011  
FXUS63 KGRR 261940  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
340 PM EDT SAT APR 26 2025  
   
KEY MESSAGES  
 
- FROST TONIGHT  
 
- THUNDERSTORM POTENTIAL MONDAY NIGHT AND TUESDAY  
 
- SHOWERS POSSIBLE THURSDAY AND FRIDAY  
 
 
   
DISCUSSION  
 
ISSUED AT 340 PM EDT SAT APR 26 2025  
 
- FROST TONIGHT  
 
IDEAL SET UP TONIGHT FOR COLD CONDITIONS AND SOME FROST FORMATION  
AS SKIES CLEAR AND SFC HIGH PRESSURE SETTLES DIRECTLY OVERHEAD.  
WINDS SHOULD GO LIGHT/CALM WITH LOWS DIPPING INTO THE MID 30S AND  
HAVE ISSUED OUR FIRST FROST ADVISORY OF THE NEW GROWING SEASON.  
THIS EXCLUDES NORTHERN SECTIONS WHERE THE GROWING SEASON IS MORE  
DELAYED THAN IN THE SOUTH.  
 
- THUNDERSTORM POTENTIAL MONDAY NIGHT AND TUESDAY  
 
LITTLE CHANGE FROM PREVIOUS THINKING. MOST LIKELY PERIOD FOR  
POTENTIALLY ACTIVE WEATHER LOOKS TO BE LATER MONDAY NIGHT INTO  
EARLY TUESDAY. THIS IS WHEN THE REMNANTS OF THE SEVERE WEATHER  
EVENT WHICH OCCURS TO OUR WEST ON MONDAY (SPC MODERATE RISK) WILL  
BE EDGING THIS WAY, AIDED BY A 60 KT LOW LEVEL JET. POSSIBLE  
MCS/SQUALL LINE COULD BE CROSSING THE LAKE LATER MONDAY NIGHT AND  
BRING THE THREAT OF DAMAGING WINDS TO THE LAKESHORE/WRN SECTIONS  
FOR A TIME BEFORE A WEAKENING TREND OCCURS EARLY TUESDAY. A RE-  
FIRING OF STRONG DIURNAL STORMS ALONG THE SFC COLD FRONT MAY OCCUR  
ON TUESDAY ALTHOUGH RECENT GUIDANCE TRENDS IS FOR THE FRONT TO  
CLEAR OUR AREA BEFORE THAT OCCURS. ALSO THE UPPER TROUGH IS SHOWN  
TO FLATTEN/DEAMPLIFY AS IT COMES THROUGH MI ON TUESDAY.  
 
- SHOWERS POSSIBLE THURSDAY AND FRIDAY  
 
AFTER A PERIOD OF SFC AND UPPER RIDGING ON WEDNESDAY A SHORTWAVE  
TROUGH IS SHOWN TO EJECT NORTHEAST FROM THE SRN PLAINS WHILE A NRN  
STREAM TROUGH DIGS SOUTH TOWARD THE UPPER MIDWEST. SURFACE  
BOUNDARY SOUTH OF THE STATE ACCORDINGLY LIFTS NORTHWARD THURSDAY  
AND ENSEMBLE MEAN MSLP INDICATES A SFC LOW WILL LIKELY TRACK ALONG  
THAT BOUNDARY ACROSS SRN LWR MI THURSDAY EVENING. SHOWERS AND A  
FEW TSTMS WILL BE LIKELY THURSDAY/THURSDAY NIGHT, ESPECIALLY OVER  
SRN SECTIONS, WHICH WILL BE FOLLOWED BY A CHANCE OF SHOWERS IN THE  
COOL CYCLONIC FLOW ON THE BACK SIDE OF THE SYSTEM ON FRIDAY.  
 
WEATHER FOR NEXT WEEKEND IS LOW CONFIDENCE AT THIS TIME WITH  
ENSEMBLE GUIDANCE SUGGESTING AN OMEGA/BLOCKING PATTERN DEVELOPING.  
UPPER TROUGHS ARE SHOWN OVER NEW ENGLAND/ERN GRTLKS AND OVER THE  
PACIFIC NORTHWEST WITH A LARGE UPPER RIDGE IN BETWEEN OVER THE  
CENTRAL U.S.. THE POSITION OF THESE FEATURES WILL BE KEY FOR NEXT  
WEEKEND'S WEATHER SINCE WE COULD BE COOL AND SHOWERY IF WE'RE  
PART OF THE NEW ENGLAND TROUGH OR WE COULD BE DRY/PLEASANT IF  
WE'RE MORE UNDER THE INFLUENCE OF THE UPPER RIDGE.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/  
 
ISSUED AT 143 PM EDT SAT APR 26 2025  
 
WHAT WAS MVFR CLOUD COVER HAS NOW CLIMBED ABOVE 3,000 FT AND IS  
SCATTERING OUT THIS AFTERNOON. BROKEN SKY CONDITIONS MAY PERSIST  
FOR A FEW MORE HOURS IN MID MICHIGAN INCLUDING LAN AND JXN. CLEAR  
SKIES ARE LIKELY TONIGHT WITH LIGHT WINDS.  
 
 
   
MARINE  
 
ISSUED AT 340 PM EDT SAT APR 26 2025  
 
BRISK NORTHERLY WINDS RELATED TO A SFC HIGH ADVANCING INTO THE  
REGION FROM THE NORTHWEST IS CREATING 3-6 FT WAVES AT THIS TIME.  
WINDS AND WAVES ARE EXPECTED TO QUICKLY RELAX THIS EVENING WITH  
SUNSET WITH MUCH MORE TRANQUIL CONDITIONS EXPECTED ON SUNDAY ON LK  
MI AS THE HIGH SETTLES OVERHEAD.  
 
NEXT PERIOD OF HAZARDOUS WINDS AND WAVES WILL COMMENCE ON MONDAY  
AS SOUTHERLY FLOW STRENGTHENS ON THE BACK SIDE OF THE DEPARTING  
HIGH, CONTINUING AND POSSIBLY STRENGTHENING FURTHER ON MONDAY  
NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. SOME POTENTIAL  
EXISTS FOR A LINE OF STRONG TO SVR T-STORMS TO CROSS LK MI LATER  
MONDAY NIGHT AND THIS WILL BE FOLLOWED BY A NORTHERLY WIND SHIFT  
TUESDAY BEHIND THE COLD FRONT.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...FROST ADVISORY FROM 2 AM TO 8 AM EDT SUNDAY FOR MIZ050>052-  
056>059-064>067-071>074.  
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.  
 
 
 
 
 
DISCUSSION...MEADE  
AVIATION...CAS  
MARINE...MEADE  
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