726  
FXUS63 KGRR 261747  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
147 PM EDT THU JUN 26 2025  
   
KEY MESSAGES  
 
- RAIN AND THUNDERSTORMS TODAY THROUGH FRIDAY  
 
- HOT AND HUMID CONDITIONS CONTINUE  
 
 
   
DISCUSSION  
 
ISSUED AT 339 AM EDT THU JUN 26 2025  
 
- RAIN AND THUNDERSTORMS TODAY THROUGH FRIDAY  
 
WARM AIR ADVECTION, MUCAPE VALUES OF 500-1000J/KG, AND A POCKET OF  
HIGHER 850MB MOISTURE IS SPARKING OFF SCATTERED SHOWERS AND  
THUNDERSTORMS THIS MORNING ALONG WITH THE LOW LEVEL JET AND THE  
REMNANT BOUNDARY FROM THE STORMS FROM WISCONSIN.  
 
WITH THE MOISTURE AND INSTABILITY IN PLACE THROUGHOUT THE DAY AS  
THE WARM FRONT SHIFTS NORTH SCATTERED SHOWERS AND THUNDERSTORMS  
ARE EXPECTED. THIS AFTERNOON THE BETTER CHANCES WILL BE FOCUSED  
EAST OF US-131 WITH THE POTENTIAL FOR SOME STRONG TO SEVERE  
STORMS. WINDS WILL BE THE PRIMARY CONCERN BUT CAN'T RULE OUT THE  
POTENTIAL FOR SOME SMALL HAIL.  
 
A LULL IS POSSIBLE TONIGHT BUT WE'LL HAVE TO MONITOR THE  
CONVECTION MOVING OUT OF WISCONSIN WITH THE SHORTWAVE TROUGH.  
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT AS IT MOVES  
THROUGH FRIDAY, AREAS SOUTH AND EAST OF GRAND RAPIDS HAVE THE BEST  
CHANCE WITH INSTABILITY BUILDING THROUGHOUT THE DAY. HREF MEAN  
SBCAPE VALUES ARE AROUND 2000 J/KG WITH AROUND 25 KNOTS OF SHEAR.  
WHILE THE SHEAR ISN'T GREAT, THERE STILL IS THE POTENTIAL FOR  
STRONGER STORMS, ESPECIALLY THE FARTHER EAST YOU GO. AGAIN WINDS  
ARE THE PRIMARY CONCERN WITH ANY STRONGER STORM.  
 
WITHIN THIS MOIST ENVIRONMENT, HEAVY RAINFALL IS LIKELY WITH ANY  
SHOWER OR THUNDERSTORM (RATES AROUND 1 INCH PER HOUR).  
THUNDERSTORMS THAT TRACK REPEATEDLY OVER THE SAME AREA COULD  
CAUSE MINOR FLOODING ESPECIALLY IN URBAN AREAS AND KNOWN TROUBLE  
SPOTS.  
 
DRY CONDITIONS RETURN FRIDAY NIGHT AND CONTINUE THROUGH MOST OF  
THE WEEKEND. THE ARRIVAL OF A LONGWAVE TROUGH AND A PARADE OF  
EMBEDDED SHORTWAVES WILL BRING THE POTENTIAL FOR SHOWERS AND STORMS  
BACK LATER SUNDAY INTO THE WORK WEEK NEXT WEEK.  
 
- HOT AND HUMID CONDITIONS CONTINUE  
 
DEW POINTS WILL CONTINUE TO BE IN THE 60S AND 70S THROUGH THE  
WEEKEND AND EVEN INTO NEXT WEEK. WITH HIGHS MAINLY IN THE 80S,  
HEAT INDICES WILL BE IN THE 90S MORE DAYS THAN NOT THROUGH THE  
WEEKEND (SATURDAY LOOKS TO REMAIN IN THE 80S). AT THIS TIME NOT  
EXPECTING VALUES TO REACH 100 OR MORE, BUT STILL TAKE CARE BY  
STAYING HYDRATED AND LIMITING TIME OUTSIDE.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/  
 
ISSUED AT 139 PM EDT THU JUN 26 2025  
 
AN UNSTABLE AIRMASS EXISTS ACROSS THE REGION THIS AFTERNOON. A  
FRONTAL BOUNDARY STRETCHES ACROSS THE CWA JUST NORTH OF I-96 WHERE  
DEWPOINTS ARE IN THE 60S; 70S SOUTH OF THERE.  
 
SHOWERS AND STORMS ARE MOVING ACROSS THE SOUTHERN TERMINALS WHERE  
STRONG WINDS/MICROBURSTS WILL BE POSSIBLE THIS AFTERNOON.  
 
MORE STORMS ARE EXPECTED TO DEVELOP OVER WISCONSIN TONIGHT AND  
THEN MOVE EAST AS THE AFOREMENTIONED FRONTAL BOUNDARY BEGINS TO  
LIFT NORTH. THIS MAY RESULT IN MORE CONVECTIVE DEVELOPMENT; WE  
INCLUDED A PROB30 MENTION FOR THAT POTENTIAL.  
 
 
   
MARINE  
 
ISSUED AT 139 PM EDT THU JUN 26 2025  
 
WAVES WILL BUILD TO AROUND 2 FEET NORTH OF HOLLAND FRIDAY  
AFTERNOON. OTHERWISE WAVES WILL GENERALLY BE LESS THAN 2 FEET FOR  
THE NEXT COUPLE OF DAYS.  
 
THUNDERSTORMS REMAIN A POSSIBILITY THIS AFTERNOON AND AGAIN FRIDAY  
AFTERNOON.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...RAH/THOMAS  
AVIATION...04  
MARINE...04  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab MI Page
The Nexlab IN Page
Main Text Page