981  
FXUS63 KGRR 010745  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
345 AM EDT TUE JUL 1 2025  
   
KEY MESSAGES  
 
- SPOTTY CHANCES FOR SHOWERS/STORMS WEDNESDAY THROUGH FRIDAY  
 
- COLD FRONT TO BRING SHOWERS/STORMS SATURDAY NIGHT INTO SUNDAY  
 
- NEAR NORMAL TEMPERATURES TODAY THEN SLOW WARMING TREND  
 
 
   
DISCUSSION  
 
ISSUED AT 345 AM EDT TUE JUL 1 2025  
 
- SPOTTY CHANCES FOR SHOWERS/STORMS WEDNESDAY THROUGH FRIDAY  
 
WE LOOK TO BE PRECIPITATION FREE TODAY AS DRIER AIR SETTLES IN ON  
WESTERLY WINDS. ON WEDNESDAY HOWEVER, DURING THE AFTERNOON AND  
EVENING, WE MAY SEE SOME ISOLATED/SCATTERED SHOWER AND  
THUNDERSTORM ACTIVITY. THE FORCING FOR THE PRECIPITATION LOOKS TO  
BE VIA 1) A LAKE BREEZE BOUNDARY PUSHING INTO INTERIOR PORTIONS  
OF THE LOWER PENINSULA AS WELL AS 2) A WEAK STATIONARY BOUNDARY  
SAGGING SOUTH OUT OF NORTHERN LOWER. PRECIPITATION COVERAGE IS NOT  
EXPECTED TO BE WIDESPREAD, BUT BOTH THE SREF AND THE HREF ARE  
SHOWING THIS POTENTIAL (TWO TRUSTED SOURCES).  
 
ON THURSDAY THE WEAK BOUNDARY IS STILL IN THE VICINITY AND THE  
SREF ONCE AGAIN IS INDICATING SOME WEAK ACTIVITY BUBBLING UP  
DURING THE HEAT OF THE DAY. AGAIN, NOT EXPECTING WIDESPREAD  
PRECIPITATION AND IN FACT MOST AREAS WILL LIKELY REMAIN DRY.  
 
FRIDAY THE MODELS BRING THE HEAT AND HUMIDITY BACK INTO THE AREA  
IN FULL SWING. AS THE MOISTURE MOVES BACK IN, IT APPEARS AS THOUGH  
WE HAVE SOME SMALL CHANCES FOR WARM FRONTAL SHOWERS AND STORMS.  
 
- COLD FRONT TO BRING SHOWERS/STORMS SATURDAY NIGHT INTO SUNDAY  
 
BETTER CHANCE FOR SHOWERS AND STORMS WILL COME SATURDAY NIGHT INTO  
SUNDAY AS A COLD FRONT MOVES INTO THE AREA FROM THE NORTH AND  
WEST. THE MODELS HAVE SLOWED THIS FRONT UP BY ABOUT 12 HOURS IN  
THE LATEST RUNS. THE FRONT IS BEING DRIVEN BY A WEAK SHORTWAVE  
TROUGH IN THE MID LEVELS WHICH IS LOSING AMPLITUDE AS IT MOVES IN.  
THAT SAID, IT IS THE BEST FORCING WE SEE IN THE 7 DAY FORECAST.  
TYPICAL MID SUMMER FORECAST THIS MORNING WHERE THERE IS VERY  
LITTLE FORCING THROUGHOUT WITH CONDITIONS BEING DOMINATED BY WEAK  
FRONTS AND THERMODYNAMICS. CHANCES FOR RAIN MID WEEK IS ONLY 20-30  
PCT. CHANCES SATURDAY NIGHT ARE 40-60 PCT.  
 
- NEAR NORMAL TEMPERATURES TODAY THEN SLOW WARMING TREND  
 
WE WILL BE LESS HUMID TODAY AND SLIGHTLY COOLER WITH HIGHS BACK  
INTO THE LOWER 80S WHICH IS NEAR NORMAL. RIDGING WILL BUILD ALOFT  
AS WE HEAD INTO THE END OF THE WEEK. 850MB TEMPERATURES WILL RISE  
AS WELL FROM AROUND +13C TODAY TO +18 TO +20C FRIDAY INTO  
SATURDAY. HIGHS WILL NUDGE UP EACH DAY AS WE MOVE FORWARD WITH  
LOWER 90S POSSIBLE ON FRIDAY AND LIKELY SATURDAY.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/  
 
ISSUED AT 206 AM EDT TUE JUL 1 2025  
 
A BAND OF POST FRONTAL MID AND HIGH CLOUDS REMAIN ABOVE THE TAF  
SITES AT 06Z. THESE CLOUDS WILL CONTINUE TO PEEL OFF TO THE EAST  
WITH THE FRONT AND ALL OF THE TAF SITES SHOULD BE CLEAR BY AROUND  
12Z. DIURNAL CUMULUS CLOUDS ARE EXPECTED TODAY WITH SCATTERED TO  
POSSIBLY BROKEN CLOUDS DEVELOPING AFTER 15Z. THESE CLOUDS WILL  
CLEAR DURING THE EVENING HOURS. BOTTOM LINE...VFR WEATHER IS  
EXPECTED THROUGHOUT THIS TAF PERIOD. WINDS TODAY WILL BE GUSTY  
FROM THE WEST-NORTHWEST (270-300) AT 12-20 KNOTS.  
 
 
   
MARINE  
 
ISSUED AT 345 AM EDT TUE JUL 1 2025  
 
HIGH RESOLUTION MODELS CONTINUE TO INDICATE WINDS REMAINING BELOW  
ADVISORY LEVELS FOR THE NEXT SEVERAL DAYS. EVEN THOUGH A COLD  
FRONT MOVED THROUGH YESTERDAY, THE WINDS IN THE WAKE OF THE FRONT  
ARE FAIRLY LIGHT. WINDS WILL PICK UP SOME TODAY, BUT REMAIN  
GENERALLY 15 KNOTS OR LESS OVER THE LAKE. SURFACE RIDGING BUILDS  
IN FOR WEDNESDAY AND THURSDAY BRINGING EVEN LIGHTER WINDS. IT IS  
NOT UNTIL WE GET TO SATURDAY WHEN A STRONGER SOUTHWEST FLOW  
DEVELOPS THAT WE COULD SEE HIGHER WINDS/LARGER WAVES. WAVES WILL  
BE 2 FEET OR LESS THROUGH FRIDAY, SO GOOD BOATING/SWIMMING  
CONDITIONS ARE ANTICIPATED.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...DUKE  
AVIATION...DUKE  
MARINE...DUKE  
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