DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 281730
SWODY2
SPC AC 281729

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CDT THU MAR 28 2013

VALID 291200Z - 301200Z

...NO SVR TSTM AREAS FORECAST...

...SRN AND CNTRL PLAINS...
AN UPPER-LEVEL RIDGE OVER THE ROCKIES LATE TONIGHT IS FORECAST TO
BUILD WWD ACROSS THE INTERMOUNTAIN WEST ON FRIDAY AS NORTHWEST FLOW
BECOMES MORE FIRMLY ESTABLISHED ACROSS THE GREAT PLAINS. AT THE
SFC...A LOW IS FORECAST TO DEVELOP ACROSS WEST TX ON FRIDAY AS A
STATIONARY FRONT REMAINS IN PLACE FROM THE TX PANHANDLE EXTENDING
NEWD ACROSS NW OK AND SE KS. IN SPITE OF SLY FLOW ACROSS THE SRN
PLAINS FRIDAY...SFC DEWPOINTS ONLY FORECAST TO REACH THE LOWER TO
MID 50S F ACROSS MUCH OF THE SRN PLAINS. DUE TO THIS FACTOR...SFC
HEATING SHOULD KEEP THE STRONGEST DESTABILIZATION CONFINED TO WEST
TX AND WRN OK WHERE MID-LEVEL LAPSE RATES SHOULD BE VERY STEEP. AS A
CAPPING INVERSION WEAKENS DURING THE AFTERNOON...THE MODELS SUGGEST
SOME THUNDERSTORMS WILL INITIATE FROM WEST TX NNEWD ACROSS WRN OK
INTO SRN KS. THE UPPER-LEVEL RIDGE TO THE WEST SHOULD KEEP
LARGE-SCALE ASCENT LIMITED...HELPING TO KEEP CONVECTIVE COVERAGE
ISOLATED. THE MOST FAVORABLE AREA FOR STORM DEVELOPMENT COULD BE
ACROSS THE LOW-ROLLING PLAINS OF WEST TX WHERE THE MODELS DEVELOP
THE MOST INSTABILITY AND WHERE LOW-LEVEL FLOW SHOULD BECOME ENHANCED
DURING THE EARLY EVENING.

NAM FORECAST SOUNDINGS NEAR LUBBOCK AND CHILDRESS AT 00Z/SAT SHOW
MLCAPE VALUES PEAKING NEAR 1500 J/KG ACCENTUATED BY STEEP MID-LEVEL
LAPSE RATES. 0-6 KM SHEAR IS FORECAST TO BE NEAR 40 KT ASSOCIATED
WITH SPEED SHEAR IN THE MID-LEVELS. THE INSTABILITY AND SHEAR
COMBINED WITH 700 TO 500 LAPSE RATES AROUND 8.0 C/KM COULD BE ENOUGH
FOR A HAIL THREAT ASSOCIATED WITH STORMS THAT DEVELOP ROTATION.
ALTHOUGH...THERE IS THE POTENTIAL FOR ISOLATED LARGE HAIL...THE
MESOSCALE SETUP REMAINS TOO UNCLEAR TO FORECAST WHERE THE GREATEST
SEVERE THREAT WILL BE. FOR THIS REASON...WILL KEEP THE SEVERE
PROBABILITIES LOW ATTM. A LOW-END SEVERE THREAT COULD EXTEND AS FAR
EAST AS THE MTNS OF ERN OK WHERE MODEL FORECASTS DEVELOP WEAK
INSTABILITY AND SHOW ENOUGH SHEAR FOR A MARGINAL SEVERE THREAT.

FURTHER TO THE NORTH ACROSS WRN KS AND FAR SE CO...FORECAST
SOUNDINGS SHOW DEWPOINTS IN THE 40S F WITH MLCAPE VALUES PEAKING
AROUND 1000 J/KG LATE FRIDAY AFTERNOON. THIS ALONG WITH STEEP
MID-LEVEL LAPSE RATES COULD BE ENOUGH FOR HAIL AS CELLS MATURE AND
MOVE OUT INTO THE CNTRL HIGH PLAINS. AGAIN...THE RELATIVELY DRY
BOUNDARY LAYER IS EXPECTED TO LIMIT SEVERE THREAT COVERAGE BUT A FEW
OF THE STRONGER CELLS COULD HAVE A POTENTIAL FOR STRONG WIND GUSTS
AND HAIL.

..BROYLES.. 03/28/2013

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