY. AN INITIAL EMBEDDED
SPEED MAX IS ROTATING AROUND THE SRN PERIPHERY OF THE TROUGH AS OF
12Z. THIS SPEED MAX WILL LIKELY CONTRIBUTE TO INCREASING
THUNDERSTORM COVERAGE DURING THE MORNING ACROSS W CENTRAL TX. MUCH
OF THIS CONVECTION SHOULD BE FOCUSED INVOF AN E-W ORIENTED OUTFLOW
BOUNDARY WHICH IS MOVING SLOWLY SWD...WITH A GRADUAL TREND FOR
LOW-LEVEL MOISTENING/DESTABILIZATION FROM S TO N INTO THE BOUNDARY.
AS CONVECTION INCREASES AND REINFORCES THE OUTFLOW...THE COLD POOL
SHOULD BEGIN TO MOVE A LITTLE FASTER TO THE S DURING THE AFTERNOON.
THE NERN EXTENT OF THE OUTFLOW BOUNDARY EXTENDS INTO CENTRAL AND S
CENTRAL OK IN ASSOCIATION WITH AN MCV GENERATED BY OVERNIGHT
CONVECTION. THE MCV IN CENTRAL OK WILL LIKELY BEGIN TO WEAKEN AND
MOVE TO THE NE BY MIDDAY...THUS THE OUTFLOW BOUNDARY SHOULD SLOW ITS
EWD/SEWD MOTION ACROSS SRN OK AND N/NW TX.
MID LEVEL FLOW IS EXPECTED TO BACK FROM SWLY TO SLY BY LATE TODAY
OVER NW TX AS THE CLOSED LOW DRIFTS SEWD OVER NM. MORE SWLY MID
LEVEL FLOW WILL BE MAINTAINED OVER THE RIO GRANDE INVOF DRT. STORMS
FORMING ALONG THE MORE E-W SECTION OF THE OUTFLOW BOUNDARY ACROSS W
TX WILL TEND TO BE UNDERCUT BY COOL OUTFLOW...WHILE STORMS ON THE
MORE N-S SECTION OF THE BOUNDARY IN N/NW TX MAY BE ABLE TO MOVE WITH
THE BOUNDARY IN ITS SLOW EWD PROGRESS. THERE WILL BE MARGINAL
SUPERCELL POTENTIAL WITH CONVECTION ALONG THE SURFACE BOUNDARY INTO
N/NW TX...WHILE THE MORE PROBABLE AREA FOR SUPERCELLS THIS AFTERNOON
WILL BE CLOSE TO THE RIO GRANDE AND S OF THE OUTFLOW BOUNDARY/FRONT
WHERE THE STRONGEST EFFECTIVE BULK SHEAR AND INSTABILITY COINCIDE.
BY LATE EVENING/EARLY TONIGHT... WIDESPREAD CONVECTION WILL LIKELY
REINFORCE THE COLD POOL AND RESULT IN SOME ACCELERATION OF THE
CONVECTION TOWARD THE SE ACROSS CENTRAL/S CENTRAL TX. THE PRIMARY
SEVERE THREATS SHOULD BE WIDELY SCATTERED TO SCATTERED LARGE HAIL
AND DAMAGING WIND EVENTS THROUGH LATE AFTERNOON...ALONG WITH THE
POTENTIAL FOR A TORNADO OR TWO...AND THE SEVERE STORM THREAT SHOULD
DIMINISH GRADUALLY BY TONIGHT.
..THOMPSON/GRAMS.. 03/11/2007
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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