Severe Thunderstorm Warning 1, NWS Grand Rapids, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
300 PM EST TUE FEB 9 1999

SEVERE WITH DAMAGING WINDS LOOKS TO BE A REAL THREAT FOR SW MI LATE
THIS AFTERNOON AND EVENING AS SQUALL LINE RACES NE OUT OF WI/IL/MO.
LOSS OF LOW CLOUDS HAS DESTABALIZED THE AIR MASS AHEAD OF THE FRONT
WITH SFC TEMPS NOW UP NEAR 70 AND DEWPNTS NR 60.  WATCH FROM SPC SEEMS
TO BE A CERTAINTY FOR ALL OF THE FCST AREA AS 100KT MID LVL JET PUNCHES
NEWD AND SURFACE LOW MOVES THROUGH WI AND DEEPENS.

TEMPS DROP ABRUPTLY WITH FROPA SOME 20 TO 30 DEGREES.  THE COLD AIR
QUICKLY UNDERCUTTING THE FRONTAL BOUNDARY HAS RESULTED IN AN EPISODE OF
FRZG RAIN IN PLACES TO OUR WEST TODAY.  WILL ACCOUNT FOR THIS IN THE
FCST FOR LATER TONIGHT HOWEVER NOT EXPECTING FRZG RAIN FOR TOO LONG
SINCE CAA SHOULD BE DEEPER THAN WHAT IS GOING ON TO THE WEST NOW.

DRY SLOTTING AFFECTS THE FCST AREA ON FRI MORNING SO MAY TAKE UNTIL
LATER IN THE DAY TO REALLY GET SOME ORGANIZED SNOW SHOWERS GOING. ALSO
A LOT OF DIRECTIONAL WIND SHEAR PRESENT. DEEPER MOISTURE AND BETTER
INVERSION HEIGHTS ARRIVE ON FRI NGT AND THAT/S WHEN SOME PSBL ACCUMS
WILL BE MENTIONED.

THERMAL TROF MOVES OUT QUICKLY DURING THE DAY SATURDAY PER AVN MODEL AND
SHOULD BRING A DIMINISHING OR ENDING TREND IN THE SNOW SHOWER ACTIVITY.

MEADE

MIZ037>040-043>046-050>052-056>059-064>067-071>074-121200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1125 AM EST THU FEB 11 1999

LATE THIS MORNING A COLD FRONT EXTENDED FROM WESTERN LAKE SUPERIOR
SOUTHWEST TO NEAR KANSAS CITY. AHEAD OF THE COLD FRONT WARM MOIST
AIR WAS FLOWING NORTH FROM THE GULF OF MEXICO. THIS WARM AIR WAS
BOOSTING TEMPERATURES INTO THE MID 60S ACROSS CENTRAL INDIANA.
MEANWHILE...BEHIND THE FRONT...COLD AIR WAS FLOWING SOUTH FROM
CANADA. TEMPERATURES WERE IN THE TEENS IN NORTHWEST MINNESOTA. THE
CLASH OF THE TWO AIR MASSES WAS TRIGGERING THUNDERSTORM ACTIVITY
ALONG THE COLD FRONT.

THIS COLD FRONT WILL MOVE EAST THROUGHOUT THE AFTERNOON AND EVENING
AND MOVE INTO SOUTHWEST LOWER MICHIGAN EARLY THIS EVENING.
THUNDERSTORMS ARE LIKELY WITH THE PASSAGE OF THE FRONT. THERE IS A
SLIGHT RISK SOME OF THESE THUNDERSTORMS COULD BE SEVERE MAINLY SOUTH
OF I-94.

THE THUNDERSTORMS THAT DO FORM WILL MOVE QUICKLY TO THE NORTHEAST AT
45 TO 50 MPH. THE PRIMARY THREAT FROM THESE STORMS WILL BE GUSTY
WINDS. SOME OF THE STORMS COULD PRODUCE WIND GUSTS IN EXCESS OF 60
MPH.

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.
SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND TONIGHT FOR
PARTS OF THE SOUTHWEST QUARTER OF LOWER MICHIGAN.