[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 061238
SWODY1
SPC AC 061237

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0737 AM CDT SAT MAY 06 2006

VALID 061300Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF CENTRAL/SRN TX
INTO SRN LA...

...UPPER TX COAST ACROSS SRN LA...
LINEAR MCS WAS MOVING INTO THE SABINE RIVER VALLEY WITH MAIN IMPETUS
BOWING OFF THE SERN TX COAST AT 12Z.  THUS...SLOWER MOVING N-S
ORIENTED AXIS OF STRONG STORMS WILL SPREAD EWD ACROSS WRN LA THIS
MORNING AS WEAK SHORTWAVE TROUGH SHIFTS TOWARD THE LOWER MS RIVER
VALLEY.  COMPOSITE OUTFLOW BOUNDARY/COASTAL FRONT EXTENDED FROM THE
MS RIVER DELTA WWD INTO LINEAR MCS JUST NORTH OF THE UPPER TX COAST
EARLY THIS MORNING.  A VERY MOIST BOUNDARY LAYER REMAINS SOUTH OF
THIS FRONT WHICH WILL LIKELY LIFT SLOWLY NWD AS PRESSURE FALLS AND
SLY LOW LEVEL WINDS INCREASE ACROSS SRN LA TODAY.  MID LEVEL LAPSE
RATES REMAIN QUITE STEEP AND WILL SUPPORT A VERY UNSTABLE AIR MASS
BY THE LATE MORNING FROM PORTIONS OF CENTRAL LA EWD TO JUST OFF THE
CENTRAL GULF COAST.  MID LEVEL WINDS ASSOCIATED WITH APPROACHING
MID/UPPER LEVEL TROUGH WILL REMAIN SUFFICIENT FOR 40-50 KT DEEP
LAYER SHEAR ACROSS THIS REGION.  THEREFORE...EXPECT AN INCREASE IN
SEVERE THREAT DURING THE MID TO LATE MORNING INTO PORTIONS OF
CENTRAL LA AS HEATING COMMENCES AND COASTAL FRONT SHIFTS SLOWLY NWD.
 THOUGH OVERALL MODE MAY REMAIN LINEAR AS N-S ORIENTED OUTFLOW
BOUNDARY SURGES EWD TODAY...SHEAR WILL BE SUFFICIENT FOR SUPERCELLS
ESPECIALLY IF ACTIVITY DEVELOPS AHEAD OF ONGOING CONVECTIVE LINE OR
LINE BECOMES MORE BROKEN.  MESO LOW MAY FORM ALONG INTERSECTION OF
OUTFLOW BOUNDARY AND E-W ORIENTED COASTAL FRONT SUPPORTING A THREAT
OF TORNADOES GIVEN AMOUNT OF SHEAR.  EASTERN AND NORTHERN EXTENT OF
SUBSEQUENT SEVERE THREAT WILL BE MODULATED BY MORE LIMITED
INSTABILITY ACROSS NRN LA AND EAST OF THE MS RIVER.

...SWRN TX TO THE MIDDLE TX COAST/DEEP SOUTH TX...
OUTFLOW BOUNDARY WILL LIKELY SLOW ITS SWD MOTION FROM THE MIDDLE TX
COAST TOWARDS THE BIG BEND REGION AND LIKELY LIFT SLOWLY NWD OR
ERODE THIS AFTERNOON.  AIR MASS REMAINS QUITE MOIST AND
CONDITIONALLY VERY UNSTABLE FROM DEEP SOUTH TX INTO RIO GRANDE
VALLEY SOUTH OF THIS OUTFLOW WITH SFC DEW POINTS IN THE LOWER 70S
BELOW 8+ C/KM MID LEVEL LAPSE RATES.  IN ADDITION...MODEST WNWLY
FLOW ALOFT WILL SUPPORT 45-55 KT EFFECTIVE SHEAR THROUGH THE PERIOD.
 GIVEN STEEPNESS OF MID LEVEL LAPSE RATES AND AMOUNT OF
MUCAPE...ELEVATED SEVERE THUNDERSTORMS INCLUDING SUPERCELLS MAY
PERSIST THIS MORNING WITH A THREAT OF LARGE HAIL FROM THE TX HILL
COUNTRY INTO THE COASTAL PLAIN.  MORE VIGOROUS DEVELOPMENT IN THE
FORM OF SUPERCELLS IS EXPECTED TO BE DRIVEN BY STRONG HEATING AND
CONVERGENCE ALONG SURFACE OUTFLOW BOUNDARIES/COLD FRONT AND LEE
TROUGH/DRY LINE FROM THE EDWARDS PLATEAU/BIG BEND REGION INTO THE
LOWER RIO GRANDE VALLEY BY 20Z.  GIVEN EXPECTED SHEAR...EXTREME
INSTABILITY WILL SUPPORT A FEW INTENSE SUPERCELLS AGAIN LATE TODAY
AND THIS EVENING SPREADING ESEWD.  AS HAS BEEN THE CASE THE PAST FEW
DAYS...VERY LARGE HAIL AND POSSIBLY A FEW TORNADOES WILL BE PRIMARY
SEVERE THREATS.  HOWEVER...AN INCREASED WIND THREAT MAY PERSIST
THROUGH THE EVENING/OVERNIGHT AS ONE OR MORE MCSS EVOLVE.

..EVANS.. 05/06/2006