SPC AC 080558
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1158 PM CST MON JAN 07 2008
VALID 081200Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MS VALLEY AND LOWER
OH VALLEY...
...MS VALLEY/LOWER OH VALLEY...
LATEST WATER VAPOR IMAGERY SHOWS A BROAD OPEN UPPER-LEVEL TROUGH
OVER THE ROCKIES WITH SOUTHWEST FLOW IN PLACE ACROSS THE MS AND OH
VALLEYS. A SERIES OF SHORTWAVE TROUGHS ARE EMBEDDED IN THE FLOW
ACROSS THE SRN PLAINS AND MID-MS VALLEY. A SFC LOW LOCATED ACROSS
THE SRN PLAINS WILL MOVE QUICKLY NEWD TODAY INTO THE GREAT LAKES
REGION AS A COLD FRONT SWEEPS SEWD ACROSS THE MS VALLEY. SEVERAL
SYNOPTIC-SCALE LINES OF THUNDERSTORMS WILL LIKELY BE ONGOING ALONG
AND JUST AHEAD OF THE FRONT THIS MORNING. SOME DECREASE IN COVERAGE
AND INTENSITY MAY OCCUR BEFORE MIDDAY BUT AS INSTABILITY INCREASES
THUNDERSTORMS SHOULD REORGANIZE DURING THE AFTERNOON. THE LINE OF
STORMS SHOULD MOVE EWD REACHING IND...WRN KY...WRN TN AND MS BY
EARLY EVENING.
CONCERNING THE SEVERE POTENTIAL...THE SHEAR ENVIRONMENT WILL REMAIN
STRONG ACROSS THE REGION AS AN 80 KT MID-LEVEL JET PASSES OVERHEAD
ASSOCIATED WITH THE UPPER-LEVEL TROUGH. ALTHOUGH THE SHEAR WILL BE
SUFFICIENT FOR ORGANIZED SEVERE STORMS...THE AMOUNT OF INSTABILITY
FORECAST IS MUCH LESS THAN THE PREVIOUS DAY. THIS SHOULD CONCENTRATE
MOST OF THE SEVERE WEATHER THREAT IN THE LATE AFTERNOON AND EARLY
EVENING WHEN INSTABILITY WILL BE MAXIMIZED. IN ADDITION...MODEL
FORECASTS VEER LOW-LEVEL WINDS ALONG AND AHEAD OF THE FRONT
SUGGESTING THE TORNADO THREAT WILL NOT BE AS HIGH TODAY WITH WIND
DAMAGE THE GREATER THREAT. WIND DAMAGE WILL BE POSSIBLE WITH THE
FASTER MOVING BOWING LINE SEGMENTS. AN ENHANCED WIND DAMAGE THREAT
MAY EXIST IN THE LATE AFTERNOON FROM FAR SRN IL SSWWD INTO NW MS
WHERE THE COMBINATION OF INSTABILITY AND LOW-LEVEL FLOW SHOULD BE
THE GREATEST. SUPERCELLS EMBEDDED IN THE LINE MAY ALSO HAVE HAIL
POTENTIAL. THE GREATEST SUPERCELL THREAT WILL LIKELY EXIST ACROSS
THE SRN HALF OF THE SLIGHT RISK AREA WHERE SFC DEWPOINTS SHOULD BE
IN THE LOWER 60S F. IF A SQUALL-LINE CAN ORGANIZE THIS AFTERNOON...A
WIND DAMAGE THREAT MAY CONTINUE INTO THE EVENING ACROSS FAR SW
OH...CNTRL KY...MIDDLE TN AND NE MS. HOWEVER...A RAPID DECREASE IN
SEVERE THREAT COVERAGE SHOULD OCCUR BY LATE EVENING AS INSTABILITY
WEAKENS ACROSS THE REGION.
..BROYLES.. 01/08/2008
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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