SPC AC 240559
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT SUN JUN 24 2007
VALID 251200Z - 261200Z
...THERE IS A SLGT RISK OF SVR TSTMS NRN PLAINS...
...SYNOPSIS...
MAIN UPPER FEATURE WITH RESPECT TO THE CONVECTIVE FORECAST THIS
PERIOD WILL BE AN UPPER TROUGH OVER THE NWRN CONUS AT THE START OF
THE PERIOD. THIS FEATURE IS FORECAST TO EVOLVE INTO A CLOSED
LOW...AND MOVE SLOWLY ENEWD INTO SRN SASKATCHEWAN BY THE END OF THE
PERIOD.
AT THE SURFACE...A COLD FRONT IS FORECAST TO MOVE OUT OF THE NRN
PLAINS THROUGH THE AFTERNOON...AND SHOULD CROSS THE DAKOTAS AND
REACH MN BY 16/12Z. THIS FRONT SHOULD SERVE AS A FOCUS FOR SEVERE
STORM DEVELOPMENT DURING THE AFTERNOON AND EVENING.
...THE DAKOTAS INTO NWRN MN...
STORMS SHOULD BE ONGOING OVER PARTS OF THE NRN PLAINS AT THE START
OF THE PERIOD...WITHIN ZONE OF WARM ADVECTION ASSOCIATED WITH
WEAKENING NOCTURNAL LOW-LEVEL JET.
CONVECTIVE REDEVELOPMENT IS FORECAST DURING THE AFTERNOON...AS COLD
FRONT MOVING OUT OF MT/WY IMPINGES ON MODERATELY-UNSTABLE AIRMASS
ALLOWING CAP TO WEAKEN WITH TIME. SWD EXTENT OF STORM INITIATION IS
UNCLEAR...WITH CAP LIKELY TO REMAIN IN PLACE FROM CENTRAL SD SWD.
STORMS WHICH DO DEVELOP SHOULD BECOME SUPERCELLULAR...AS 40 TO 50 KT
SWLY MID-LEVEL FLOW SPREADS EWD OUT OF THE NRN ROCKIES ABOVE
LOW-LEVEL SLYS. THUS -- EXPECT POTENTIAL FOR VERY LARGE HAIL AND
LOCALLY-DAMAGING WINDS. IN ADDITION...SOME THREAT FOR ISOLATED
TORNADOES MAY EVOLVE ACROSS PARTS OF ND AND POSSIBLY INTO NWRN
MN...WHERE GREATER LOW-LEVEL VEERING IS FORECAST ON NERN FRINGES OF
NEWD-MOVING SURFACE LOW.
...SRN HIGH PLAINS...
ISOLATED THUNDERSTORMS ARE FORECAST TO DEVELOP -- MAINLY OVER THE
SRN HIGH PLAINS -- AS MODEST INSTABILITY DEVELOPS. WITH 25 TO 30 KT
NLY MID-LEVEL FLOW FORECAST ACROSS THIS REGION...A FEW ORGANIZED
CELLS MAY EVOLVE BY LATE AFTERNOON...CAPABLE OF PRODUCING HAIL OR
LOCALLY GUSTY WINDS.
..GOSS.. 06/24/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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