477  
FXUS63 KGRR 161723  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
123 PM EDT TUE SEP 16 2025  
   
KEY MESSAGES  
 
- DRY AND WARM THROUGH FRIDAY  
 
- SHOWERS POSSIBLE THIS WEEKEND INTO NEXT WEEK  
 
 
   
DISCUSSION  
 
ISSUED AT 237 AM EDT TUE SEP 16 2025  
 
- DRY AND WARM THROUGH FRIDAY  
 
WITH HIGH PRESSURE IN PLACE AND LIGHT WINDS WE WILL HAVE THE  
POTENTIAL FOR FOG THE NEXT FEW NIGHTS AND EARLY MORNINGS. WE'RE  
ALREADY SEEING SOME VISIBILITY DROPS TOWARD ALMA AND LOWER  
CEILINGS IN MOUNT PLEASANT. THIS IS SEEN ON THE NIGHTTIME  
MICROPHYSICS SATELLITE IMAGERY EXPANDING FROM SAGINAW BAY. IT IS  
IN THIS AREA WE ARE EXPECTING THE LOWEST VISIBILITIES TO BE  
PRESENT WITH SOME LOCALLY DENSE FOG POSSIBLE. REDUCED VISIBILITIES  
COULD EXPAND ACROSS THE US-127 CORRIDOR WITH ANY FOG BURNING OFF  
WITHIN A FEW HOURS OF SUNRISE. SIMILAR CONDITIONS ARE EXPECTED  
TUESDAY NIGHT INTO WEDNESDAY MORNING AND COULD EXPAND FARTHER  
WEST. MAKE SURE TO SLOW DOWN, GIVE YOURSELF EXTRA TIME, AND USE  
YOUR LOW-BEAM HEADLIGHTS IN FOG.  
 
LIGHT EASTERLY WINDS AND WARM TEMPERATURES WITH HIGHS IN THE 80S  
CONTINUE THROUGH THE WEEK. A LAKE BREEZE IS LIKELY EACH DAY  
BRINGING SOME COOLER TEMPERATURES ALONG THE LAKESHORE DURING THE  
AFTERNOON. A FRONT THURSDAY NIGHT INTO FRIDAY WILL BRING SLIGHTLY  
LOWER TEMPERATURES FOR FRIDAY WITH HIGHS IN THE MID 70S TO MID  
80S. THE 10 TO 20 PERCENT POPS ALONG THIS FRONT HAVE DECREASED  
WITH THE LATEST TRENDS. THIS IS LIKELY DUE TO THE DRY AIR IN  
PLACE, BUT SOME INCREASED CLOUD COVER REMAINS POSSIBLE.  
 
- SHOWERS POSSIBLE THIS WEEKEND INTO NEXT WEEK  
 
AS THE UPPER LEVEL RIDGE WEAKENS, A WEAK SHORTWAVE TROUGH  
APPROACHES FOR THE WEEKEND. THIS MAY BE ENOUGH FOR SOME SHOWERS TO  
DEVELOP SATURDAY AND CONTINUE INTO SUNDAY. ENSEMBLES PICK UP ON  
THIS MORE HEADING INTO SUNDAY NIGHT AND THEN ARE IN EVEN MORE  
AGREEMENT HEADING INTO MONDAY AND TUESDAY. THE HIGHER CONFIDENCE  
TOWARD THE BEGINNING OF NEXT WEEK IS DUE TO A STRONGER/DEEPER  
TROUGH BRINGING WITH IT BETTER MOISTURE. AMOUNTS OVERALL LOOK  
LIGHT IN THE ENSEMBLES WITH ONLY A 5 PERCENT PROBABILITY OF AN  
INCH OR MORE DURING ANY 24 HOUR PERIOD.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/  
 
ISSUED AT 122 PM EDT TUE SEP 16 2025  
 
THIS AFTERNOON THROUGH EARLY WEDNESDAY MORNING WILL FEATURE LITTLE  
IN THE WAY OF AVIATION CONCERNS WITH JUST A FEW HIGH CLOUDS AND  
WINDS OF 5 KNOTS OR LESS. GUIDANCE CONTINUES TO SUGGEST THAT FOG  
WILL DEVELOP ASSOCIATED WITH EASTERLY FLOW OFF OF ERIE AND HURON  
AFTER 09-10Z. LOW STRATUS MAY ALSO DEVELOP, PARTICULARLY AT  
LAN/JXN. CONDITIONS WILL BE WORST AT LAN AND JXN WHERE LIFR  
CONDITIONS ARE POSSIBLE, WITH IFR FOR AZO/BTL AND POSSIBLY GRR  
BEING FARTHER FROM THE MOISTURE SOURCE. FOG WILL BURN OFF AN HOUR  
OR TWO AFTER SUNRISE RETURNING CONDITIONS TO VFR.  
 
 
   
MARINE  
 
ISSUED AT 237 AM EDT TUE SEP 16 2025  
 
FAIR CONDITIONS CONTINUE THROUGH THE WEEK WITH A CHANCE (20 TO 30  
PERCENT) FOR SHOWERS OVER THE WEEKEND. WINDS WILL BE EASTERLY  
INITIALLY DURING THE DAY BEFORE THE LAKE BREEZE DEVELOPS AND MOVES  
MORE ONSHORE DURING THE AFTERNOON TODAY AND WEDNESDAY. WAVES OF A  
FOOT OR LESS ARE EXPECTED THROUGH MOST OF THE FORECAST.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...RAH  
AVIATION...THOMAS  
MARINE...RAH  
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