DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 180540
SWODY1
SPC AC 180538

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1238 AM CDT FRI OCT 18 2013

VALID 181200Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE TX BIG
COUNTRY/EDWARDS PLATEAU...

...SYNOPSIS...
A LONGWAVE TROUGH WILL DOMINATE MUCH OF THE CONUS THROUGH THE
PERIOD...WITH PRIMARY FEATURE OF CONVECTIVE INTEREST BEING AN
EMBEDDED SHORTWAVE IMPULSE ROTATING THROUGH THE BASE OF THE TROUGH
FROM THE SRN ROCKIES INTO THE CNTRL/SRN PLAINS. ATTENDANT SURFACE
COLD FRONT WILL ACCELERATE SWD ACROSS THE SRN PLAINS DURING THE LATE
AFTERNOON INTO TONIGHT AS THE IMPULSE EJECTS EWD. A DRYLINE WILL MIX
EWD S OF THE FRONT IN WRN TX.

...TX...
GREATEST RISK OF SEVERE STORMS IN THE FORM OF LARGE HAIL IS
ANTICIPATED NEAR THE INTERSECTION OF THE DRYLINE/COLD FRONT OVER
PARTS OF THE BIG COUNTRY/EDWARDS PLATEAU IN THE LATE AFTERNOON/EARLY
EVENING. HERE...A RELATIVELY NARROW PLUME OF GULF MOISTURE RETURN
SHOULD YIELD UPPER 50S TO LOWER 60S SURFACE DEW POINTS. THIS WILL
OVERLAP WITH THE EDGE OF THE SRN HIGH PLAINS EML PLUME AND LIKELY
RESULT IN MLCAPE APPROACHING 1000-1500 J/KG AT PEAK HEATING.

WLY FLOW AT THE TOP OF THE PBL SHOULD EFFECTIVELY MAINTAIN CAPPING
OVER THE WARM SECTOR. HOWEVER...LOW-LEVEL CONVERGENCE ALONG THE
AFOREMENTIONED BOUNDARIES IN COMBINATION WITH DCVA AHEAD OF THE HIGH
PLAINS MID-LEVEL IMPULSE SHOULD FOSTER ISOLATED STORMS BY 00Z.
DEEP-LAYER SPEED SHEAR WILL BE STRONG AND SUFFICIENT FOR PRODUCTION
OF SEVERE HAIL IN INITIAL UPDRAFTS. WITH TIME...THE INCREASINGLY
UNDERCUTTING NATURE OF THE COLD FRONT SHOULD EVOLVE PRIMARY
CONVECTIVE DEVELOPMENT ON THE COOL SIDE OF THE BOUNDARY. THIS ALONG
WITH PROGRESSIVELY WEAKER LAPSE RATES WITH ERN EXTENT SHOULD RENDER
A PREDOMINANTLY MARGINAL HAIL/WIND RISK AS THE FRONT APPROACHES THE
GULF COAST.

..GRAMS/COHEN.. 10/18/2013

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