DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 100729
SWODY3
SPC AC 100728

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT THU MAY 10 2007

VALID 121200Z - 131200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN ROCKIES
AND NRN HIGH PLAINS...

..NRN ROCKIES/NRN HIGH PLAINS...
AN UPPER-LEVEL RIDGE OVER THE CNTRL ROCKIES AND NRN HIGH PLAINS WILL
REMAIN IN PLACE THROUGH SATURDAY AS AN UPPER-LEVEL TROUGH MOVES EWD
TOWARD THE WEST COAST. SWLY FLOW ALOFT AHEAD OF THE TROUGH WILL
OVERSPREAD THE NRN ROCKIES AND LARGE-SCALE ASCENT WILL INCREASE AS A
SFC LOW DEVELOPS ACROSS THE REGION. DUE TO THESE FACTORS...SCATTERED
THUNDERSTORMS SHOULD INITIATE IN THE NRN ROCKIES SATURDAY AFTERNOON
WITH STORM COVERAGE GRADUALLY EXPANDING. FORECAST SOUNDINGS ACROSS
THE REGION SATURDAY AFTERNOON SHOW STRONG VERTICAL SHEAR PROFILES
AND STEEP MID-LEVEL LAPSE RATES WHICH SHOULD BE SUFFICIENT FOR AN
ISOLATED SEVERE THREAT. THE THREAT FOR HAIL AND STRONG GUSTY WINDS
SHOULD BE GREATEST IN THE LATE AFTERNOON AND EARLY EVENING.

..NRN PLAINS AND UPPER MIDWEST...
AN UPPER-LEVEL RIDGE WILL REMAIN IN PLACE ACROSS THE CNTRL ROCKIES
AND NRN HIGH PLAINS THROUGH SATURDAY. AT LOWER LEVELS...A FRONTAL
BOUNDARY SHOULD EXIST FROM THE CNTRL HIGH PLAINS EXTENDING EWD INTO
THE UPPER MIDWEST. ALTHOUGH A CAPPING INVERSION IS FORECAST TO BE IN
PLACE...INSTABILITY ALONG AND SOUTH OF THE BOUNDARY AND CONVERGENCE
ALONG THE BOUNDARY ITSELF...MAY ALLOW FOR ISOLATED THUNDERSTORM
DEVELOPMENT BY SATURDAY EVENING. IN ADDITION...FORECAST SOUNDINGS
SHOW MODERATE VERTICAL SHEAR PROFILES ACROSS THE REGION WHICH MAY BE
SUFFICIENT FOR AN ISOLATED SEVERE THREAT WHERE CONVECTION DEVELOPS.
IT IS TOO EARLY TO PINPOINT WHERE CONVECTION WILL BE MOST PROBABLE.
ONCE CERTAINTY INCREASES CONCERNING CONVECTIVE INITIATION...AN
UPGRADE TO SLIGHT RISK MAY BECOME NECESSARY ACROSS PARTS OF THE
REGION.

..ERN GULF COAST STATES/ATLANTIC COASTAL PLAINS...
ABUNDANT LOW-LEVEL MOISTURE WILL BE IN PLACE ACROSS THE SERN STATES
SATURDAY AND MODEL FORECASTS DEVELOP POCKETS OF MODERATE INSTABILITY
ACROSS THE REGION SATURDAY AFTERNOON. ALTHOUGH VERTICAL SHEAR
PROFILES ARE FORECAST TO BE RELATIVELY WEAK SATURDAY...THUNDERSTORM
COVERAGE AND INSTABILITY MAY BE GREAT ENOUGH FOR A MARGINAL SEVERE
THREAT. ANY MARGINAL THREAT SHOULD BE SHORT-LIVED AND CONCENTRATED
AROUND PEAK HEATING SATURDAY AFTERNOON.

.BROYLES.. 05/10/2007

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