DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 270100
SWODY1
SPC AC 270057

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0757 PM CDT FRI APR 26 2013

VALID 270100Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS MAIN BODY OF OK EXCEPT NRN
PORTIONS...EXTREME WRN AR...RED RIVER REGION NEAR PRX...

...SYNOPSIS...
SPLIT-FLOW PATTERN ALOFT CONTINUES AROUND REGIME OF CENTRAL CONUS
TROUGHING. MAIN FEATURE WILL CONTINUE TO BE SHORTWAVE TROUGH -- NOW
EVIDENT IN RAOB DATA...PROFILER...VWP AND MOISTURE CHANNEL IMAGERY
WRN IA/SERN NEB SWWD ACROSS CENTRAL KS TO ERN NM. PERTURBATION IS
FCST TO MOVE EWD THROUGH REMAINDER PERIOD...REACHING NRN MO...SERN
KS...WRN OK AND TX SOUTH-PLAINS REGION BY 12Z.

AT SFC...23Z ANALYSIS DEPICTED LOW OVER FAR WRN OK NEAR TAIL END OF
CONVECTIVE BAND...WITH COLD FRONT SWWD ACROSS SERN PANHANDLE OF TX
AND THAT PORTION OF ERN NM W LBB. DRYLINE INTERSECTED COLD FRONT
NEAR WHERE I-40 CROSSES TX/OK BORDER...AND EXTENDED SEWD ACROSS SWRN
OK BEFORE ARCHING SSWWD OVER ABI AREA. DRYLINE SHOULD REMAIN CAPPED
FOR CONVECTION AND WILL BE OVERTAKEN BY COLD FRONT FROM N-S WITH
TIME. WARM FRONT EXTENDED FROM LOW SEWD ACROSS DFW METROPLEX THEN
GENERALLY EWD TO SHV AREA...AND WAS BECOMING MORE ILL-DEFINED WITH
TIME. THIS BOUNDARY IS FCST TO MOVE NWD DIFFUSELY AND MERGE WITH
STG FRONT THAT EXTENDED NEAR JWG-OKC-ADH-TXK LINE. CENTRAL OK
PORTION OF LATTER BOUNDARY WAS DRIFTING SWWD...ITS BAROCLINICITY
HAVING BEEN REINFORCED BY EARLIER PRECIP/CLOUD COVER TO ITS NE.
SERN OK/WRN AR PORTION MAY MOVE NWD AFTER ABOUT 06Z...JUST PRIOR TO
ARRIVAL OF MCS.

...MAIN BODY OF OK...AND VICINITY...
BKN BAND OF SVR TSTMS WITH HISTORY OF DAMAGING GUSTS AND ISOLATED
SVR HAIL WILL MOVE ESEWD ACROSS PORTIONS WRN/CENTRAL OK WITH
CONTINUED PRIMARY RISKS OF WIND AND HAIL. REF SPC WW 139 AND
ACCOMPANYING MESOSCALE DISCUSSIONS FOR MORE DETAILED NEAR-TERM
GUIDANCE.

CHANNEL OF MOST FAVORABLE SVR POTENTIAL APPEARS FAIRLY WELL-DEFINED
ATTM FROM EXISTING MCS SEWD ACROSS PORTIONS CENTRAL/SRN OK...MOSTLY
ALONG AND S OF CENTRAL OK FRONT. STG CAPPING EVIDENT IN 00Z FWD
RAOB SHOULD PERSIST...AND WILL LIMIT SRN EXTENT OF SVR/CONVECTIVE
THREAT. MEANWHILE...SFC-BASED POTENTIAL WILL BE LIMITED ON NRN END
BY CENTRAL/SERN OK BOUNDARY. PRIMARY CONCERN MORE THAN ABOUT 50 NM
N OF THAT FRONT...WILL BE HAIL...WHERE DEPTH/MAGNITUDE OF STATICALLY
STABLE LAYER SHOULD BECOME INCREASINGLY UNFAVORABLE FOR ALLOWING SVR
GUSTS TO PENETRATE TO SFC. DISCRETE DEVELOPMENT AHEAD OF MAIN BAND
APPEARS IMPROBABLE BECAUSE OF STG CAPPING EVIDENT OVER REGION...AND
RESULTING NECESSITY OF FORCED ASCENT FROM COMBINATION OF POSTFRONTAL
AIR AND CONVECTIVE COLD POOL.

OVERALL SVR POTENTIAL SHOULD DIMINISH AFTER ABOUT 09Z OVER SERN
OK/WRN AR REGION...AS
1. BOUNDARY LAYER ALONG AND S OF FRONT DIABATICALLY STABILIZES TO
MORE UNFAVORABLE EXTENT AND
2. FOREGOING LLJ VEERS AND BEGINS TO WEAKEN.

..EDWARDS.. 04/27/2013

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