FXUS63 KGRR 020749 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 349 AM EDT Wed Jul 2 2025 .KEY MESSAGES... - Scattered Showers/Storms Possible Today through Friday - A Better Chance for Showers/Storms Saturday night and Sunday - A Warmup into Saturday then a Slight Cooling Next Week && .DISCUSSION... Issued at 348 AM EDT Wed Jul 2 2025 - Scattered Showers/Storms Possible Today through Friday Several chances for showers and storms exist today through Friday with the first occurring this afternoon and evening. A weak surface boundary will sag south into the area this afternoon. That front combined with some convergence in the interior portion of the state will drive some scattered shower and thunderstorm activity. The eastern CWA towards Highway 127 has the best chance this afternoon and then Central and Western Lower get into the act in the late afternoon and evening. A shortwave will be working through the flow aloft so there will be some support for convection today. We are in the SPC marginal today, but any chance at severe looks pretty low. An outside chance at some localized stronger winds would be the main threat (50-60mph). Some of the activity will last until after sunset before fading. The boundary remains in the area on Thursday albeit very weak. It will be a location of some convergence however and with an unstable airmass not out of the realm that we may see some scattered showers and storms. The HREF is focusing on areas from Grand Rapids south and east through Battle Creek, Lansing and Jackson. We are in a day two Marginal as well, but again severe threat looks limited. We have gone dry for the Fourth, but would not be surprised to see some scattered showers and storms developing along a warm front. Agree with the previous discussion that the rising heights may put a lid on anything that tries to develop and actually that is what we are leaning on at this point. - A Better Chance for Showers/Storms Saturday night and Sunday A cold front pushes into the area Saturday night and progresses through on Sunday. We have 40-60 pct chances for rain in the forecast with this frontal passage. This will not be a washout by any means, but there will be some rain around. - A Warmup into Saturday then a Slight Cooling Next Week A steady warm up will continue into Friday and Saturday followed by a cooling back to normal into early next week. 850mb temperatures peak Saturday into Saturday night around +20C. This will result in highs on Saturday into the 90s. We will be well into the 80s to around 90 today through Friday, so summer like weather is certainly in the forecast for the Fourth weekend. Early next week we cool back into the lower teens C at 850mb which has our forecast highs around normals...near 80 to the lower 80s. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 151 AM EDT Wed Jul 2 2025 The main focus of the TAF period is the chance of showers this afternoon over interior portions of the state (LAN and JXN) and this evening in the west (MKG, GRR and AZO). Coverage and chances for precipitation this afternoon/evening are not high. There is a chance for a thunderstorm as well. For now though included VCSH both this afternoon and this evening as coverage will be low and chances for thunder is not high. Otherwise, VFR weather is expected through the period. Cumulus clouds will develop today, likely becoming broken at times around 5,000 feet. Winds will be southwest to west at 7-15 knots today. && .MARINE... Issued at 348 AM EDT Wed Jul 2 2025 Winds on the lighter side will continue both today and Thursday allowing for conditions on the big lake to remain sub advisory. Southerly winds begin to pick up on Friday and really increase into Saturday. The GFS has a stronger low and therefore stronger winds on Saturday. Saturday will be the day we are watching for the next possible Small Craft Advisory and Beach Hazards Statement. Main area of concern would be north of Muskegon Saturday afternoon, but at this point its somewhat marginal on the line between 2-4 feet and 3-5 feet. We have time to monitor how the winds and waves evolve. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...DUKE AVIATION...DUKE MARINE...DUKE