DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 261242
SWODY1
SPC AC 261240

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0640 AM CST MON NOV 26 2012

VALID 261300Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM NORTHEAST TX INTO PORTIONS
OF AR/LA/MS...

...ARKLATEX REGION...
MORNING WATER VAPOR LOOPS SHOW A DEVELOPING LARGE SCALE UPPER TROUGH
OVER THE WESTERN AND CENTRAL UNITED STATES. A SOUTHERN STREAM
IMPULSE IS MOVING ACROSS THE BAJA PENINSULA AND WILL APPROACH THE
WESTERN GULF OF MEXICO BY EVENING. MEANWHILE AT THE SURFACE...A
COLD FRONT IS SAGGING SOUTHWARD ACROSS OK INTO THE ARKLATEX REGION.
CURRENT INDICATIONS ARE THAT THE APPROACHING UPPER TROUGH WILL
RESULT IN SCATTERED STRONG-SEVERE STORMS ALONG THE COLD FRONT LATER
THIS EVENING AND TONIGHT.

LOW LEVEL WINDS ARE NOT PARTICULARLY STRONG THIS MORNING...NOR WILL
THEY INCREASE SIGNIFICANTLY THROUGH THE PERIOD. HOWEVER...
INCREASING LOW LEVEL WARM ADVECTION/ASCENT AHEAD OF THE UPPER TROUGH
WILL RESULT IN GREATER COVERAGE OF SHOWERS AND THUNDERSTORMS THROUGH
THE DAY. THIS PROCESS HAS ALREADY COMMENCED ACROSS PARTS OF LA/MS.
WHILE AN ISOLATED STRONG STORM IS POSSIBLE FROM THIS MORNING/EARLY
AFTERNOON ACTIVITY...THE PRIMARY SEVERE THREAT IS EXPECTED AFTER
00Z.

MOST MODEL SOLUTIONS AGREE THAT MORE ORGANIZED THUNDERSTORM ACTIVITY
WILL DEVELOP ALONG THE APPROACHING COLD FRONT THIS EVENING FROM
NORTHEAST TX...ACROSS SOUTHERN AR...INTO NORTHERN MS. THE AIR MASS
IN THIS REGION WILL BECOME MODERATELY MOIST/UNSTABLE WITH
SUFFICIENTLY STEEP MID LEVEL LAPSE RATES TO YIELD MLCAPE VALUES OF
1500-2000 J/KG. LOW AND MID LEVEL FORECAST WIND FIELDS WILL PROMOTE
SUPERCELL STORM STRUCTURES CAPABLE OF LARGE HAIL AND DAMAGING WINDS.
VEERED LOW LEVEL WINDS ARE LIKELY TO MITIGATE THE RISK OF LOW LEVEL
MESOCYCLONES...BUT AN ISOLATED TORNADO CANNOT BE RULED OUT. THE
ACTIVITY WILL SPREAD SOUTHEASTWARD ACROSS NORTHERN LA AND
NORTHERN/CENTRAL MS BY LATE EVENING AND EVENTUALLY WEAKEN DUE TO
DECREASING INSTABILITY.

..HART/DISPIGNA.. 11/26/2012

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