880  
FXUS63 KGRR 111915  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
315 PM EDT TUE AUG 11 2026  
   
KEY MESSAGES
 
 
- SHOWERS AND STORMS MOVING TO THE SOUTH; PATCHY FOG OVERNIGHT  
 
- CHANCES FOR STORMS TOMORROW  
 
- NEXT CHANCE FOR SHOWERS/STORMS OVER THE WEEKEND  
 

 
   
DISCUSSION
 
 
ISSUED AT 303 PM EDT TUE AUG 11 2026  
 
- SHOWERS AND STORMS MOVING TO THE SOUTH; PATCHY FOG OVERNIGHT  
 
THE QUASISTATIONARY BOUNDARY CONTINUES TO SAG SOUTHWARD AND WILL  
PUSH ANY SHOWERS/STORMS IN THAT DIRECTION. THERE HAS BEEN SOME  
LIGHT RAIN ALONG THE I 94 CORRIDOR, WITH THE ANVIL FROM THE  
THUNDERSTORMS THROUGH SOUTHERN MICHIGAN BRINGING SOME RUMBLES OF  
THUNDER AND VICINITY LIGHTING TO THAT REGION. HOWEVER, THE STORMS  
THEMSELVES CONTINUE THEIR SOUTHWARD TREK TOWARD THE SOUTHEAST.  
LIGHT WINDS, A MOIST SURFACE LAYER AND RECENT RAINFALL IS A  
RECIPE FOR PATCHY FOG OVERNIGHT INTO WEDNESDAY MORNING. EXPECT  
THIS FOG TO BE DENSE AT TIMES AND WILL LINGER THROUGH THE MORNING  
COMMUTE.  
 
- CHANCES FOR STORMS TOMORROW  
 
THOUGH THERE IS A SIGNAL FOR DECENT CAPE VALUES FROM THE SFC  
MOISTURE AND DAYTIME TEMPERATURES INTO THE 80S, THE ATMOSPHERE IS  
FAIRLY STABLE, ESPECIALLY SINCE THE BOUNDARY REMAINS TO THE SOUTH.  
LATEST HREF DOES SHOW THE POTENTIAL FOR A WEAK MID LEVEL TROUGH  
AND SOME SHEAR THROUGH NORTHERN LOWER MICHIGAN IN THE AFTERNOON.  
THAT COULD TAKE ADVANTAGE OF THE 1K J/KG OF CAPE WEDNESDAY  
AFTERNOON. FOR THOSE REASONS, SPC HAS A RIBBON OF MARGINAL RISK OF  
SEVERE STORMS THROUGH THE CENTRAL AND NORTHERN HALF OF LOWER MI  
TOMORROW AFTERNOON AND EVENING.  
 
- NEXT CHANCE FOR SHOWERS/STORMS OVER THE WEEKEND  
 
THE LARGE UPPER LEVEL LOW OVER NORTHERN CANADA CONTINUES TO SEND  
WAVES THROUGH MICHIGAN THROUGH TH WEEK. HOWEVER, WE REMAIN FAIRLY  
STABLE THROUGH THE LATTER HALF OF THE WEEK WITH TEMPERATURES AT,  
TO BELOW NORMAL INTO THE WEEKEND.  
A LARGE UPPER LEVEL LOW WILL MOVE INTO THE THE GREAT LAKES  
REGION THROUGH THE AREA MID TO LATE WEEKEND WITH CHANCE FOR RAIN  
INTO SUNDAY.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
 
 
ISSUED AT 201 PM EDT TUE AUG 11 2026  
 
WHILE STRATIFORM RAIN OVERSPREADS THE REGION THE ANVIL FROM THE  
STORMS OVER SOUTHERN MI IS SPREADING OVER THE SOUTHERN TAF SITES.  
THIS HAS ALLOWED FOR VCTS AT AZO AND CAN'T RULE IT OUT FOR BTL.  
NOT EXPECTING TSRA AS THE STORMS SHOULD MOVE SOUTHWARD AS THE  
BOUNDARY PUSHES IN THAT DIRECTION. THAT SAID, CAN'T RULE OUT VCTS  
FOR THE NEXT FEW HOURS AT AZO AND BTL. LIGHT SHOWERS WILL  
OVERSPREAD THE REGION AND THERE REMAINS A CHANCE FOR TSRA AT THE  
SOUTHERN TAF SITES THROUGH 00Z.  
ANOTHER ROUND OF IFR CIGS AND VSBYS IN FOG/MIST AND LOW STRATOCU  
WILL BE POSSIBLE OVERNIGHT INTO WEDNESDAY MORNING. EXPECT SHOWERS  
REDUCING CIGS AND VSBYS FROM AROUND 05Z UNTIL 13Z. CONDITIONS  
SHOULD IMPROVE FROM 13Z TO 15Z WEDNESDAY.  
 

 
   
MARINE
 
 
ISSUED AT 312 PM EDT TUE AUG 11 2026  
 
SHOWERS AND STORMS WILL MOVE TO THE SOUTH THIS AFTERNOON AND  
EVENING. A TYPICAL MID SUMMER WEATHER PATTERN WILL CONTINUE THE  
NEXT FEW DAYS. LIGHT WINDS WILL CONTINUE. EXPECT SUNSHINE AND  
SOME OF OUR WARMEST WATER TEMPERATURES. WINDS AND WAVES WILL  
REMAIN FAIRLY LIGHT THROUGH TOMORROW.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
MARINE...NONE.  
 

 
 

 
 
DISCUSSION...CERU  
AVIATION...CERU  
MARINE...CERU  
 
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