206  
FXUS63 KGRR 280644  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
244 AM EDT SUN JUN 28 2026  
   
KEY MESSAGES
 
 
- HEAT WAVE BEGINS MONDAY, CONTINUES THROUGH AT LEAST THURSDAY  
 
- CHANCES FOR SHOWERS AND STORMS  
 
 

 
   
DISCUSSION
 
 
ISSUED AT 244 AM EDT SUN JUN 28 2026  
 
- HEAT WAVE BEGINS MONDAY, CONTINUES THROUGH AT LEAST THURSDAY  
 
HEAT AND HUMIDITY BEGIN BUILDING IN MONDAY WITH HOT AND HUMID  
CONDITIONS CONTINUING INTO THE END OF THE WEEK. HOTTEST DAYS  
CONTINUE TO BE TUESDAY, WEDNESDAY AND THURSDAY WHEN HIGHS WILL BE IN  
THE MID TO UPPER 90S AND HEAT INDEX VALUES WILL BE WELL INTO THE  
100S.  
 
MONDAY MAY NOT BE A SLAM DUNK CRITERIA HEAT WARNING DAY FOR ALL OF  
THE AREA AS LINGERING CLOUDS AND SLOW BUILDING HEAT MAY LIMIT  
TEMPERATURES ESPECIALLY THE FURTHER NORTH YOU GO. IN SPITE OF THAT  
AND MAYBE BEING A FEW DEGREES INTO ADVISORY VS WARNING GUIDANCE  
NUMBERS HERE OR THERE...THE SIGNIFICANT IMPACTS OF A PROLONGED HEAT  
AND HUMIDITY STRETCH (4 DAYS OR MORE) WARRANT THE ISSUANCE OF AN  
EXTREME HEAT WATCH FOR MONDAY THROUGH THURSDAY THAT IS LIKELY TO  
BECOME AN EXTREME HEAT WARNING SOMETIME WITHIN THE NEXT 24 HOURS.  
 
ANYTHING THAT CAN BE DONE TO PREPARE FOR THE HEAT AND HUMIDITY  
SHOULD BE COMPLETED BY TODAY AS THE HEAT BEGINS MONDAY. THIS WOULD  
INCLUDE MODIFYING SCOPE AND DURATION OF PLANNED OUTDOOR ACTIVITIES  
THIS WEEK AND TAKING EXTRA PRECAUTIONS FOR ANIMALS AND VULNERABLE  
POPULATIONS AMONG OTHER THINGS.  
 
WHILE SOME RELIEF FROM THE EXTREME HEAT MAY OCCUR AFTER  
THURSDAY...HOT AND HUMID CONDITIONS ARE EXPECTED TO PERSIST  
THROUGH AT LEAST THE 4TH OF JULY HOLIDAY WEEKEND AND POSSIBLE MUCH  
OF THE WEEK AFTER.  
 
- CHANCES FOR SHOWERS AND STORMS  
 
WITH THIS MUCH HEAT AND HUMIDITY IN PLACE IT IS NOT UNCOMMON FOR US  
TO SEE SOME AFTERNOON/EVENING ISOLATED STORMS OR MORE ORGANIZED  
ACTIVITY AS SHORTWAVES MOVE THROUGH THE GREAT LAKES REGION. BEST  
CHANCE FOR SHOWERS/STORMS AT THIS POINT STILL LOOKS TO BE THE MIDDLE  
TO THE END OF THE WEEK THOUGH MODELS CONTINUE TO SHOW LIMITED  
SUPPORT FOR SHOWERS/STORMS.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
 
 
ISSUED AT 147 AM EDT SUN JUN 28 2026  
 
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. A FEW LIGHT SHOWERS  
MAY MOVE INTO THE REGION FROM THE WEST NEAR OR AFTER 00Z...BUT  
THESE SHOULD BE PRETTY LIGHT AND ARE CURRENTLY NOT EXPECTED TO  
IMPACT VFR CONDITION. WINDS WILL BE LIGHT OUT OF THE EAST FOR THE  
FIRST SIX HOURS OR SO OF THE TAF PERIOD BEFORE SHIFTING TO BE OUT  
OF THE SOUTHEAST.  
 

 
   
MARINE
 
 
ISSUED AT 244 AM EDT SUN JUN 28 2026  
 
SUNDAY WILL FEATURE LIGHT EASTERLY TO SOUTHEASTERLY WINDS. MONDAY  
SEES THE RETURN OF THE RISK FOR HAZARDOUS WAVES THAT PROBABLY WILL  
CONTINUE THROUGH TUESDAY. SMALL CRAFT ADVISORIES AND BEACH  
HAZARDS STATEMENTS ARE LOOKING MORE LIKELY FOR BOTH MONDAY AND  
TUESDAY. THOSE LOOKING TO SEEK RELIEF FROM THE HEAT MONDAY AND  
TUESDAY SHOULD BE AWARE THAT HAZARDOUS WAVES AND CURRENTS ARE  
LIKELY TO BE ENCOUNTERED IN LAKE MICHIGAN.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...EXTREME HEAT WATCH FROM MONDAY AFTERNOON THROUGH THURSDAY  
EVENING FOR MIZ037>040-043>046-050>052-056>059-064>067-  
071>074.  
MARINE...NONE.  
 

 
 

 
 
DISCUSSION...MACZKO  
AVIATION...MACZKO  
MARINE...MACZKO  
 
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