Severe Thunderstorm Warning 75, NWS Grand Rapids, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
444 PM EDT FRI JUL 23 1999

CHALLENGE FOR TODAY HAS BEEN AND WILL CONTINUE TO BE THUNDERSTORMS
WATCH 575 HAS BEEN CLEARED FOR THE GRR CWA AND REPLACED BY WATCH
576.

FIRST ROUND OF TSTMS HAS MOVED EAST AND THE NEXT ROUND IS MOVING
INTO LAKE MI. ATMOSPHERE IMMEDIATELY BEHIND THE FIRST LINE OF
CONVECTION IN THE NW PORTION OF THE CWA HAS CAPES AS LOW AS 100 WITH
CAPES OVER WRN AND SRN PARTS OF CWA RANGING FROM 2000 TO 4000 SO LIS
RANGE FROM -4 TO -8 SO AIRMASS REMAINS UNSTABLE. TSTMS ACTIVITY HAS
BEEN DIMINISHING AS IT MOVES ACROSS THE LAKE BUT EXPECT THAT AS THE
MAIN TROF FORCES THE STORMS EAST THEY WILL BEGIN TO HOLD TOGETHER AS
THEY MOVE ACROSS THE LAKE AND REGENERATE AS THEY MOVE OVER THE
WARMER LAND.

INTERESTING FEATURE ON RADAR THIS AFTERNOON IS AN OUTFLOW BOUNDARY
FROM SOUTH CENTRAL NEWAYGO COUNTY ACROSS KENT TO SE EATON COUNTY.  A
SMALL A WEAK STORM FIRED ON THE BOUNDARY EARLIER BUT IT HAS YET TO
PROVIDE A FOCUS... EXPECT THIS TO CHANGE LATER THIS EVENING AS THE
STORMS FROM WISCONSIN MOVE INTO OUR AREA.

REMAINDER OF FORECAST...HOT AND DUSTY AS WE REALLY HAVE NO REAL
CHANGE IN AIRMASS. DEWPOINTS GO FROM THE 70S TO THE 60S SO STILL
UNCOMFORTABLE BUT HEAT INDICES WELL BELOW THE VALUES THEY REACHED
TODAY EVEN THOUGH TEMPS WILL BE WARMER.  ZONAL FLOW WITH 5OO MB
RIDGE BUILDING BACK INTO THE GREAT LAKES EARLY NEXT WEEK.
.GRR...NONE.
MWH