DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 191945
SWODY1
SPC AC 191943

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0243 PM CDT TUE MAR 19 2013

VALID 192000Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR CNTRL TX...

...CNTRL TX...
AFTERNOON WV IMAGERY SHOWS A SHORTWAVE IMPULSE MOVING EWD ACROSS
AZ...AND SHORT-TERM MODEL GUIDANCE INDICATES THAT THIS FEATURE WILL
ENTER TX TONIGHT. AT THE SURFACE...ZONE OF CONVERGENCE/FRONTAL
BOUNDARY EXISTS BETWEEN ELY WINDS OVER NRN TX AND SLY FLOW OVER
SRN/CNTRL TX. DEWPOINTS ALONG AND S OF THE BOUNDARY ARE IN THE 50S
TO LOW 60S...WHICH ARE ALSO JUXTAPOSED WITH TEMPERATURES WARMING
INTO THE 80S. AS A RESULT...THE AIRMASS WITHIN THE SLIGHT RISK AREA
OVER CNTRL TX IS QUICKLY DESTABILIZING...WITH MUCAPE VALUES FORECAST
TO RANGE THIS EVENING FROM 500 J/KG ALONG AND IMMEDIATELY N OF THE
BOUNDARY TO AROUND 2000 J/KG S OF THE BOUNDARY.

COMBINATION OF INCREASING LARGE-SCALE ASCENT AHEAD OF THE SWRN
IMPULSE AND LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY WILL AID IN
ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT THIS EVENING AND
NIGHT. STEEP MIDLEVEL LAPSE RATES AND STRONG DEEP-LAYER SHEAR VALUES
/IN EXCESS OF 50 KT IN THE 0-6 KM LAYER/ WILL FAVOR A RISK OF A FEW
SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL. IN ADDITION...STORMS MAY
GROW UPSCALE INTO A SMALL MCS DURING THE NIGHT ALONG THE FRONT AS IT
MOVES SWD TOWARD SRN TX AND THE GULF COAST...WHICH WOULD PROMOTE A
THREAT FOR ISOLATED DAMAGING WIND GUSTS.

..GARNER.. 03/19/2013

.PREV DISCUSSION... /ISSUED 1102 AM CDT TUE MAR 19 2013/

...TX...
MORNING WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH TRACKING
QUICKLY SOUTHEASTWARD ACROSS NM/CO. THIS FEATURE WILL MOVE INTO THE
SOUTHERN PLAINS THIS AFTERNOON...SPREADING LARGE SCALE FORCING FOR
ASCENT ACROSS MUCH OF TX. MODEL GUIDANCE IS IN GOOD AGREEMENT OF A
STRENGTHENING LOW LEVEL BAROCLINIC ZONE AND SURFACE CYCLOGENESIS
OVER WEST CENTRAL TX BY 00Z. SOUTHERLY/SOUTHEASTERLY LOW LEVEL
WINDS ACROSS TX WILL DRAW GULF MOISTURE NORTHWESTWARD... RESULTING
IN A ZONE OF RISK FOR STRONG/SEVERE THUNDERSTORMS LATE THIS
AFTERNOON AND TONIGHT.

THUNDERSTORMS ARE EXPECTED TO DEVELOP BY EARLY EVENING IN REGION OF
STEEP LOW LEVEL LAPSE RATES AND INCREASING CAPE...GENERALLY BETWEEN
FTW AND SJT. THESE STORMS WILL INCREASE IN COVERAGE AND INTENSITY
DURING THE EVENING AS THEY SPREAD SOUTHEASTWARD ACROSS THE SLIGHT
RISK AREA. STRONG EFFECTIVE SHEAR AND STEEP MID LEVEL LAPSE RATES
WILL PROMOTE ROTATING STORMS CAPABLE OF LARGE HAIL AND DAMAGING
WINDS. ACTIVITY SHOULD BEGIN TO WEAKEN TOWARD MIDNIGHT AS IT
SPREADS TOWARD THE UPPER TX GULF COAST.

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