455  
FXUS63 KGRR 310643  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
243 AM EDT SUN AUG 31 2025  
   
KEY MESSAGES  
 
- NEXT CHANCE FOR RAIN LATE WEDNESDAY  
 
 
   
DISCUSSION  
 
ISSUED AT 243 AM EDT SUN AUG 31 2025  
 
- NEXT CHANCE FOR RAIN LATE WEDNESDAY  
 
OVERALL PATTERN REMAINS HIGHLY AMPLIFIED AND A BIT BLOCKY OVER THE  
NEXT WEEK, MORE TYPICAL OF AUTUMN THAN LATE SUMMER. WE START OFF  
WITH A COOL SURFACE HIGH MOVING EAST WITH MODERATING TEMPERATURES  
AS UPPER RIDGING BUILDS ACROSS THE NORTHERN GREAT LAKES THROUGH  
THE FIRST HALF OF THE WEEK. THIS IS FOLLOWED BY AN UPPER LOW  
DIVING SOUTHEAST FROM CANADA AND CARVING 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 NEXT WEEKEND WITH SHORTWAVE TROUGHS AND  
VORTICITY MAXIMA ROTATING AROUND THE UPPER LOW IN BROAD CYCLONIC  
FLOW REGIME ALONG WITH STEEP MID LEVEL LAPSE RATES. UNUSUALLY COLD  
AIRMASS FOR EARLY SEPTEMBER BUILDS IN BY THE END OF NEXT WEEK WITH  
TEMPERATURES AGAIN WELL BELOW NORMAL. SOME SCATTERED FROST IS  
POSSIBLE AGAIN IN THE NORTHERN INTERIOR ZONES IF SKIES CLEAR AND  
WINDS DECOUPLE FROM THURSDAY NIGHT INTO NEXT WEEKEND.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z MONDAY/  
 
ISSUED AT 118 AM EDT SUN AUG 31 2025  
 
VFR CONDITIONS WILL CONTINUE THROUGH SUNDAY EVENING WITH LIGHT  
AND VARIABLE WINDS. JXN WILL SEE SOME SHALLOW GROUND FOG AGAIN  
TONIGHT, WITH THE FOG DISSIPATING AFTER DAYBREAK.  
 
 
   
MARINE  
 
ISSUED AT 118 AM EDT SUN AUG 31 2025  
 
HIGH PRESSURE WILL BRING LIGHT WINDS AND WAVES A FOOT OR LESS  
THROUGH MID-WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED BY  
WEDNESDAY AND THURSDAY AS LOW PRESSURE MOVES THROUGH.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...OSTUNO  
AVIATION...OSTUNO  
MARINE...OSTUNO  
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