DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 262002
SWODY1
SPC AC 261959

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0259 PM CDT FRI APR 26 2013

VALID 262000Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON THROUGH
TONIGHT ACROSS MUCH OF OK...

...OK...
THE 1630Z OUTLOOK REMAINS ON TRACK ACROSS OK FOR LATE THIS AFTERNOON
THROUGH TONIGHT...AND THUS NO CHANGES IN SEVERE PROBABILITIES ARE
NEEDED WITH THIS OUTLOOK ISSUANCE. THE 15Z HRRR REMAINS CONSISTENT
WITH EARLIER STORM-SCALE MODEL SOLUTIONS USED IN THE PREVIOUS
OUTLOOK DISCUSSION SUGGESTING INITIALLY MORE DISCRETE STORMS DEVELOP
OVER NWRN INTO CENTRAL OK...WITH THE POTENTIAL FOR ACTIVITY TO GROW
UPSCALE INTO A LINEAR SYSTEM AS THE COLD FRONT MOVES INTO ERN OK
AFTER 27/05Z.

EARLY-MID AFTERNOON SURFACE ANALYSIS SHOWED AN AREA OF LOW PRESSURE
CENTERED OVER THE OK PANHANDLE WITH A FRONT EXTENDING SEWD THROUGH
NWRN TO CENTRAL /N OF KOKC/ AND INTO EAST CENTRAL OK. GIVEN RECENT
BACKING WINDS TO GENERALLY ELY N OF THIS FRONT AND SLY TRAJECTORIES
EXPECTED TO PERSIST OVER SRN OK AHEAD OF THE PROGRESSIVE SURFACE LOW
WOULD SUGGEST THIS BOUNDARY MAY TEND TO BE MORE QUASI-STATIONARY
INTO THIS EVENING. THE LIGHTNING OVER SWRN KS INTO THE NRN TX
PANHANDLE IS INDICATIVE OF THE STRONGER ASCENT ATTENDANT TO THE
SHORTWAVE TROUGH.

..PETERS.. 04/26/2013

.PREV DISCUSSION... /ISSUED 1118 AM CDT FRI APR 26 2013/

...OK...
MORNING WATER VAPOR LOOPS SHOW A WELL-DEFINED SHORTWAVE TROUGH OVER
EASTERN NM AND THE TX PANHANDLE. THIS FEATURE WILL TRACK EASTWARD
AND ACROSS THE SOUTHERN PLAINS TODAY INTO TONIGHT. AHEAD OF THE
TROUGH...SOUTHERLY LOW LEVEL WINDS ARE TRANSPORTING MOISTURE
NORTHWARD ACROSS TX/OK WITH DEWPOINTS RISING THROUGH THE 50S. LOW
CLOUDS ARE SLOWLY ERODING OVER WESTERN OK AND WESTERN NORTH TX...BUT
ARE LIKELY TO PERSIST MOST OF THE DAY OVER THE BULK OF OK. THIS
WILL LIMIT DAYTIME HEATING AND KEEP A SUBSTANTIAL CAPPING INVERSION
IN PLACE THROUGH 00Z.

BY EARLY EVENING...LIFT ASSOCIATED WITH THE NM/TX TROUGH WILL
OVERSPREAD THE MOIST AXIS OVER OK. LARGE SCALE ASCENT WILL LIKELY
RESULT IN A RAPID WEAKENING OF THE CAP AND SCATTERED THUNDERSTORM
DEVELOPMENT OVER NORTHWEST AND CENTRAL OK. FORECAST SOUNDINGS SHOW
STEEP MID LEVEL LAPSE RATES AND ELEVATED MUCAPE VALUES OF 1500+
J/KG. FAVORABLE EFFECTIVE SHEAR VALUES WILL PROMOTE SUPERCELL STORM
STRUCTURES CAPABLE OF HAIL. WHILE DAMAGING WINDS AND TORNADOES ARE
NOT OUT OF THE QUESTION...IT APPEARS THAT LARGE HAIL WILL BE THE
MAIN THREAT TODAY.

THE SUITE OF STORM-SCALE MODEL SOLUTIONS THIS MORNING /NAM
NESTS...NMM...NSSL...HRRR/ SHOW STRONG AGREEMENT IN A NARROW
CORRIDOR OF GREATEST RISK OF SUPERCELL STORMS THIS EVENING AFTER
00Z. THIS AREA OF WESTERN/CENTRAL OK HAVE BEEN INCLUDED IN A 30
PERCENT HAIL RISK.

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