DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 241733
SWODY2
SPC AC 241731

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1131 AM CST SUN FEB 24 2013

VALID 251200Z - 261200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...LOWER MS VALLEY...CNTRL GULF COAST AND ERN GULF COAST...

...LOWER MS VALLEY/GULF COAST STATES...
AN UPPER-LEVEL LOW WILL MOVE ACROSS THE SRN PLAINS ON MONDAY AS A
WELL-DEFINED MID-LEVEL JET TRANSLATES EWD THROUGH THE BASE OF THE
UPPER-LEVEL SYSTEM. AT THE SFC...A LOW WILL GRADUALLY DEEPEN AND
MOVE EWD ALONG THE RED RIVER AT THE TX-OK STATE-LINE. AT
DAYBREAK...A COLD FRONT SHOULD BE IN PLACE EXTENDING FROM THE SFC
LOW SWD ACROSS NORTH TX INTO THE TX HILL COUNTRY ALONG WHICH
THUNDERSTORM ACTIVITY SHOULD BE ONGOING. THE GREATEST CONCENTRATION
OF STORMS SHOULD EXIST IN NORTH TX AND SRN OK ALONG A TONGUE OF
LOW-LEVEL MOISTURE AND WEST OF A LOW-LEVEL JET. THE COLD FRONT WILL
ADVANCE QUICKLY EWD ACROSS EAST TX DURING THE MORNING AND INTO THE
LOWER MS VALLEY MONDAY AFTERNOON. THIS BOUNDARY WILL FOCUS
CONVECTIVE DEVELOPMENT BUT NUMEROUS THUNDERSTORMS SHOULD ALSO
DEVELOP WELL AHEAD OF THE FRONT ACROSS A BROAD WARM SECTOR EXTENDING
FROM LA EWD ACROSS SRN MS AND SRN AL. SQUALL-LINE DEVELOPMENT WILL
BE POSSIBLE ACROSS THE LOWER MS VALLEY AND CNTRL GULF COAST STATES
LATE MONDAY AFTERNOON. THIS LINEAR CONVECTIVE SYSTEM SHOULD PERSIST
INTO THE EVENING AS A LOW-LEVEL JET MOVES NWD FROM THE NRN GULF OF
MEXICO INTO THE CNTRL GULF COAST STATES. BY 06Z ON TUESDAY...MODEL
FORECASTS SUGGEST A WELL-DEVELOPED LINEAR MCS WILL BE LOCATED FROM
THE TN VALLEY EXTENDING SWD ACROSS AL INTO THE WRN FL PANHANDLE.

FORECAST SOUNDINGS AHEAD OF THE COLD FRONT IN THE LOWER MS VALLEY
MONDAY AFTERNOON DEVELOP MODERATE INSTABILITY ACROSS MUCH OF LA AND
SRN MS IN RESPONSE TO STRONG WARM ADVECTION AND SFC HEATING. SBCAPE
VALUES COULD REACH 1500 J/KG FROM SOUTH OF JACKSON MS TO THE NEW
ORLEANS VICINITY. IN ADDITION...0-6 KM SHEAR VALUES ARE FORECAST TO
INCREASE INTO THE 50 TO 60 KT RANGE ACROSS MUCH OF THE LOWER MS
VALLEY AS THE MID-LEVEL JET APPROACHES FROM THE WEST. THIS
ENVIRONMENT ALONG WITH 20 TO 30 KT OF LOW-LEVEL SHEAR AND A MOIST
BOUNDARY LAYER /SFC DEWPOINTS IN THE UPPER 60S F/ SHOULD BE
FAVORABLE FOR SEVERE STORMS AND POSSIBLY ROTATING STORMS. THE
DOMINANT STORM MODE COULD DETERMINE THE TYPE AND MAGNITUDE OF THE
SEVERE THREAT. A PURELY LINEAR CONVECTIVE SYSTEM WOULD FAVOR WIND
DAMAGE AS THE GREATEST THREAT. AN ISOLATED TORNADO AND HAIL THREAT
WOULD BE POSSIBLE WITH ROTATING CELLS ELEMENTS EMBEDDED IN THE LINE.
IF MORE CELLS DEVELOP WELL AHEAD OF THE LINE ACROSS THE WARM SECTOR
AND REMAIN DISCRETE...THEN THE TORNADO THREAT COULD BE GREATER. AT
THIS POINT...IT APPEARS THAT THE GREATEST SEVERE THREAT WILL EXIST
ACROSS SE LA...SRN MS AND FAR SRN AL WHERE THE COMBINATION OF
INSTABILITY...SHEAR AND MOISTURE WILL BE MAXIMIZED NEAR PEAK HEATING
MONDAY AFTERNOON. WILL ADD A 30 PERCENT SEVERE PROBABILITY ACROSS
THE LOWER MS VALLEY.

..BROYLES.. 02/24/2013

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