SPC AC 240558
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT MON SEP 24 2007
VALID 251200Z - 261200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE
MIDWEST/UPPER GREAT LAKES REGION...
...SYNOPSIS...
UPPER SHORT-WAVE TROUGH WILL CONTINUE MOVING ENEWD ACROSS THE N
CENTRAL CONUS...AND SHOULD CROSS THE UPPER GREAT LAKES/ONTARIO
DURING THE SECOND HALF OF THE PERIOD. THE ASSOCIATED COLD FRONT --
INITIALLY FORECAST FROM THE WRN UPPER GREAT LAKES SWWD ACROSS THE
MID MO VALLEY/ERN KS/OK AND INTO ERN NM -- WILL ALSO PROGRESS
STEADILY EWD/SEWD. BY THE END OF THE PERIOD...THIS FRONT SHOULD
EXTEND FROM ERN LOWER MI/NWRN OH SWWD ACROSS THE MID MS VALLEY INTO
CENTRAL TX.
...LOWER MI INTO PARTS OF IL/INDIANA/NWRN OH...
SHOWERS AND THUNDERSTORMS SHOULD BE ONGOING AT THE START OF THE
PERIOD FROM WI SWWD INTO THE PLAINS...INVOF COLD FRONT PROGRESSING
EWD/SEWD ACROSS THIS REGION. CONVECTION WILL LIKELY INCREASE IN
COVERAGE ALONG THE LENGTH OF THE FRONT BY AFTERNOON...AS MOIST WARM
SECTOR AND DIURNAL HEATING RESULT IN WIDESPREAD 500 TO 1000 J/KG
MIXED-LAYER CAPE.
WHILE WEAK FLOW ALOFT ATOP THE WARM SECTOR FROM ROUGHLY OK SWWD
SUGGESTS LITTLE IF ANY SEVERE THREAT...THREAT IS FORECAST TO
INCREASE NEWD ACROSS MO -- AND PARTICULARLY INTO PARTS OF IL/IN AND
INTO LOWER MI -- WHERE 40 TO 50 KT SWLYS AT MID LEVELS SPREAD ACROSS
THE SURFACE FRONTAL ZONE. WHILE SHEAR WILL BE SUFFICIENT FOR
SUPERCELLS...STORM MODE SHOULD BE PRIMARILY LINEAR -- WITH A THREAT
FOR DAMAGING WINDS APPARENT GIVEN MODERATELY-STRONG/ROUGHLY
UNIDIRECTIONAL FLOW FORECAST THROUGH THE LOWER AND MIDDLE
TROPOSPHERE.
WHILE A DIURNAL DECREASE IN THREAT IS EXPECTED OVERNIGHT...SOME
SEVERE POTENTIAL MAY LINGER THROUGH THE END OF THE PERIOD.
..GOSS.. 09/24/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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