SWODY1
SPC AC 281959
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0159 PM CST FRI NOV 28 2008
VALID 282000Z - 291200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS CNTRL LA AND SW MS...
...SE TX/LA/SRN MS...
AN UPPER-LEVEL TROUGH IS EVIDENT OVER THE CNTRL PLAINS AND SRN
ROCKIES WITH ZONAL FLOW IN PLACE ACROSS THE GULF COAST STATES. A DRY
SLOT IS LOCATED ACROSS SE TX AND SW LA. THUNDERSTORMS ARE DEVELOPING
JUST AHEAD OF THE DRY SLOT IN LA AND ON THE NORTH SIDE ACROSS PARTS
OF EAST TX. AT THE SFC...A COLD FRONT IS LOCATED IN ECNTRL TX WITH A
QUASI-STATIONARY FRONT EXTENDING EWD ACROSS NRN LA INTO CNTRL MS.
THE THUNDERSTORM COVERAGE SHOULD BE MAINTAINED ACROSS THE REGION
SUPPORTED BY A 30 TO 40 KT LOW-LEVEL JET LOCATED NEAR THE LA-TX
STATE-LINE. CONVECTION SHOULD PERSIST THROUGH THIS EVENING AND COULD
BECOME MORE FOCUSED AS A COLD FRONT ADVANCES EWD INTO LA DURING THE
OVERNIGHT PERIOD.
CONCERNING THE SEVERE POTENTIAL...RUC ANALYSIS SHOWS SOME
INSTABILITY ACROSS SE TX...LA AND SW MS WITH SBCAPE VALUES IN THE
1000 TO 2000 J/KG RANGE. IN ADDITION...FORECAST SOUNDINGS THIS
AFTERNOON SHOW 0-6 KM SHEAR VALUES IN THE 40 TO 50 KT RANGE. THIS
COMBINATION OF SHEAR AND INSTABILITY MAY SUPPORT MARGINALLY SEVERE
STORMS THIS AFTERNOON WITH A FEW ROTATING STORMS POSSIBLE. LOW-LEVEL
SHEAR IS MAXIMIZED NEAR THE AXIS OF THE LOW-LEVEL JET ACROSS WRN LA
AND EWD ALONG A STATIONARY FRONT INTO SCNTRL MS WHERE 0-1 KM SHEAR
VALUES ARE ESTIMATED AT ABOUT 25 KT. THIS SHOULD BE SUFFICIENT FOR
AN ISOLATED TORNADO OR TWO WITH ROTATING STORMS THAT TRACK EWD ALONG
THE BOUNDARY IN CNTRL LA AND SW MS. THE STRONGER CELLS MAY HAVE
POTENTIAL FOR STRONG WIND GUSTS ESPECIALLY ACROSS LA WHERE LOW-LEVEL
LAPSE RATES SHOULD STEEPEN SOME LATE THIS AFTERNOON.
..BROYLES.. 11/28/2008
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