DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 240555
SWODY1
SPC AC 240553

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1153 PM CST MON JAN 23 2012

VALID 241200Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF WCNTRL TX...THE
TX HILL COUNTRY AND MIDDLE TX COAST...

...WCNTRL TX/HILL COUNTRY/MIDDLE TX COAST...
AN UPPER-LEVEL TROUGH EXTENDING SWD FROM THE FOUR CORNERS INTO NRN
MEXICO...WILL CLOSE-OFF AND MOVE INTO FAR WEST TX TODAY. AHEAD OF
THE UPPER-LEVEL LOW...A 35 TO 45 KT LOW-LEVEL JET ACROSS CNTRL TX
WILL RESULT IN MOISTURE ADVECTION ACROSS MUCH OF THE SRN HALF OF TX.
BY LATE AFTERNOON...A MOIST AXIS WILL BE IN PLACE FROM WCNTRL TX
WHERE SFC DEWPOINTS SHOULD BE AROUND 50 F TO AROUND 65 F ALONG THE
TX COAST. SCATTERED THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE THIS
AFTERNOON ACROSS MUCH OF THE WARM SECTOR DUE TO SFC HEATING AND LIFT
ASSOCIATED WITH THE LOW-LEVEL JET. BY LATE AFTERNOON...MODEL
FORECASTS SHOW POCKETS OF MODERATE INSTABILITY IN PLACE FROM EAST OF
MIDLAND SEWD TO SOUTH OF SAN ANTONIO ALONG WITH 50 TO 60 KT 0-6 KM
SHEAR. THIS ENVIRONMENT SHOULD SUPPORT A THREAT FOR WIND DAMAGE AND
HAIL WITH THE STORMS THAT DEVELOP CLOSER TO THE INSTABILITY AXIS. A
SUPERCELL THREAT MAY ALSO DEVELOP WEST OF THE LOW-LEVEL JET FROM
AROUND DEL RIO NORTH TO NEAR SAN ANGELO WHERE MID-LEVEL LAPSE RATES
WILL BE STEEPER AND THE COMBINATION OF INSTABILITY AND DEEP LAYER
SHEAR IS FORECAST TO BE MAXIMIZED. A COUPLE TORNADOES AND ISOLATED
LARGE HAIL COULD OCCUR WITH STORMS THAT REMAIN DISCRETE AND BECOME
INTENSE LATE THIS AFTERNOON INTO EARLY EVENING.

AS THE UPPER-LEVEL LOW APPROACHES WEST TX DURING THE
EVENING...CONVECTIVE COVERAGE SHOULD MARKEDLY INCREASE ALONG THE
LEADING EDGE OF LARGE-SCALE ASCENT WITH A LINE OF THUNDERSTORMS
ORGANIZING FROM NCNTRL TX SSWWD INTO SW TX. THIS TRANSITION TO A
LINEAR MCS SHOULD KEEP A WIND DAMAGE THREAT GOING THROUGH MUCH OF
THE NIGHT. MODEL FORECASTS TIME THE LINE SEWD ACROSS THE TX HILL
COUNTRY AROUND MIDNIGHT AND ONTO THE TX COASTAL PLAIN LATE IN THE
PERIOD. SHEAR PROFILES ARE FORECAST TO BE SOMEWHAT WEAKER ACROSS THE
TX COASTAL PLAIN IN THE 06Z TO 12Z TIMEFRAME SUGGESTING THE SEVERE
THREAT MAY BECOME MARGINAL LATE IN THE PERIOD.

..BROYLES/GARNER.. 01/24/2012

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