665 FXUS63 KGRR 240748 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 348 AM EDT Sat Oct 24 2026 .KEY MESSAGES... - Morning Fog - Warm Weekend - Cooler Monday-Tuesday - Unsettled End of October && .DISCUSSION... Issued at 348 AM EDT Sat Oct 24 2026 - Morning Fog Overnight observations and short term guidance gives fair to good confidence in dense fog Saturday morning throughout much of Mid Michigan including along US-127 and reaching portions of US-131. There is some potential for the fog to expand west of US-131 mainly west of Kalamazoo and Grand Rapids. Similar to a couple other fog events this week, the most widespread visibilities less than a quarter mile may occur between 8 AM and 10 AM when the winds around 500 feet relax. The fog and low clouds should mix out and evaporate between 10 AM and noon, leaving the rest of the day with some cirrus. - Warm Weekend Global ensemble systems and recent short term guidance continues strong support for highs in the upper 60s to around 70 this weekend, with a flow of mild air on the back side of high pressure over the Northeast to Ohio valley. A light breeze and some increased coverage of high clouds can also be expected. - Cooler Monday-Tuesday Ensemble spread has tightened up a little on cooler temperatures Monday and Tuesday as a cold front sinks through the area. There is still some spread in the expected highs with a range between the mid 50s and mid 60s, depending the southward progress the front makes before stalling. This cool down isn`t exactly significant as it just brings temperatures closer to normal for late October. The front is also favored to come through dry. - Unsettled End of October Ensembles have a good signal for high temperatures rebounding into the 60s to near 70 on Wednesday ahead of a northern Plains low. After Wednesday, there was a significant amount of spread and lower confidence in the forecast depending on how that low would phase with the northern jet stream, and at what longitude a large scale trough within the northern stream would set up later in the week. There was a variety of solutions for late in the week with highs ranging between the 40s to near 70, however, recent cycles have increased the membership of warmer solutions. There are increasing chances for rain toward the end of the month, though confidence in that remains relatively low for now. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 158 AM EDT Sat Oct 24 2026 ASOS/AWOS reports, satellite images, and area webcams confirm LIFR fog development is underway at JXN and MOP, and is likely to spread west/north through 14 Z. Short term model guidance has a good signal for fog development affecting JXN, LAN, and BTL. GRR and AZO will be on the western edge of the fog bank and it may take a little longer for fog to develop there. There is lower confidence for fog to reach MKG. Vis and/or cigs may be at or below minimums. Similar to yesterday, about 15 knots of wind at 500 feet could delay fog development and instead result in 200 ft cigs, but winds relaxing after 11 Z may result in more widespread vis less than 1/4SM until it improves around 14 to 15 Z. After 15 Z, VFR and light south-southeast winds are expected. && .MARINE... Issued at 348 AM EDT Sat Oct 24 2026 There is a chance for an area of fog over Southwest Michigan to move over the nearshore waters this morning. Otherwise, should have good visibility with partly cloudy skies this weekend. South winds strengthening today to 10-20 knots will build 2 to 4 foot waves north of Muskegon, persisting into Sunday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Dense Fog Advisory until 10 AM EDT this morning for MIZ039-040- 045-046-051-052-057>059-065>067-072>074. MARINE...Dense Fog Advisory until 11 AM EDT this morning for LMZ848-849. && $$ DISCUSSION...CAS AVIATION...CAS MARINE...CAS

NWS GRR Office Area Forecast Discussion