Friday, February 15, 2008

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 150605
SWODY2
SPC AC 150604

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1204 AM CST FRI FEB 15 2008

VALID 161200Z - 171200Z

..THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF SOUTHEAST THROUGH
EAST CNTRL TX...

..THERE IS A SLGT RISK OF SVR TSTMS FROM TX INTO THE LOWER MS
VALLEY...

..SYNOPSIS...

SPLIT FLOW PATTERN WILL PERSIST THROUGH SATURDAY. MODEL CONSENSUS IS
THAT UPPER LOW CURRENTLY OVER THE SWRN U.S. WILL ADVANCE EWD THROUGH
TX SATURDAY AND INTO THE LOWER MS VALLEY SATURDAY NIGHT. SRN PORTION
OF COLD FRONT CURRENTLY EXTENDING FROM THE GREAT LAKES SWWD THROUGH
WRN TX WILL LIKELY STALL ACROSS S TX. THIS BOUNDARY WILL THEN BEGIN
TO LIFT NWD AS A WARM FRONT AS A STRONG SLY LOW LEVEL JET DEVELOPS
ACROSS TX.

..TX THROUGH THE LOWER MS VALLEY AREA...

OBSERVATIONS SHOW THE BOUNDARY LAYER CONTINUES TO MODIFY ACROSS THE
WRN GULF WITH UPPER 60S DEWPOINTS INDICATED OFF THE SERN TX COAST.
THE 00Z CORPUS CHRISTI AND BROWNSVILLE SOUNDINGS SHOW A DEEP AND
MOIST BOUNDARY LAYER OVERSPREAD BY A SUBSTANTIAL ELEVATED MIXED
LAYER. GIVEN THE FRONT IS NOT EXPECTED TO ADVANCE INTO THE
GULF...PARTIALLY MODIFIED GULF AIR WITH MID TO UPPER 60S DEWPOINTS
WILL LIKELY ADVANCE THROUGH THE WARM SECTOR ACROSS SOUTH AND CNTRL
TX AS THE WARM FRONT LIFTS NWD. ELEVATED STORMS WILL BE ONGOING
WITHIN ZONE OF STRONG WARM ADVECTION AND LIFT NORTH OF THE WARM
FRONT FROM PARTS OF CNTRL AND NWRN TX THROUGH E CNTRL AND NE TX.
THIS PRECIPITATION WILL LIKELY REINFORCE THE COOL AIR AND MAY SLOW
THE NWD PROGRESSION OF THE WARM FRONT. PRESENCE OF STEEP MID LEVEL
LAPSE RATES ASSOCIATED WITH THE EML ABOVE THE MOIST BOUNDARY LAYER
WILL LIKELY CONTRIBUTE TO MODERATE INSTABILITY IN WARM SECTOR OVER
SOUTH THROUGH E CNTRL TX.

PRIMARY UNCERTAINTY AT THIS TIME IS WHETHER OR NOT STORMS WILL BE
ABLE TO INITIATE WARM SECTOR AWAY FROM EWD ADVANCING COLD FRONT
GIVEN POTENTIAL FOR A CAP ASSOCIATED WITH THE EML. THE CAP SHOULD
GRADUALLY WEAKEN DURING THE DAY AS THE BOUNDARY LAYER WARMS AND AS
LARGE SCALE ASCENT AND HEIGHT FALLS INCREASE DOWNSTREAM FROM EWD
ADVANCING SHORTWAVE TROUGH. VERY LARGE LOW LEVEL HODOGRAPHS AND DEEP
SHEAR ASSOCIATED WITH THE UPPER TROUGH AND ITS ATTENDANT LOW LEVEL
JET WILL SUPPORT ORGANIZED STORMS INCLUDING SUPERCELLS. TORNADO
POTENTIAL WILL BE HIGHEST IF THE CAP WEAKENS ENOUGH FOR A FEW
DISCRETE STORMS TO DEVELOP WITHIN THE WARM SECTOR AHEAD OF THE
FRONT. OTHERWISE PRIMARY CONVECTIVE MODE WILL LIKELY EVOLVE TO
LINEAR...BUT WITH EMBEDDED LEWP AND SUPERCELLS STRUCTURES. DAMAGING
WIND...A FEW TORNADOES AND LARGE HAIL WILL BE POSSIBLE AS THIS
ACTIVITY ADVANCES EWD WITH LARGEST CONCENTRATION OF SEVERE WEATHER
EXPECTED IN MODERATE RISK AREA. SEVERE THREAT WILL CONTINUE BUT
GRADUALLY DECREASE AS THE LINE ADVANCES INTO THE MS VALLEY WHERE
INSTABILITY WILL BE MORE LIMITED.

.DIAL.. 02/15/2008

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