Severe Thunderstorm Warning 91, NWS Grand Rapids, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
410 PM EDT SAT SEP 8 2001

...MAJOR WAVE ON FRONT COULD BRING HEAVY RAIN SUNDAY...

DUE TO SEVERE WEATHER THIS WILL BE RATHER SHORT.

MODELS AREA REALLY SIMILAR IN SHORT TERM... IN SHORT MAIN WAVE WITH
THE UPPER AIR SYSTEM MOVES THOUGH SOUTHWEST MICHIGAN SUNDAY
AFTERNOON AND EVENING THEN RIDGING FOLLOWS.

I BELIEVE MOST OF THE CONVECTION THIS EVENING WILL END BEFORE
MIDNIGHT AS THE UPPER LEVEL WAVE MOVES EAST OF THE CWA AND THE SFC
HEATING IS GONE.  NEXT PROBLEM WILL BE THE MAIN UPPER SYSTEM
SHEARING OUT TOWARD WESTERN LOWER MICHIGAN SUNDAY.  WHILE THE
INSTABILITY WILL NOT BE AS STRONG AS YESTERDAY OR TODAY... THERE DUE
TO STRONG DYNAMICS ASSOCIATED WITH THE UPPER WAVE INTERACTING WITH
SUBTROPICAL MOISTURE (PRECIPITABLE WATER VALUES NEAR 1.75 INCHES)
AND THE FRONT BEING NEARLY PARALLEL TO THE UPPER FLOW AS THE WAVE
MOVES ALONG... THERE IS A GOOD BET THERE WILL BE VERY HEAVY RAINFALL
OVER MOST OF THE GRR CWA WITH THE HEAVIEST RAIN NORTH AND WEST OF
THE FRONT...MOSTLY NORTH AND WEST OF A LINE FROM BTL TO RQB.  TIMING
GIVES THE HEAVIEST RAINFALL FROM SUNDAY AT18Z TO MONDAY AT 03Z.  DUE
TO FFG BEING IN THE 2 1/2 TO 3 INCH RANGE FOR 3 HOURS...QUESTIONABLE
ABOUT FLOODING BUT NOT OUT OF THE QUESTION.  THE MIDNIGHT SHIFT WILL
HAVE TO LOOK CLOSELY AT THIS.  THE PRECIPITATION WILL END FROM WEST
TO EAST BETWEEN 03Z AND 09Z MONDAY.

TEMPS NEAR FWC MOS.

ZONES BY 430-445 PM.

WDM

EXTENDED FORECAST...
THE MEDIUM RANGE MODELS ARE STILL IN A BIT OF DISAGREEMENT WITH
REGARD TO THE MIDDLE PART OF THE WEEK. WILL SIDE TOWARD THE AVN/MRF
THAT DONT SHOW THE UPR LOW DRIFTING TOWARD THE LAKES ON TUE. WILL
GO WITH A DRY FCST FOR TUE. SFC HIGH WILL BE MOVG IN FROM THE SOUTH
AND SHOULD PROVIDE FOR SOME SUNSHINE. A LOW OVER THE NRN MS VALLEY
WILL PULL A COLD FRONT THRU EARLY WED. DECENT CAA BEHIND THE FRONT
AND A SHORT WAVE DIGGING SE WILL PROVIDE GOOD CONDITIONS FOR CU
DEVELOPMENT DURING THE DAY. WILL WORD AS PT CLDY AND KEEP THE
MENTION OF PM SHOWERS TOO. CANADIAN HIGH PRESSURE WILL THEN CONTROL
THU AND FRIDAY WITH SUNNY DAYS AND CLEAR NIGHTS. ANOTHER WEAK SHORT
WAVE WILL APPROACH FOR THE WEEKEND. WILL WORD AS INCREASING CLOUDS
AND NOT MENTION PCPN YET.

93

.GRR...NONE

MIZ038>040-044>046-051-052-057>059-064>067-071>074-090100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
316 PM EDT SAT SEP 8 2001

THE STORM PREDICTION CENTER HAS ISSUED A FOR PORTIONS OF THE
SOUTHWEST QUARTER OF LOWER MICHIGAN EFFECTIVE UNTIL 900 PM EDT
SATURDAY EVENING. THIS WATCH INCLUDES THE FOLLOWING COUNTIES

IN SOUTH CENTRAL MICHIGAN
     INGHAM...CLINTON...JACKSON...IONIA...CALHOUN AND EATON

IN CENTRAL MICHIGAN
     OSCEOLA...GRATIOT...MONTCALM...MECOSTA...ISABELLA AND CLARE

IN SOUTHWEST MICHIGAN
     KALAMAZOO...KENT...VAN BUREN...BARRY AND ALLEGAN

IN WEST CENTRAL MICHIGAN
     NEWAYGO AND LAKE

THIS WATCH INCLUDES THE ADJOINING COASTAL WATERS OF AFFECTED
LAKESHORE COUNTIES.

A MEANS THAT CONDITIONS ARE FAVORABLE FOR THE DEVELOPMENT OF IN AND
NEAR THE WATCH AREA. REMEMBER...SEVERE THUNDERSTORMS PRODUCE WIND
GUSTS IN EXCESS OF 58 MPH AND/OR HAIL THREE-QUARTERS OF AN INCH IN
DIAMETER OR GREATER. IF YOU LIVE IN OR NEAR THE WATCH AREA YOU SHOULD
REMAIN ALERT TO RAPIDLY CHANGING WEATHER CONDITIONS. STAY TUNED TO
NOAA WEATHER RADIO OR THE LOCAL NEWS OUTLETS FOR THE LATEST UPDATES
AND POSSIBLE WARNINGS.

WDM
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