FXUS63 KGRR 241941
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
340 PM EDT SUN AUG 24 2003 

SKIES CONTINUE CLEAR THIS AFTERNOON ACROSS SOUTHWEST LOWER
MICHIGAN...SO WILL START THE EVENING OFF MOSTLY CLEAR.  
THE ATMOSPHERE UPSTREAM CONTINUES TO DESTABILIZE ACROSS
SOUTHERN MINNESOTA AND WISCONSIN.  A SHORTWAVE OVER NORTHERN
MINNESOTA IS FORECASTED TO DROP EAST SOUTHEAST OVERNIGHT
INTO LOWER MICHIGAN...WITH ELEVATED INSTABILITY IN PLACE.
AM EXPECTING AN AREA OF STORMS TO DEVELOP ACROSS MINNESOTA
THIS EVENING...THEN TRACK EAST SOUTHEAST...PERHAPS MOVING
INTO SOUTHWEST LOWER MICHIGAN TOWARD MIDNIGHT.  WILL
INCREASE PROBABILITIES TONIGHT SLIGHTLY...AND TIME
THE PRECIPITATION...MAINLY AFTER EVENING. 

WHILE THERE STILL MAY BE A FEW SHOWERS OR STORMS AROUND
INTERSTATE 94 TO START THE DAY ON MONDAY...THE BULK
OF THE TIME IS EXPECTED TO BE DRY.  WITH DEBRIS CLOUDS
DISSIPATING LEADING TO INCREASING SUNSHINE...MANY
AREAS SHOULD SEE TEMPERATURES CLIMB BACK INTO THE 80S.

AN ACTIVE NIGHT IS EXPECTED MONDAY NIGHT.  THE WARM 
FRONT RETURNS.  ALOFT THE 250 MB JET IS DIFFLUENT AND
ANTICYCLONICALLY CURVED.  DOWN BELOW...HIGH PRECIPITABLE
WATER AIR IS BEING ADVECTED IN ON  A 30 TO 40 KNOT 850 
JET.  HEAVY RAIN AND SEVERE WEATHER COULD OCCUR.  HPC
INCREASED RAINFALL AMOUNTS AND THE SLIGHT RISK AREA HAS
BEEN EXPANDED TO INCLUDE ALL OF SOUTHWEST LOWER MICHIGAN.

WITH A MOIST AND UNSTABLE AIRMASS IN PLACE FOR TUESDAY
AND TUESDAY NIGHT...WILL CONTINUE TO MENTION SOME STORMS.
STRONG WINDS AT THE MID AND UPPER LEVELS OF THE ATMOSPHERE
COULD LEAD TO ADDITIONAL SEVERE WEATHER.  THE SLIGHT RISK
CONTINUES ACROSS THE ENTIRE AREA.  

FOR WED...A MORE STABLE AIRMASS IS EXPECTED TO DROP DOWN FROM
THE NORTH.   WILL CONTINUE TO DRY THE WEATHER OUT.

MJS

EXTENDED FORECAST DISCUSSION...
THE WEATHER LOOKS LIKE IT WILL START OUT DRY FOR THE BEGINNING OF 
THE EXTENDED FORECAST ON WEDNESDAY NIGHT. THE COLD FRONT THAT IS 
EXPECTED TO PASS SOUTH OF THE AREA LATE TUE WILL STILL BE LOCATED 
FAR ENOUGH SOUTH TO KEEP THE AREA DRY. THE MODELS ARE HAVING SOME 
DIFFICULTY WITH THE TIMING OF THIS FRONT RIDING BACK NORTH AS A WARM 
FRONT. THE SLOWER GFS SOLUTION IS THE PREFERRED WAY TO GO DUE TO THE 
ORIENTATION OF THE UPPER FLOW AS COMPARED TO THE FRONT. AS THE WARM 
FRONT PASSES THROUGH THE AREA ON THU...A CHC OF SHOWERS AND 
THUNDERSTORMS WILL EXIST WITH WARM AND MOIST AIR ADVECTING INTO THE 
AREA. 

A COLD FRONT WILL THEN MOVE OVER THE AREA THU NIGHT INTO EARLY FRI. 
AS THIS COLD FRONT MOVES INTO THE WARM AND MOIST AIR MASS...SHOWERS 
AND THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE THROUGH EARLY FRI. 
BEHIND THIS FRONT...COLDER AIR WILL MOVE OVER THE AREA. H85 TEMPS 
ARE PROGGED TO FALL TO BETWEEN 4 AND 8C BY NEXT SUN. THIS MIGHT BE 
JUST A LITTLE OVERDONE...BUT TEMPS SHOULD STILL FALL INTO THE 70F TO 
75F DEGREE RANGE. SOME LOCAL NORTHERN AREAS MAY NOT EVEN REACH 70F 
FOR DAYTIME HIGHS BY SUN. DRY CONDITIONS SHOULD EXIST FOR SAT AND 
SUN. THERE IS SOME INDICATION THOUGH THAT A WAVE COULD BRING A 
FRONT FAR ENOUGH NORTH TO GIVE SOUTHERN AREAS A SHOT AT SOME 
PCPN ON SAT. WILL KEEP THINGS DRY FOR NOW...BUT FUTURE SHIFTS MAY 
HAVE TO ADD PCPN IN FOR SAT.     

NJJ
 
.GRR...NONE.