DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 100558
SWODY2
SPC AC 100556

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CDT THU MAY 10 2007

VALID 111200Z - 121200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN SD AND SW
MN...

..NRN PLAINS AND NRN HIGH PLAINS...
AN UPPER-LEVEL RIDGE OVER THE SRN AND CNTRL ROCKIES WILL CONTINUE TO
AMPLIFY TONIGHT INTO FRIDAY SHIFTING THE WESTERLIES NWD INTO THE NRN
PLAINS. MODEL FORECASTS ARE IN GENERAL AGREEMENT BRINGING A SUBTLE
SHORTWAVE TROUGH ACROSS THE NRN PLAINS FRIDAY AFTERNOON AND EVENING.
AT THE SFC...A LOW IS FORECAST TO DEVELOP OVER THE NRN HIGH PLAINS
AND MOVE EWD INTO SD FRIDAY AFTERNOON. EAST OF THIS
LOW...INSTABILITY SHOULD DEVELOP AND LOW-LEVEL CONVERGENCE SHOULD
INCREASE DURING THE DAY. THIS COMBINED WITH WEAK LARGE-SCALE ASCENT
ASSOCIATED WITH THE SHORTWAVE TROUGH MAY BE ENOUGH TO INITIATE
ISOLATED THUNDERSTORMS LATE FRIDAY AFTERNOON OR FRIDAY EVENING.
OTHER ISOLATED THUNDERSTORMS MAY INITIATE WWD ALONG THE INSTABILITY
AXIS INTO NRN WY...SERN MT AND INTO PARTS OF THE NRN ROCKIES.

A 55 KT MID-LEVEL JET ASSOCIATED WITH THE SHORTWAVE TROUGH WILL MOVE
ACROSS THE NRN PLAINS FRIDAY AFTERNOON CREATING STRONG VERTICAL
SHEAR PROFILES ACROSS SD AND WRN MN. IN ADDITION...FORECAST
SOUNDINGS LATE FRIDAY AFTERNOON INTO THE EVENING SHOW STEEP
MID-LEVEL LAPSE RATES IN PLACE ACROSS THE SLIGHT RISK AREA. THIS
ENVIRONMENT WILL BE FAVORABLE FOR ISOLATED SUPERCELLS CAPABLE OF
LARGE HAIL AND ISOLATED STRONG WIND GUSTS. HOWEVER...STORM COVERAGE
SHOULD REMAIN ISOLATED AND THE EXTENT OF THE THREAT REMAINS
CONDITIONAL ATTM.

..LOWER MS VALLEY...
AN UPPER-LEVEL LOW OVER EAST TX IS FORECAST TO WEAKEN TONIGHT. AT
LOW-LEVELS...ABUNDANT MOISTURE WILL BE IN PLACE ACROSS THE LOWER MS
VALLEY FRIDAY AND POCKETS OF MODERATE INSTABILITY SHOULD DEVELOP BY
AFTERNOON. ALTHOUGH FORECAST SOUNDINGS ACROSS THE REGION FRIDAY
AFTERNOON SHOW RELATIVELY WEAK VERTICAL SHEAR PROFILES...THE
INSTABILITY SHOULD BE ENOUGH FOR A FEW MARGINALLY SEVERE STORMS
MAINLY CONCENTRATED NEAR PEAK HEATING.

.BROYLES.. 05/10/2007

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