Mesoscale Discussion 737

MESOSCALE DISCUSSION 0737
NWS STORM PREDICTION CENTER NORMAN OK
0643 PM CDT FRI APR 25 2008
AREAS AFFECTED...ERN WI...NRN LOWER MI
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 252343Z - 260115Z
THE SEVERE THREAT WILL LIKELY INCREASE EWD FROM FAR ERN WI ACROSS
NRN LAKE MICHIGAN INTO NRN LOWER MI EARLY THIS EVENING. AN ISOLATED
TORNADO THREAT MAY EXIST OVER THE NEXT HOUR IN FAR ERN WI WITH A
THREAT FOR LARGE HAIL AND ISOLATED WIND DAMAGE DEVELOPING ACROSS NRN
LOWER MI. A WW MAY BECOME NECESSARY ACROSS THE REGION.
LATEST SFC ANALYSIS SHOWS A DEEPENING 997 MB SFC LOW OVER WRN WI
WITH A WARM FRONT ADVANCING NWD ACROSS NRN WI. A 30 TO 40 KT JET
NEAR 850 MB IS LOCATED ACROSS NRN IL AND ERN WI AND THIS FEATURE IS
CREATING STRONG LOW-LEVEL SHEAR ACROSS THE REGION. GREEN BAYS
WSR-88D VWP CURRENTLY SHOWS ABOUT 30 KT OF 0-1KM SHEAR SUGGESTING
THE LOW-LEVEL SHEAR ENVIRONMENT MAY SUPPORT AN ISOLATED TORNADO
THREAT FOR ANOTHER HOUR OR SO. FURTHER EAST ACROSS NRN LOWER
MI...SFC DEWPOINTS ARE NEAR 60 F AND SBCAPE VALUES ARE IN THE 2000
TO 2500 J/KG RANGE ON THE EAST SIDE OF LAKE MICHIGAN. THIS ALONG
WITH 40 TO 45 KT OF 0-6 KM SHEAR EVIDENT ON THE LATEST WSR-88D VWPS
SUGGEST A SEVERE THREAT SHOULD DEVELOP OVER THE NEXT 1 TO 2 HOURS.
LARGE HAIL AND ISOLATED WIND DAMAGE WOULD LIKELY BE THE PRIMARY
THREATS.
..BROYLES.. 04/25/2008