FXUS63 KGRR 250529 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 129 AM EDT Sat Oct 25 2025 .KEY MESSAGES... - Quiet Weather Next Several Days && .DISCUSSION... Issued at 258 PM EDT Fri Oct 24 2025 - Quiet Weather Next Several Days The upper low will be pulling away with lake effect rain showers ending this evening. As heights rise, a subsidence inversion forms which could trap a layer of stratus clouds this evening. Continued drying and subsidence should cause the clouds to mix out later this evening, which will allow temperatures to fall below freezing by daybreak in most places. Some steam fog is possible near inland bodies of water, but this will be shallow and mix out quickly after sunrise. A shortwave trough topping the longwave western CONUS ridge damps out across the Great Lakes on Saturday and a closed upper low over the Southern Plains moves east and forms a rex block for Sunday into next week. This is a complex pattern and models are still showing a lot of uncertainty in the specifics. Chances for measurable rains on Tuesday and Wednesday appear rather low, despite an upper low or lows retrograding into the Great Lakes from the NE CONUS by Tuesday. The higher precip chances appear to remain south of Lower Michigan, in an area of f-gen on the northern periphery of a sfc low tracking across the Ohio Valley and into the NE CONUS by late in the week. This is followed by the amplification of a longwave trough axis and strong cold advection across the Great Lakes with a chance of rain and snow showers by next weekend. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 129 AM EDT Sat Oct 25 2025 The biggest concern with regards to aviation is the potential of impactful fog through daybreak this morning. Skies have cleared out across the area, and winds have gone light and variable, allowing for a potentially good setup. Add to this lingering moisture all day that did not mix out, and it helps the cause. The highest areas are really at all sites, with maybe a little lower chance near KGRR since they cleared out earlier. KMKG has a better chance being near the more moist air along the lakeshore. After any fog dissipates by mid morning, we will see mainly mid and high clouds the rest of the period as a weak system passes by to our SW. A few diurnal clouds around 4k ft will be possible, but VFR conditions should dominate. && .MARINE... Issued at 148 PM EDT Fri Oct 24 2025 High pressure and a weaker gradient across the area will keep winds and waves below small craft advisory levels the next several days. Offshore flow then increases during the day Sunday into early next week. A Small Craft Advisory may be needed by Monday as the low- level jet increases across the lake. Given the offshore flow, any advisory would be predominantly wind driven. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno AVIATION...NJJ MARINE...Thomas