SWODY1
SPC AC 150556
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1156 PM CST THU FEB 14 2008
VALID 151200Z - 161200Z
..THERE IS A SLGT RISK OF SVR TSTMS PORTIONS
W-CENTRAL...SW...CENTRAL AND S-CENTRAL TX...
..SYNOPSIS...
IN MID/UPPER LEVELS...POSITIVELY TILTED SYNOPTIC TROUGH IS EVIDENT
ATTM FROM NERN CANADA SWWD ACROSS NRN PLAINS AND CENTRAL
ROCKIES...TO LOWER CO RIVER VALLEY REGION...THEN OFFSHORE BAJA.
ANCHORING CYCLONE -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER
SRN PORTIONS CA/NV...IS EXPECTED TO PIVOT EWD DURING THIS
PERIOD...REACHING VICINITY SWRN CORNER OF NM OR ELP AREA BY 16/12Z.
AT SFC...COLD FRONT INITIALLY ANALYZED OVER MO/OK/W TX IS EXPECTED
TO MOVE SEWD ACROSS REMAINDER OK AND MOST OF NRN/WRN/CENTRAL TX. BY
16/00Z...FRONT SHOULD BECOME QUASISTATIONARY OVER RIO GRANDE VALLEY
INVOF DRT...AND INTO NEARBY MEX HIGHLANDS. FRONT SHOULD
DECELERATE/STALL LATER IN PERIOD ACROSS S-CENTRAL/SE TX...IN
RESPONSE TO CONTINUING SFC LEESIDE CYCLOGENESIS OVER RIO GRANDE
VALLEY AND ADJACENT PORTIONS NERN MEX. BY 16/12Z...PRIND SFC MAP
WILL FEATURE LOW INVOF DRT...WITH QUASISTATIONARY/MARINE FRONT EWD
ACROSS S-CENTRAL/SE TX THEN SEWD ACROSS N-CENTRAL GULF.
..CENTRAL/S TX...NEAR FRONT...
ELEVATED MIXED LAYER AIR MASS -- ILLUSTRATED WELL BY OBSERVED 15/00Z
RAOBS FROM BRO/CRP/DRT -- SHOULD PERSIST FOR ONE MORE DAY AMIDST
SWLY MIDLEVEL WINDS OVER THIS REGION AND HEATING OF THAT PORTION OF
MEX PLATEAU AHEAD OF UPPER LOW. AS SUCH...SBCINH WILL REMAIN STRONG
THROUGHOUT DAY INVOF AND S OF FRONT...DESPITE DIABATIC SFC HEATING
AND INCREASING LOW LEVEL MOISTURE. LITTLE...IF ANY...SFC-BASED
THUNDER IS LIKELY BEFORE DARK...WITH ONE POSSIBLE EXCEPTION. WITH
FRONTAL SEGMENT PERHAPS STALLING INVOF SERRANIAS DEL BURRO
RANGE...CONVERGENT UPSLOPE WINDS IN BOUNDARY LAYER WILL ADVECT
INCREASING MOISTURE INTO THOSE MOUNTAINS. CONSIDERABLE UNCERTAINTY
REMAINS AS TO WHETHER MOISTURE AND LIFT WILL BE SUFFICIENT FOR THIS
BEFORE DARK...BUT LATE AFTERNOON OR EVENING CONVECTION MAY DEVELOP
OVER HIGHER TERRAIN AND MOVE EWD OR ENEWD ALONG FRONT INTO TX. ANY
SUCH TSTMS MAY PRODUCE LARGE HAIL AND DAMAGING GUSTS.
EXPECT INCREASING MOISTURE AND LOWERING LCL DURING EVENING INVOF RIO
GRANDE...WITH SEVERAL HOURS WHERE EFFECTIVE LIFTED PARCELS MAY
REMAIN SFC-BASED. THEREFORE...CANNOT RULE OUT TORNADO/WIND
POTENTIAL AS WELL AS HAIL...AFTER DARK...NEAR FRONTAL ZONE. ALONG
FRONT...EXPECT BACKED SFC WINDS TO CONTRIBUTE TO EFFECTIVE SHEAR
PROFILES 50-60 KT...30-40 KT STORM-RELATIVE INFLOW NEAR SFC...AND
0-3 KM SRH UP TO 400 J/KG...FOR ANY CONVECTION THAT CAN BREAK CAP
AND REMAIN ROOTED AT SFC.
..W TX...NW OF FRONT...
GEN TSTM POTENTIAL IS FCST TO SHIFT EWD FROM AZ/NM INTO THIS
REGION...PRIMARILY AFTER DARK. THIS WILL OCCUR AS LEADING EDGE OF
MIDLEVEL DPVA -- OCCURRING AHEAD OF PROGRESSIVE LOW ALOFT -- BEGINS
TO IMPINGE UPON WRN FRINGES OF ELEVATED/LOW-LEVEL WAA FIELD AND
MOISTURE TRANSPORT. TSTM COVERAGE AND INTENSITY EACH SHOULD
INCREASE WITH TIME OVERNIGHT...ACROSS W TX...AS MUCINH DIMINISHES
AND INCREASINGLY MOIST AIR MASS ABOVE FRONTAL LAYER IS FORCED
ISENTROPICALLY TO LFC. MEANWHILE...INCREASE IN THETAE WITHIN THIS
REGIME...AND ACCOMPANYING 35-50 KT SELY LLJ - WILL BOOST ELEVATED
MUCAPES ABOVE 1000 J/KG WITHIN 100-150 NM NW OF FRONT...AND INTO
500-1000 J/KG RANGE OVERNIGHT ACROSS PORTIONS OF PERMIAN BASIN AND
LOW ROLLING PLAINS REGION. WHEN JUXTAPOSED WITH STRENGTHENING
GRADIENT WINDS ALOFT AND INCREASING DEEP-LAYER SHEAR...CONDITIONS
WILL BECOME MORE FAVORABLE FOR ELEVATED SUPERCELLS...AND ATTENDANT
RISK OF LARGE HAIL.
.EDWARDS.. 02/15/2008
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