


Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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409 FXUS63 KGRR 251731 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 131 PM EDT Wed Jun 25 2025 .KEY MESSAGES... - Multiple Rounds of Rain and Thunderstorm Chances - Hot and Humid Conditions Continue && .DISCUSSION... Issued at 323 AM EDT Wed Jun 25 2025 - Multiple Rounds of Rain and Thunderstorm Chances Our next round of rain is thanks to a 700mb shortwave within the moisture axis that moves in this morning. Current tracking of the rain moving out of NE IL has it arriving in western Muskegon/Ottawa counties around 4am. These showers will expand eastward and likely flair up along the stationary boundary currently south of I-96. Can`t rule out a rumble of thunder this morning with MUCAPE values around 500 J/kg. This afternoon most could remain dry with only isolated showers and storms expected. The best potential will be along and south of I-94 (30 to 40 percent). A few stronger storms are possible with gusty winds, but the better potential looks to be south of the area into northern Indiana which is highlighted by the current SPC outlook. Late this afternoon into tonight a warm front moves through from south to north. A weak low level jet will also shift into the area providing a source of lift along with warm air advection. This lift could set up more north of M-20, hence the higher PoPs overnight (50 to 70 percent). Scattered showers and thunderstorms will remain possible until the front moves through Friday. Thursday some strong to severe thunderstorms remain possible with the potential for strong winds. The timing of the front will determine our potential for strong to severe storms on Friday. With precipitable water values around 2 inches now until the front moves through, any shower or thunderstorm will be capable of heavy rain. As seen yesterday as storms moved through Battle Creek, rainfall rates over an inch per hour were observed. Those that see storms track over the same area over a short amount of time could see some flooding impacts, especially in known trouble spots. Saturday looks to be a break in the rain, but additional shortwave troughs bring back chances for rain and thunderstorms Sunday into Tuesday. - Hot and Humid Conditions Continue Dew points remain largely in the 60s and 70s into next week keeping the humid conditions in place. Today will be not as hot with highs in the 70s and 80s, but after today 80s to low 90s are expected each day into next week. This will result in heat index values approaching 100 Thursday through the weekend. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 125 PM EDT Wed Jun 25 2025 A stalled frontal boundary near I-94 is resulting in cooler but cloudy/showery conditions north the boundary and a bit more sunshine south of the boundary...closer to the I-94 terminals. Considerably drier air...dewpoints in the 40s/50s was noted over the northern half of Lower MI and some of that drier air will try to work south later this afternoon on northeast winds. Eventually, later tonight, the frontal boundary will move north again. We`ll see some fog develop and then burn off by mid morning. MVFR cigs/vsbys are are expected late tonight. && .MARINE... Issued at 323 AM EDT Wed Jun 25 2025 Winds and waves remain below Small Craft Advisory and Beach Hazard Statement criteria into next week. The primary concern will be the daily chances for thunderstorms. The best chances are overall during the day, but the potential exists especially tonight and Thursday night. Locally higher winds and waves are possible in any thunderstorm. Light north to northeast winds become more southerly tonight into Thursday. Winds then shift behind the front Friday to the west to northwest. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...RAH AVIATION...04 MARINE...RAH