823  
FXUS63 KGRR 290657  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
257 AM EDT MON JUN 29 2026  
   
KEY MESSAGES  
 
- NON-ZERO CHANCE FOR STORMS THIS MORNING  
 
- EXTREME HEAT STARTS TO SET IN TODAY  
 
 
   
DISCUSSION  
 
ISSUED AT 257 AM EDT MON JUN 29 2026  
 
- NON-ZERO CHANCE FOR STORMS THIS MORNING  
 
STILL THE POTENTIAL FOR A FEW LIGHTNING STRIKES FROM THE SHOWERS  
CURRENTLY OVER THE AREA. THE SHOWERS CURRENTLY OVER MICHIGAN GIVE  
OUR SOUTHERN AND EASTERN ZONES THEIR BEST SHOT FOR RAIN/THUNDER  
THIS MORNING.  
 
THE NORTHERN ZONES BEST CHANCE COMES FROM WHETHER OR NOT SHOWERS/STORMS  
CURRENTLY DEVELOPING OVER WISCONSIN MAKE A SOUTHERLY/SOUTHEASTERLY  
TURN AND MAKE IT ACROSS LAKE MICHIGAN. STILL ENOUGH INSTABILITY TO  
KEEP US IN THE MARGINAL RISK FOR SEVERE WEATHER - WITH GREATEST  
RISK FOR HAIL AND DAMAGING WINDS. MODELS HAVE ALL BACKED OFF  
SOMEWHAT ON BRINGING ANYTHING INTO THE AREA AT ALL...KEEPING  
DECAYING STORMS IN NORTHERN LOWER...SO THIS MORNING COULD ALSO BE  
A COMPLETE BUST. IT CERTAINLY A WAIT AND SEE WHAT THE NEXT FEW  
HOURS BRINGS KIND OF A MORNING. WINDOW FOR ANY STORMS TODAY SEEMS  
TO CLOSE AROUND OR SHORTLY AFTER NOON.  
 
- EXTREME HEAT STARTS TO SET IN TODAY  
 
THE WELL ADVERTISED HEAT AND HUMIDITY STARTS TO BUILD IN TODAY AND  
REMAINS THROUGH AT LEAST THE END OF THE WEEK. HIGH TEMPERATURES  
SHOULD REACH THE UPPER 80S TO LOWER 90S TODAY ACROSS WEST  
MICHIGAN...MAKING MONDAY THE COOLEST DAY OF THE WEEK. 90S TO NEAR  
100 FOR HIGHS TUESDAY THROUGH THURSDAY ARE STILL EXPECTED WITH  
HEAT INDEX VALUES OF 105+. LACK OF OVERNIGHT RELIEF FROM THE HEAT  
AND HUMIDITY STILL EXPECTED WITH LOWS IN THE 70S FOR AT LEAST THE  
NEXT 4 NIGHTS.  
 
ITS POSSIBLE WE MIGHT SEE A FEW RECORD HIGHS THIS WEEK...BUT WE  
MAY BE MORE LIKELY TO BREAK A COUPLE OF RECORD WARM LOW  
TEMPERATURES.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/  
 
ISSUED AT 128 AM EDT MON JUN 29 2026  
 
WEAK SHOWERS WITH OCCASIONAL THUNDERSTORMS OVER LOWER MICHIGAN  
WILL MOVE OFF OVER THE NEXT COUPLE OF HOURS. STILL ANTICIPATING  
A DECAYING COMPLEX OF THUNDERSTORMS TO MOVE TOWARD MKG/GRR THIS  
MORNING WITH LOW CHANCES FOR THUNDER AT BOTH TERMINALS.  
SHOWERS/STORMS ARE NOT EXPECTED TO REACH THE SOUTHERN AND EASTERN  
TERMINAL LOCATIONS. OTHERWISE...BREEZY SOUTHERLY WINDS THIS  
AFTERNOON AND EARLY EVENING WITH GUSTS OVER 30KTS POSSIBLE.  
 
 
   
MARINE  
 
ISSUED AT 257 AM EDT MON JUN 29 2026  
 
WAVES AND WINDS WILL INCREASE THROUGH THE DAY WITH HAZARDOUS  
SWIMMING AND BOATING CONDITIONS ON LAKE MICHIGAN EXPECTED THROUGH  
TUESDAY.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...BEACH HAZARDS STATEMENT THROUGH TUESDAY EVENING FOR MIZ037-043-  
050-056.  
EXTREME HEAT WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT  
THURSDAY FOR MIZ037>040-043>046-050>052-056>059-064>067-  
071>074.  
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR LMZ846>849.  
 
 
 
 
 
UPDATE...OSTUNO  
DISCUSSION...MACZKO  
AVIATION...MACZKO  
MARINE...MACZKO  
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