DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 030549
SWODY1
SPC AC 030546

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1146 PM CST FRI JAN 02 2009

VALID 031200Z - 041200Z

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

...SE TX INTO THE LOWER MS VALLEY AREA...

SHORTWAVE TROUGH OVER THE MEXICO-TX BORDER WILL DEAMPLIFY AS IT
CONTINUES EAST INTO THE MEAN RIDGE POSITION. SRN BRANCH OF THE LOW
LEVEL JET INITIALLY OVER ERN TX EARLY SATURDAY WILL SHIFT EAST INTO
THE LOWER MS VALLEY DURING THE DAY. MID TO UPPER 60S DEWPOINTS HAVE
ALREADY SPREAD INTO THE SE TX COASTAL PLAIN AND SRN LA. THIS
MOISTURE WILL LIKELY ADVECT FURTHER NWD THROUGH LA AND SRN MS ALONG
THE SSWLY LOW LEVEL JET. WSWLY FLOW ATTENDING THE UPPER TROUGH WILL
LIKELY CONTRIBUTE TO STEEPER MID-LEVEL LAPSE RATES SPREADING EWD
THROUGH SE TX AND THE LOWER MS VALLEY ABOVE THE NWD EXPANDING MOIST
AXIS. THIS PROCESS WILL RESULT IN DESTABILIZATION THAT WILL BE
TEMPERED BY THE LIKELIHOOD OF WIDESPREAD CLOUDS AND EARLY CONVECTIVE
DEVELOPMENT WITHIN ZONE OF LIFT ACCOMPANYING THE UPPER TROUGH.

LATEST MODEL GUIDANCE DEVELOPS STORMS BY 12Z ALONG DEVELOPING WARM
CONVEYOR BELT NEAR THE CNTRL AND SE TX COAST. THIS ACTIVITY SHOULD
EXPAND NE INTO LA BY LATE MORNING...CONTINUING ENE DURING THE DAY.
GIVEN LIMITED POTENTIAL FOR DIABATIC HEATING DUE TO THE EARLY ONSET
OF DEVELOPMENT...STORMS COULD BE SLIGHTLY ELEVATED...BUT BASED CLOSE
ENOUGH TO THE SURFACE TO POSE A RISK OF DAMAGING WIND. LOW LEVEL
HODOGRAPHS ALONG THE LOW LEVEL JET AXIS MAY BECOME SUFFICIENT FOR A
THREAT OF LOW LEVEL MESOCYCLONES AND POSSIBLY AN ISOLATED TORNADO OR
TWO.

POTENTIAL WILL ALSO EXIST FOR ADDITIONAL STORMS TO DEVELOP UPSTREAM
OF THIS ACTIVITY FROM ERN TX...FARTHER NORTH INTO LA WITHIN ZONE OF
DPVA AND LIFT EAST OF VORT MAX. INITIAL THREAT WITH THIS ACTIVITY
WILL PROBABLY BE LARGE HAIL. HOWEVER...IF SUFFICIENT HEATING
DEVELOPS...STORMS MAY EVENTUALLY BECOME SURFACE BASED AND POSE A
RISK FOR DAMAGING WIND AS WELL AS AN ISOLATED TORNADO. THREAT IN ERN
TX IS MORE CONDITIONAL GIVEN LIKELIHOOD OF A STRONGER CAP AND
TENDENCY FOR THE STRONGER FORCING TO SHIFT EAST OF THIS REGION
BEFORE SURFACE HEATING DEVELOPS. THE THREAT WILL GRADUALLY DECREASE
OVERNIGHT AS ZONE OF FORCING ATTENDING THE SHORTWAVE TROUGH MOVES NE
OF INSTABILITY AXIS.

..DIAL.. 01/03/2009

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