286  
FXUS63 KGRR 100813  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
413 AM EDT WED JUN 10 2026  
   
KEY MESSAGES
 
 
- AREAS OF DENSE FOG THIS MORNING  
 
- HEAT CONCERNS ACROSS SOUTHERN LOWER MICHIGAN TODAY  
 
- CHANCES FOR SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING  
 
- CHANCES FOR SEVERE THUNDERSTORMS THURSDAY EVENING/NIGHT  
 

 
   
DISCUSSION
 
 
ISSUED AT 413 AM EDT WED JUN 10 2026  
 
- AREAS OF DENSE FOG THIS MORNING  
 
WE HAVE ISSUED A DENSE FOG ADVISORY FOR THIS MORNING FOR NORTHWEST  
PORTIONS OF THE FORECAST AREA INCLUDING GRAND HAVEN, MUSKEGON,  
LUDINGTON, BALDWIN AND NEWAYGO. COOLER AIR BEING PUSHED INLAND BY  
WESTERLY WINDS IN THE LOWEST 100MB IS RESULTING IN DENSE FOG GIVEN  
THE HIGH DEW POINT AIR IN PLACE. OTHER AREAS REMAIN ABOVE ADVISORY  
LEVELS AND WE WILL MONITOR FOR ANY EXPANSION TO THE DENSE FOG  
ADVISORY. WE FEEL BY MID TO LATE MORNING THAT CONDITIONS SHOULD  
IMPROVE TO ABOVE ADVISORY CONDITIONS.  
 
- HEAT CONCERNS ACROSS SOUTHERN LOWER MICHIGAN TODAY  
 
AFTER COORDINATION WITH SURROUNDING OFFICES WE HAVE ISSUED A HEAT  
ADVISORY FOR OUR SOUTHERN ROW OF COUNTIES (THE I-94 ROW). THE HEAT  
IS A BIT BORDERLINE, BUT WE THOUGHT IT WAS CLOSE ENOUGH TO MATCH  
UP WITH NEIGHBORS TO THE SOUTH AND EAST. JACKSON COUNTY PROBABLY  
STANDS THE BEST CHANCE AT SEEING TRIPLE DIGIT MAX APPARENT  
TEMPERATURES. WITH HIGHS AROUND 90 TO THE LOW 90S AND DEW POINTS  
RISING INTO THE LOWER 70S ITS GOING TO BE HOT. THERE IS A CHANCE  
WE MAY NEED ANOTHER HEAT HEADLINE ON THURSDAY ESPECIALLY TOWARDS  
JACKSON ONCE AGAIN.  
 
- CHANCES FOR SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING  
 
ALL SOUTHWEST LOWER MICHIGAN COUNTIES ARE IN A SLIGHT RISK FOR  
SEVERE THUNDERSTORMS TODAY VIA THE STORM PREDICTION CENTER. PER  
THE LATEST HREF WE EXPECT STORMS TO APPROACH MID LAKE MICHIGAN IN  
THE 400PM HOUR AND SWEEP THROUGH THE FORECAST AREA BETWEEN ROUGHLY  
500PM AND 1000PM THIS AFTERNOON AND EVENING. THERE ARE SIGNALS IN  
THE HREF THAT DAMAGING WINDS ARE THE PRIMARY THREAT WITH 10M AGL  
ENSEMBLE MAX GUSTS EXCEEDING 60 MPH, ESPECIALLY OVER THE WESTERN  
HALF OF THE FORECAST AREA. MUCAPE VALUES WILL LIKELY EXCEED 3,000  
J/KG TODAY WHICH WILL BE COINCIDENT WITH A 850MB LLJ INCREASE TO  
30-40 KNOTS. DCAPE VALUES NEAR THE CONVECTION THIS EVENING ARE  
FORECAST TO BE IN EXCESS OF 1,000 J/KG WHICH IS A GOOD INDICATOR  
FOR DAMAGING WINDS. SOME LINGERING CONVECTION IS EXPECTED INTO THE  
OVERNIGHT, BUT A DOWNWARD TREND IN INTENSITY IS EXPECTED GIVEN THE  
STABILIZING AFFECT OF THE EVENING RAIN.  
 
- CHANCES FOR SEVERE THUNDERSTORMS THURSDAY EVENING/NIGHT  
 
THERE WILL LIKELY BE A LULL IN THE ACTIVITY THURSDAY MORNING AND  
FOR MUCH OF THE DAY FOR THAT MATTER. WHILE TODAY'S STORMS WILL BE  
LARGELY THERMODYNAMICALLY DRIVEN, THURSDAY'S STORMS WILL GET MORE  
OF A SYNOPTIC SCALE BOOST FROM A SHARP SHORTWAVE TROUGH SWEEPING  
IN AT 500MB. THE LOW LEVEL JET THURSDAY EVENING IS FORECAST BY ALL  
OF THE MODELS TO AT LEAST BE IN THE 40-50 KNOT RANGE WHICH IS  
SUBSTANTIAL FOR MID SUMMER. WINDS IN THE MID LEVELS WILL BE  
EQUALLY AS STRONG WITH A 100 KNOT JET CORE AT 500MB NOTED JUST  
UPSTREAM OVER WI/MN. SUFFICE IT TO SAY THURSDAY'S CONVECTION HAS  
SOME DYNAMICS ASSOCIATED WITH IT. MUCAPE VALUES WILL EXCEED 3,000  
J/KG AGAIN WITH MUCH STRONGER DEEP LAYER SHEAR OF AROUND 40 KNOTS.  
ALL HAZARDS ARE IN PLAY ON THURSDAY EVENING, BUT AGAIN THIS LOOKS  
TO BE ANOTHER DAMAGING WIND EVENT. MAX GUSTS IN THE HREF ARE  
INCREASING AS THE STORMS ARE APPROACHING FROM THE WEST AT THE END  
OF THE CURRENT 48HR TIME WINDOW OF THE MODEL. SPC HAS US IN AN  
ENHANCED FOR THURSDAY WHICH LOOKS WARRANTED.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
 
 
ISSUED AT 200 AM EDT WED JUN 10 2026  
 
TWO CONCERNS OVER THE NEXT 24 HOURS FOR AVIATION PURPOSES ARE  
FOG/LOW CLOUDS THIS MORNING AND CHANCES FOR THUNDERSTORMS THIS  
AFTERNOON AND EVENING.  
 
AS FOR THE FOG AND LOW CLOUDS...LOW CEILINGS HAVE SPREAD INTO WEST  
CENTRAL LOWER MICHIGAN AS OF 06Z...ESSENTIALLY FROM GRR AND BIV TO  
THE NORTH. WE EXPECT THESE LOW CLOUDS (IFR/LIFR) TO EXPAND TO THE  
EAST AND SOUTH ENCOMPASSING ALMOST ALL AREAS NEAR AND NORTH OF  
I-96 BY 10Z TO 11Z. VISIBILITIES WILL BE WORST NEAR LAKE MICHIGAN.  
THE LOW CLOUDS AND FOG SHOULD LIFT THROUGH THE COURSE OF THE  
MORNING HOURS. VFR WEATHER SHOULD PREVAIL INTO THE AFTERNOON.  
 
FOCUS IN THE AFTERNOON SHIFTS TO THUNDERSTORM POTENTIAL. WHILE  
SOME SCATTERED STORMS ARE POSSIBLY IN THE 18Z TO 21Z TIME FRAME WE  
EXPECT A SURGE OF STORMS TO MOVE IN AFTER 21Z FROM THE WEST. THESE  
STORMS WILL BE CAPABLE OF WIND GUSTS TO 35 KNOTS, WITH ISOLATED  
GUSTS TO 50 KNOTS.  
 

 
   
MARINE
 
 
ISSUED AT 413 AM EDT WED JUN 10 2026  
 
WE HAVE A MARINE DENSE FOG ADVISORY OUT THIS MORNING AND THAT IS  
WORKING OUT WELL LOOKING AT SHORELINE WEBCAMS. WE EXPECT THE FOG  
TO LIFT IN THE MID TO LATE MORNING HOURS WITH MIXING. FOCUS IS ON  
THE CHANCE OF A SMALL CRAFT ADVISORY AND BEACH HAZARDS STATEMENT  
FOR TONIGHT. AT THIS POINT THE EVENT LOOKS CONFINED TO THE NIGHT  
HOURS BETWEEN 8PM THIS EVENING AND 8AM THURSDAY. HOLDING OFF FOR  
NOW AND WILL LET THE DAY CREW LOOK AT IT. 3-5 FOOTERS LOOK  
POSSIBLE NORTH OF HOLLAND.  
 
MARINERS WILL NEED TO BE PREPARED FOR HIGH WINDS BOTH THIS  
AFTERNOON AND EVENING AND AGAIN THURSDAY EVENING ASSOCIATED WITH  
STRONG TO SEVERE THUNDERSTORMS SWEEPING ACROSS THE LAKE FROM THE  
WEST. WIND IN EXCESS OF 50 KNOTS WILL BE POSSIBLE.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 413 AM EDT WED JUN 10 2026  
 
WE HAVE HAD SOME HEAVIER RAIN FALL ACROSS THE FORECAST AREA IN THE  
PAST COUPLE OF DAYS. RADAR ESTIMATES FROM MRMS INDICATE THAT IT IS  
THE NORTHWEST CWA FROM MUSKEGON AND NEWAYGO NORTHWARD THROUGH  
HART AND SCOTTVILLE THAT HAS SEEN THE MOST RAINFALL. 1-3 INCHES OR  
RAIN IN THIS AREA HAS BEEN COMMON WITH SOME ISOLATED AREAS OF 4+  
WHICH HAS BEEN BACKED UP BY RAINFALL REPORTS. MOST OF THE  
REMAINDER OF THE AREA HAS SEEN LESS THAN AN INCH.  
 
AN ANOMALOUSLY HIGH MOISTURE CONTENT IS EXPECTED THROUGH THE  
DEPTH OF THE ATMOSPHERE OVER THE COURSE OF THE NEXT 2 DAYS WITH  
PWAT VALUES OF 1.5 TO 2.0 INCHES TODAY AND EXCEEDING 2.0 INCHES ON  
THURSDAY. SOUNDING CLIMATOLOGY FOR DETROIT SHOWS THE DAILY MAX  
VALUE FOR THIS EVENING OF 1.90 INCHES. WE WILL BE NEAR OR ABOVE  
DAILY MAX VALUES FOR THE NEXT 48 HOURS.  
 
FORECAST PRECIPITATION AMOUNTS RANGE FROM 0.75 TO 1.50 INCHES  
ACROSS ALMOST THE ENTIRE AREA VIA WPC. HREF 48 HOUR MAX VALUES  
WHICH NORMALLY EQUATES WELL TO THE HEAVIEST SWATHS SHOW THAT 1.50  
TO 3.00 INCHES IS POSSIBLE. THE HREF ONLY GOES THROUGH 00Z  
THURSDAY EVENING AT THIS POINT, SO WITH ADDITIONAL PRECIPITATION  
EXPECTED WITH THE STORMS THURSDAY EVENING/NIGHT IT IS POSSIBLE WE  
WILL SEE SOME AMOUNTS TOWARD 4.00 INCHES IN THE HEAVIEST SWATHS.  
 
GOOD NEWS IS THAT AREA RIVERS ARE WELL WITHIN BANK AND NEAR  
NORMAL VALUES. WE SHOULD BE ABLE TO ABSORB MOST OF THIS RAIN  
WITHOUT SIGNIFICANT ISSUES ON MAINSTEM RIVERS. THAT SAID, SHORT  
TERM HYDRO ISSUES ARE A CONCERN. ONCE PWAT VALUES APPROACH AND  
EXCEED 2.0 INCHES LOCALIZED FLOODING IS VERY POSSIBLE GIVEN THE  
STRONG CONVECTION WE ARE EXPECTING. LOCAL SHORT TERM FLOOD  
ADVISORIES AND WARNINGS ARE POSSIBLE OVER THE NEXT 48 HOURS DUE TO  
URBAN AND SMALL STREAMS NOT BEING ABLE TO KEEP UP WITH AND DRAIN  
THE AMOUNT OF RAIN FALLING IN SHORT DURATIONS. 1-2 INCH PER HOUR  
RAINFALL RATES ARE EXPECTED IN THE HEAVIEST CELLS.  
 

 
   
GRR WATCHES/WARNINGS/ADVISORIES
 
 
MI...DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR MIZ037-038-  
043-044-050-056.  
HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR  
MIZ071>074.  
MARINE...DENSE FOG ADVISORY UNTIL 11 AM EDT THIS MORNING FOR LMZ844>849.  
 

 
 

 
 
DISCUSSION...DUKE  
AVIATION...DUKE  
MARINE...DUKE  
HYDROLOGY...DUKE  
 
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