920 FXUS63 KGRR 221700 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI Issued by National Weather Service Detroit/Pontiac MI 100 PM EDT Thu Oct 22 2026 .KEY MESSAGES... - Dry and Mild with Morning Fog - Chances for Rain Return Next Week && .DISCUSSION... Issued at 330 AM EDT Thu Oct 22 2026 - Dry and Mild with Morning Fog Ensembles continue to lend high confidence in tranquil and warmer than normal conditions through the weekend. A sharpening upper level ridge over the central CONUS will reinforce a sprawling high pressure anticyclone in the low levels across the Great Lakes, migrating toward the Northeast. There is increasing ensemble spread and thus lower confidence in high temperatures starting on Monday and extending through the week, and highs may plausibly be anywhere in the 50s or 60s. This will depend on the magnitude of northern stream troughing that occurs over south-central Canada and the Great Lakes, and the southward extent which cooler air may reach. Ensemble members also diverge into clusters regarding the the potential for a recovery of warmer air around the middle of the week. So, next week is relatively unsettled. Areas of fog are likely to develop each of the next few mornings, as they have the past couple mornings. The REFS handled the general location of the Wednesday morning fog threat in Mid Michigan fairly well. For this Thursday morning it has been suggesting areas of overnight fog mainly between Muskegon and Ludington, which has so far been the case, and patchy fog may develop elsewhere around daybreak. Tonight into Friday morning, with the surface high centered north of Lake Huron, a flow of relatively moist air off Lake Huron will spread into Mid Michigan during the late evening, setting up fog potential first near US-127 and spreading west toward US-131 areas around daybreak Friday. - Chances for Rain Return Next Week The chance for precipitation is basically nil until about Tuesday or Wednesday next week, and even so is far from settled. Any individual model solutions producing heavy rain or strong winds the middle of next week are outliers. The potential for a significant autumn storm system -- even with the unsettled evolution of the northern stream -- is remarkably low for this point in the season. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 100 PM EDT Thu Oct 22 2026 Clear and quiet through the rest of the day. Expecting fog to develop across the middle of the Lower Peninsula in the predawn hours. Given the position of the surface high overnight, there will be an increased chance of LIFR fog - with tempos down to a 1/4SM and JXN/LAN/GRR around sunrise and a couple hours thereafter. Fog should lift and thin during the mid-morning hours. && .MARINE... Issued at 330 AM EDT Thu Oct 22 2026 Light winds and a rather calm lake can be expected today. Southeast winds on Friday will be a touch stronger but only about 10 knots. South winds on Saturday 15 to 20 knots may build waves to 2 to 4 feet north of Whitehall. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...CAS AVIATION...Mann MARINE...CAS

NWS GRR Office Area Forecast Discussion