910  
FXUS63 KGRR 221730  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
130 PM EDT TUE APR 22 2025  
   
KEY MESSAGES  
 
- SCATTERED SHOWERS TONIGHT, CHANCE OF SHOWERS THURSDAY  
 
- INCREASED RAIN CHANCES AND WARMING LATE WEEK  
 
 
   
DISCUSSION  
 
ISSUED AT 236 AM EDT TUE APR 22 2025  
 
- SCATTERED SHOWERS TONIGHT, CHANCE OF SHOWERS THURSDAY  
 
CONDITIONS WILL BE CRY MUCH OF THE DAY AS SURFACE AND UPPER-LEVEL  
RIDGING SET UP ACROSS WEST MICHIGAN. A WARM FRONT IS FORECAST TO  
LIFT NORTH TODAY STALLING NEAR I94 TONIGHT. ISENTROPIC ASCENT WILL  
LEAD TO SCATTERED SHOWERS, MAINLY NEAR AND SOUTH OF I94. MUCAPE  
VALUES OF A FEW HUNDRED JOULES COULD SUPPORT SOME ISOLATED THUNDER  
POTENTIAL. EXACT PLACEMENT AND TIMING OF PRECIPITATION IS LIMITED  
DUE TO LACK OF DISTINCT FORCING, AND THIS IS REFLECTED IN CAM  
SOLUTIONS.  
 
AN APPROACHING SHORTWAVE MAY LEAD TO SHOWERS ACROSS THE AREA  
WEDNESDAY NIGHT/THURSDAY, WITH THE BEST CHANCE NORTH DUE TO A WEAK  
SURFACE LOW ACROSS LAKE SUPERIOR. NAM MUCAPE PROGS SHOW THAT AGAIN  
ISOLATED THUNDER IS POSSIBLE.  
 
- INCREASED RAIN CHANCES AND WARMING LATE WEEK  
 
A MID-LEVEL WAVE WILL DRIVE A SURFACE LOW THROUGH THE MID MISSISSIPPI  
VALLEY INTO THE OHIO VALLEY THURSDAY NIGHT INTO FRIDAY. THIS FORCING  
WILL LEAD TO INCREASED POTENTIAL FOR SHOWERS AND THUNDERSTORMS  
ACROSS WEST MICHIGAN. STRONG WARM AIR ADVECTION WILL LEAD TO HIGHS  
WELL INTO THE 70S ACROSS LOWER MICHIGAN. SOME PARTS OF SOUTHERN  
MICHIGAN WILL LEAD TO HIGHS MAKING A RUN TOWARDS 80 DEGREES.  
CONDITIONS THEN DRY OUT FOR THE WEEKEND AS SURFACE AND UPPER-LEVEL  
RIDGING SETS UP.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/  
 
ISSUED AT 130 PM EDT TUE APR 22 2025  
 
SHOWERS AND A FEW STORMS THAT WERE AFFECTING WISCONSIN EARLIER  
HAVE DRIED UP QUITE A BIT AS THEY HAVE MOVED TOWARD SOUTHERN LOWER  
EARLY THIS AFTERNOON. WHAT IS LEFT OF THESE IS MAINLY A CLOUD DECK  
AROUND 7-8K FT WITH MAYBE A FEW SPRINKLES REACHING THE GROUND OVER  
LAKE MICHIGAN THAT WILL MOVE OVERHEAD THIS EVENING. THE NORTHERN  
TERMINALS ALONG I-96 WILL LIKELY SEE THE CLOUDS PARTIALLY CLEAR  
OUT OVERNIGHT. THE SOUTHERN TERMINALS LOOK TO KEEP THE CLOUD COVER  
AND A FEW SPRINKLES OVERNIGHT. THE CLOUDS SHOULD THEN MOVE OUT OF  
THERE IN THE MORNING. ANOTHER BATCH OF CLOUDS AND POSSIBLE  
PRECIPITATION WILL LIKELY COME IN LATE WED, BUT IT WILL BE AFTER  
THIS FORECAST'S VALID PERIOD.  
 
 
   
MARINE  
 
ISSUED AT 236 AM EDT TUE APR 22 2025  
 
HAVE ALLOWED THE SMALL CRAFT ADVISORY TO EXPIRE AS WINDS AND WAVES  
HAVE FALLEN BELOW HAZARDOUS LEVELS. WEAK GRADIENT WINDS WILL LEAD TO  
BENIGN MARINE CONDITIONS CONTINUING OVER THE NEXT SEVERAL DAYS.  
PERIODS OF SHOWERS AND ISOLATED STORMS ARE POSSIBLE ACROSS THE  
WATERS.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...NONE.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...THOMAS  
AVIATION...NJJ  
MARINE...THOMAS  
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