DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 290522
SWODY1
SPC AC 290520

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1220 AM CDT FRI MAR 29 2013

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF ERN TX
PANHANDLE...FAR WRN OK...

...SYNOPSIS...
SYNOPTIC PATTERN WILL CHANGE LITTLE DURING THE PERIOD. IN THE
MEAN...A LOW AMPLITUDE TROUGH WILL PERSIST OVER THE ERN CONUS WITH
AN UPSTREAM RIDGE IN THE WEST. AT THE SURFACE...A LEE TROUGH/DRYLINE
WILL OSCILLATE ACROSS THE CNTRL/SRN HIGH PLAINS...WHILE A WEAK
QUASI-STATIONARY FRONT REMAINS ANCHORED ACROSS PARTS OF OK/AR.

...SRN/CNTRL PLAINS...
ISOLATED TO WIDELY SCATTERED TSTMS THIS AFTERNOON THROUGH TONIGHT
MAY PRODUCE SPORADIC REPORTS OF LARGE HAIL AND SEVERE WIND.
CONFIDENCE IS GENERALLY LOW IN DELINEATING CORRIDORS OF SLIGHT RISK
THREAT...EXCEPT INVOF ERN TX PANHANDLE.

MODEST GULF MOISTURE RETURN WILL CONTINUE IN THE WARM MOIST SECTOR
AHEAD OF THE HIGH PLAINS DRYLINE BENEATH A PRONOUNCED CAPPING
INVERSION /BASE OF THE EML/ SAMPLED IN THU EVENING RAOBS. EVEN WITH
DAYTIME MIXING...AN AXIS OF UPPER 40S TO MIDDLE 50S SURFACE DEW
POINTS SHOULD BE MAINTAINED ACROSS PARTS OF WRN OK/TX. DESPITE
NEAR-NEUTRAL MID-LEVEL HEIGHT CHANGE AND LIKELY ONLY WEAK
CONVERGENCE INVOF THE DRYLINE...A ZONE OF DEEP MIXING JUST BEHIND
THE DRYLINE MAY SUFFICIENTLY WEAKEN THE CAPPING INVERSION ALONG IT.
STRENGTH OF THE CAP WITH ERN EXTENT IN THE WARM/MOIST SECTOR
INCREASES UNCERTAINTY REGARDING DEGREE/SUSTAINABILITY OF STORM
COVERAGE. BEST CHANCE FOR MORE THAN JUST ISOLATED COVERAGE MAY EXIST
INVOF THE DRYLINE/STATIONARY FRONT INTERSECTION. MODERATE DEEP-LAYER
SHEAR ALONG WITH STEEP MID-LEVEL LAPSE RATES YIELDING MLCAPE OF
1000-1500 J/KG MAY SUPPORT A FEW SUPERCELLS PRODUCING LARGE HAIL AND
SEVERE WINDS. MODEST EVENING LLJ RESPONSE IN THE PLAINS MAY SUSTAIN
A COUPLE OF STRONG TO MARGINALLY SEVERE CLUSTERS TONIGHT.

..GRAMS.. 03/29/2013

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