250  
FXUS63 KGRR 301142  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
742 AM EDT SAT AUG 30 2025  
   
KEY MESSAGES
 
 
- NEXT CHANCE FOR RAIN LATE WEDNESDAY  
 

 
   
DISCUSSION
 
 
ISSUED AT 327 AM EDT SAT AUG 30 2025  
 
- NEXT CHANCE FOR RAIN LATE WEDNESDAY  
 
SURFACE HIGH DOMINATES THE GREAT LAKES THROUGH THE FIRST HALF OF  
NEXT WEEK WITH UPPER HEIGHT RISES BRINGING SLOWLY MODERATING  
TEMPERATURES. THE WARMING WILL BE BRIEF HOWEVER AS ANOTHER UPPER  
LOW DIVES SOUTHEAST FROM CANADA AND CARVES OUT A LONGWAVE TROUGH  
ACROSS THE CENTRAL AND EASTERN CONUS BY LATE IN THE WEEK. MOISTURE  
STREAMING UP FROM THE SOUTH WILL CONVERGE WITH THE TROUGH AXIS  
AND A SURFACE LOW TRAILING A COLD FRONT BY WEDNESDAY NIGHT WITH  
SHOWERS AND A FEW THUNDERSTORMS POSSIBLE.  
 
DIURNALLY DRIVEN SHOWERS WITH SOME LAKE ENHANCEMENT ARE POSSIBLE  
ON THURSDAY THROUGH THE END OF THE WEEK WITH SHORTWAVE TROUGHS AND  
VORTICITY MAXIMA ROTATING AROUND THE UPPER LOW IN BROAD CYCLONIC  
FLOW REGIME ALONG WITH STEEP MID LEVEL LAPSE RATES.  
 

 
   
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
 
 
ISSUED AT 741 AM EDT SAT AUG 30 2025  
 
VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT WITH LIGHT AND  
VARIABLE WINDS.  
 

 
   
MARINE
 
 
ISSUED AT 124 AM EDT SAT AUG 30 2025  
 
RELATIVELY CALM CONDITIONS EXPECTED FOR THE NEARSHORE WATERS  
THROUGH EARLY NEXT WEEK AS HIGH PRESSURE DOMINATES THE GREAT LAKES  
REGION. WATER AND AIR TEMPERATURES WILL REMAIN RATHER COOL FOR  
SWIMMING.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ039-040.  
MARINE...NONE.  
 

 
 

 
 
DISCUSSION...OSTUNO  
AVIATION...OSTUNO  
MARINE...OSTUNO  
 
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