182  
FXUS63 KGRR 140524  
AFDGRR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND RAPIDS MI  
124 AM EDT MON JUL 14 2025  
   
KEY MESSAGES  
 
- HEAT BUILDS INTO TUESDAY  
 
- CHANCES FOR SHOWERS AND STORMS MIDWEEK  
 
- ANOTHER CHANCE FOR RAIN POTENTIALLY NEXT WEEKEND  
 
 
   
DISCUSSION  
 
ISSUED AT 221 PM EDT SUN JUL 13 2025  
 
- HEAT BUILDS INTO TUESDAY  
 
QUIET WEATHER WILL PREVAIL FROM TONIGHT INTO THE DAY ON TUESDAY AS  
HIGH PRESSURE DRIFTS THROUGH THE GREAT LAKES REGION. BUFKIT  
OVERVIEWS SHOW VERY LITTLE MOISTURE IN THE PROFILE. SOME HIGH  
CLOUDS MOVING THROUGH THE REGION TODAY WILL SHIFT SOUTHEAST  
TONIGHT AND THERE WILL BE SOME SCATTERED CUMULUS DEVELOPMENT  
TOMORROW, BUT THAT IS IT. NO PROSPECTS FOR RAIN IN THE NEXT 48  
HOURS.  
 
HEAT WILL BUILD FROM TODAY THROUGH TUESDAY WITH HIGH TEMPERATURES  
CREEPING UP FROM THE MIDDLE 80S TODAY TO AROUND 90 ON TUESDAY.  
THERE IS NOT A BIG INCREASE IN 850MB TEMPERATURES, BUT THEY ARE  
ALREADY WARM. WE ACTUALLY STAY BETWEEN +16C AND +18C THROUGH  
THURSDAY. SO, UPPER 80S TO AROUND 90 THE NEXT COUPLE OF DAYS. MID  
WEEK TEMPERATURES WILL BE AFFECTED BY CONVECTIVE CLOUDS AND  
PRECIPITATION.  
 
- CHANCES FOR SHOWERS AND STORMS MIDWEEK  
 
WE COULD SEE SOME SHOWERS AND STORM LEAK INTO THE AREA FROM THE  
WEST TUESDAY NIGHT, BUT THE BETTER BET IS WE REMAIN DRY TUESDAY  
NIGHT AS WELL. THE FOCUS IS REALLY ON A WEAK BOUNDARY WHICH WILL  
SAG THROUGH THE AREA IN THE WEDNESDAY THROUGH THURSDAY NIGHT TIME  
FRAME.  
 
THE BEST CHANCES FOR SHOWERS AND STORMS LOOK TO BE BOTH WEDNESDAY  
AFTERNOON AND EVENING AND AGAIN THURSDAY AFTERNOON AND EVENING.  
OBVIOUS REASON THERE ARE HIGHER CHANCES DURING THAT TIME IS DUE  
TO BEING AT THE DIURNAL PEAK, BUT ALSO DUE TO THE FACT THAT TWO  
SEPARATE SHORTWAVES ARE FORECAST TO BE MOVING THROUGH THE AREA AT  
THOSE TIMES. WE HAVE LIKELY CHANCES FOR SHOWERS/STORMS (60 PCT)  
DURING THE AFTERNOON/EVENING BOTH DAYS. EACH DAY HAS SOME  
SEMBLANCE OF A LOW LEVEL JET WITH WEDNESDAY HAVING STRONGER  
WINDS. EACH DAY HAS MUCAPE VALUES AROUND 2,000 J/KG POTENTIALLY.  
IN TERMS OF DEEP LAYER SHEAR IT LOOKS TO BE 20-30 KNOTS SO NOT  
OVERLY STRONG BUT BAD EITHER. POTENTIAL FOR SOME STRONGER STORMS  
BOTH DAYS FOR SURE, SO WE WILL BE WATCHING THIS TIME FRAME GOING  
FORWARD.  
 
PRECIPITABLE WATER VALUES ECLIPSE 2.00 INCHES BOTH DAYS SO LOCALLY  
HEAVY RAIN IS CERTAINLY POSSIBLE.  
 
- ANOTHER CHANCE FOR RAIN POTENTIALLY NEXT WEEKEND  
 
THERE IS MODEL DISPARITY WITH REGARD TO A SYSTEM NEXT WEEKEND. THE  
ECMWF HAS A LOW MOVING THROUGH THE GREAT LAKES SATURDAY NIGHT INTO  
SUNDAY, WHILE THE GFS IS NOW BEGINNING TO TREND SOME PRECIP IN AS  
WELL. AS WE MOVE FORWARD THE EXPECTATION IS THAT BOTH WILL LIKELY  
HAVE A SYSTEM NEXT WEEKEND. PLENTY OF TIME TO WATCH HOW THE  
PATTERN EVOLVES.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/  
 
ISSUED AT 120 AM EDT MON JUL 14 2025  
 
VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT. WINDS WILL BE WEST TO  
SOUTHWEST BLO 10 KNOTS.  
 
 
   
MARINE  
 
ISSUED AT 123 AM EDT MON JUL 14 2025  
 
WINDS AND WAVES WILL BE RELATIVELY LIGHT THROUGH TUESDAY WITH  
SLOWLY INCREASING SOUTHWEST AND SOUTH FLOW. THUNDERSTORMS ARE  
POSSIBLE FROM WEDNESDAY INTO THURSDAY AND NORTH WINDS COULD RAMP  
UP BEHIND A COLD FRONT LATER THURSDAY.  
 
 
   
GRR WATCHES/WARNINGS/ADVISORIES  
 
MI...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR MIZ037>040-  
043>046-050>052-056>059-064>067-071>074.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...DUKE  
AVIATION...OSTUNO  
MARINE...OSTUNO  
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