SPC AC 131601
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1101 AM CDT FRI JUN 13 2008
VALID 131630Z - 141200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM LWR MI AND THE LWR OH
VALLEY SW INTO THE OZARKS/SRN PLAINS......
...SYNOPSIS...
UNSEASONABLY STRONG UPPER LEVEL LOW WILL BE SHIFTING NEWD OUT OF
NCNTRL U.S. INTO WRN ONTARIO THIS FORECAST PERIOD. THERE IS STILL A
ANOTHER MID LEVEL WIND MAX ROTATING EWD TO S OF LOW CIRCULATION THAT
TRACKS ENEWD ACROSS MID MS VALLEY THIS AFTERNOON AND ACROSS GREAT
LAKES OVERNIGHT.
OVERNIGHT CONVECTION HAS MASKED LOCATION OF COLD FRONT AND PROVIDED
THE EFFECTIVE BOUNDARIES FOR TODAYS MORE ORGANIZED SEVERE THREAT.
PRIMARY OUTFLOW BOUNDARY SEPARATING THE VERY MOIST/MODERATELY
UNSTABLE AIR AND THE CONVECTIVELY STABILIZED AIR MASS EXTENDS FROM
NERN IL SWD INTO SRN MO AND NRN OK.
...OH VALLEY INTO GREAT LAKES...
AREA AHEAD OF OUTFLOW BOUNDARIES FROM IND INTO SRN MI IS RAPIDLY
DESTABILIZING AHEAD OF MID LEVEL WIND MAX WITH LITTLE REMAINING
CINH. THUNDERSTORMS WILL INCREASE IN NUMBER AND INTENSITY ALONG AND
AHEAD OF SURFACE CONVERGENCE FROM CENTRAL IL NEWD INTO SRN LOWER MI
THRU EARLY/MID AFTERNOON. DEEP LAYER SHEAR OF 35-40KT WILL SUPPORT
PRIMARY MULTICELLULAR STORMS EVOLVING INTO LINE SEGMENTS/BOWS AS
COLD POOLS DEVELOP DURING THE AFTERNOON. HOWEVER WITH MLCAPES AOA
2000 J/KG THERE WILL BE POTENTIAL FOR SUPERCELLS WITH AN ENHANCED
SEVERE THREAT OF BOTH WINDS/HAIL AND ISOLATED TORNADOES INTO THE
EVENING HOURS. WHILE STRONG THUNDERSTORMS WILL CONTINUE INTO THE
NIGHT EWD ACROSS THE OH AND TN VALLEYS...SEVERE THREAT WILL
GRADUALLY DIMINISH BY LATE EVENING WITH LOSS OF SURFACE HEATING.
...MID MS VALLEY TO SRN PLAINS...
WHILE SHEAR WILL BE SOMEWHAT WEAKER IN ADVANCE OF SLOWLY MOVING
BOUNDARIES THAT EXTENDS WWD ACROSS NRN OK...THE AIR MASS WILL BE
MODERATELY UNSTABLE AND WEAKLY CAPPED BY MID AFTERNOON. SEVERE
THUNDERSTORMS SHOULD DEVELOP ALONG/AHEAD OF BOUNDARIES WWD AS FAR AS
CENTRAL OK BY THIS EVENING. STEEPER MID LEVEL LAPSE RATES COUPLED
WITH MLCAPES AOA 2500 J/KG SUPPORT NOT ONLY LARGE HAIL BUT DAMAGING
DOWNBURST WINDS.
...NRN/ERN MT INTO WRN ND...
SFC HEATING BENEATH COOL CYCLONIC FLOW ON SWRN FRINGE OF MANITOBA
LOW...AND ASCENT ASSOCIATED WITH UPR IMPULSE NOW ENTERING NW MT...
SHOULD SUPPORT SCTD DIURNAL STORMS FROM NRN/ERN MT INTO WRN ND LATER
TODAY. COMBINATION OF MODERATE...DEEP UNIDIRECTIONAL WNWLY FLOW AND
STEEP LOW- TO MID-LVL LAPSE RATES MAY YIELD A FEW SPOTS OF LOCALLY
DMGG WIND AND MARGINALLY SVR HAIL.
..HALES/BOTHWELL.. 06/13/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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