Hail and Damaging Wind in Michigan, May 30 to 31, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1140 AM EDT THU MAY 30 2002

LATEST SURFACE ANALYSIS INDICATING STATIONARY FRONTAL BOUNDARY JUST
NORTH OF LAKE SUPERIOR. AREA OF LOW SURFACE PRESSURE CENTERED OVER
LAKE WINNIPEG WITH SURFACE TROUGH NOW MOVING THROUGH MINNESOTA.
LITTLE IN THE WAY OF LOW LEVEL BOUNDARIES ANALYZED WITHIN THE
STATE...BUT PERHAPS A WEAK TROUGH EXTENDING FROM WISCONSIN INTO
SOUTHWEST LOWER MICHIGAN. SURFACE DEWPOINTS NOW INTO THE LOWER 60S
IN NORTHERN LOWER MICHIGAN AND MID TO UPPER 50S IN EASTERN UPPER
MICHIGAN.

12Z UPPER AIR CHARTS AND WATER VAPOR IMAGERY REVEALING MAIN
SHORTWAVE CENTER AND MOVING INTO WESTERN LAKE SUPERIOR WITH SHEAR
AXIS EXTENDING SOUTH THROUGH WISCONSIN. WEAKER VORTICITY CENTER
PERHAPS PRESENT MOVING INTO SOUTHERN LAKE MICHIGAN. 850/700/500 MB
TROUGH AXES NEARLY COINCIDENT THROUGH WESTERN WISCONSIN AND (ALONG
WITH MID LEVEL SHORTWAVE) THE MAIN DRIVING FORCE FOR LINE OF
THUNDERSTORMS MOVING INTO CENTRAL UPPER MICHIGAN.

FORECAST CONCERNS FOR THE AFTERNOON AND EVENING ARE WITH
THUNDERSTORMS AND POTENTIAL FOR SEVERE WEATHER.

LOW AND MID LEVEL TROUGH AXIS WILL SLIDE INTO NORTHERN LOWER AND
EASTERN UPPER MICHIGAN BY MID TO LATE AFTERNOON...WHILE STRONGEST
FORCING MOVES THROUGH THE NORTH WITH THE MAIN VORTICITY CENTER. NO
REAL LOW LEVEL BOUNDARIES TO INITIATE CONVECTION ALONE...SO WILL
HAVE TO WAIT UNTIL DYNAMIC FORCING THIS AFTERNOON TO INITIATE
CONVECTION. WILL CONTINUE LIKELY TO CATEGORICAL SHOWER AND
THUNDERSTORM WORDING FOR THE AFTERNOON.

AS FAR AS CONVECTIVE PARAMETERS ARE CONCERNED. MODIFIED 12Z APX
SOUNDING FOR 77/61 YIELDING CAPES AROUND 2000 J/KG AND LI/S AROUND
-5C. HOWEVER...WIND FIELDS REMAIN VERY WEAK THROUGH THE AFTERNOON
WITH WINDS 25 KNOTS OR LESS THROUGH 500 MB. THUS...VERY LITTLE SHEAR
TO AID SUSTAINED UPDRAFTS OR AVAILABLE TO MIX DOWN. FREEZING LEVELS
AND WET BULB ZEROS ALSO RUNNING HIGH (>10500 FEET) THUS HAIL THREAT
ALSO MINIMAL FOR THIS AFTERNOON.

THINGS CHANGE THIS EVENING HOWEVER. LOW AND MID LEVEL WIND FIELDS
INCREASE EARLY THIS EVENING WITH BULK SHEAR VALUES INCREASING TO
NEAR 40 KNOTS AS SURFACE TROUGH PUSHES THROUGH THE REGION. LOW
LEVELS WILL REMAIN QUITE MOIST SO ALTHOUGH TROUGH COMES THROUGH
OUTSIDE OF PEAK HEATING...LOW LEVEL INSTABILITY WILL REMAIN QUITE
HIGH. SO...BEST TIME FOR SEVERE WEATHER THREAT APPEARS TO BE THIS
EVENING/EARLY OVERNIGHT BETWEEN 02Z AND 08Z AND FOR LOCATIONS
PRIMARILY IN EASTERN UPPER MICHIGAN AND FAR NORTHERN LOWER
MICHIGAN...WITH PRIMARY THREAT DAMAGING WIND GUSTS. WILL UPDATE
HAZARDOUS WEATHER OUTLOOK ACCORDINGLY.

OTHERWISE...WILL TAKE A LOOK AT 11 AM OBS AND TWEAK TEMPS/WINDS
ACCORDINGLY.

.APX...NONE.

ADAM

MIZ008-015>036-041-042-302000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GAYLORD MI
1145 AM EDT THU MAY 30 2002

...SEVERE WEATHER POSSIBLE TONIGHT...

* THREAT AREA...EASTERN UPPER MICHIGAN AND NORTHERN LOWER
  MICHIGAN PRIMARILY NORTH OF M-72.

* DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

* HAZARDOUS WEATHER THREAT...THUNDERSTORM WINDS OF 60 MPH AND/OR
  HAIL UP TO ONE INCH IN DIAMETER.

* TIME OF HAZARDOUS WEATHER THREAT...FROM 9 PM THROUGH 3 AM.

* FOR INFORMATION REGARDING ONGOING...POSSIBLY HAZARDOUS...WEATHER
  CONDITIONS PLEASE REFER TO WWW.CRH.NOAA.GOV/APX/ (ALL LOWER CASE).

IF LATER INFORMATION FURTHER SUPPORTS THIS HAZARDOUS WEATHER
THREAT...APPROPRIATE WATCHES AND/OR WARNINGS WILL BE ISSUED. STAY
TUNED TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA FOR THE LATEST
WEATHER INFORMATION.

ADAM