MESO: Mesoscale Discussion 0304

ACUS11 KWNS 231910
SWOMCD
SPC MCD 231909
LAZ000-MSZ000-TXZ000-232045-

MESOSCALE DISCUSSION 0304
NWS STORM PREDICTION CENTER NORMAN OK
0209 PM CDT SAT MAR 23 2013

AREAS AFFECTED...TX...LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 231909Z - 232045Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A PORTION OF ERN TX AND MUCH OF NRN LA CONTINUE TO BE
MONITORED FOR AN INCREASING CHANCE FOR TSTM DEVELOPMENT INTO THE
AFTERNOON HOURS. A WATCH REMAINS POSSIBLE ACROSS THESE AREAS.

DISCUSSION...RECENT INCREASE IN TSTMS ACROSS WOOD...SMITH...AND
HENDERSON COUNTIES IN E TX MAY BE THE FIRST SIGNS THAT STRONGER
LARGE SCALE FORCING IS BEGINNING TO SPREAD EAST ACROSS THE REGION IN
RESPONSE TO THE DIGGING VIGOROUS UPPER TROUGH ACROSS CO/NM. WHILE
MUCH OF THE AREA FROM E TX INTO NRN LA WAS WELL NORTH OF
SURFACE-BASED INSTABILITY AND A WARM/QUASI-STATIONARY FRONT ALONG
THE UPPER TX COAST...INDICATIONS ARE THAT STEEP LAPSE RATES ABOVE
THE STABLE SURFACE LAYER AND MOISTENING THROUGH THE LOWER LEVELS
WILL CONTINUE TO CONTRIBUTE TO STRONG INSTABILITY. AS LIFT
STRENGTHENS WITH THE APPROACH OF THE UPPER SYSTEM THROUGH THIS
EVENING...EXPECT BOTH STORM COVERAGE AND INTENSITY TO INCREASE.
DYNAMIC FORCING FOR ASCENT SHOULD BECOME INCREASINGLY FOCUSED ALONG
AND NORTH OF WEAK FRONTAL WAVE CYCLONE TRACK. THIS LOW MAY BE TAKING
SHAPE OVER E TX ATTM AND IS FORECAST TO DEVELOP ENEWD ACROSS CNTRL
LA THROUGH THIS EVENING. CONTINUED DESTABILIZATION AND POTENT BULK
SHEAR ON THE ORDER 50-60KT SHOULD PROMOTE STOUT AND PERSISTENT TSTM
UPDRAFTS CAPABLE OF PRODUCING LARGE HAIL. WIND DMG AND SOME TORNADO
POTENTIAL MAY INCREASE LATER AS LOW CENTER CONSOLIDATES OVER LA
WHERE MODEST WARMING OF RECOVERING MARITIME TROPICAL AIRMASS COULD
CONTRIBUTE TO SURFACE-BASED STORM INITIATION.

..CARBIN/HART.. 03/23/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...JAN...LCH...SHV...

LAT...LON 32789483 32159508 31539479 31029428 31039321 31119265
31419160 32019127 32659125 32879179 33039439 32789483

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