402 FXUS63 KGRR 281821 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 221 PM EDT Mon Sep 28 2026 .KEY MESSAGES... - More patchy areas of dense fog tonight - Rain Wednesday through Friday && .DISCUSSION... Issued at 221 PM EDT Mon Sep 28 2026 - More patchy areas of dense fog tonight High pressure remains over the Great Lakes tonight with clam winds and clear skies which means another night of good radiational cooling conditions. Similar to the past few nights, patch dense fog will form in low spots, especially near rivers and inland lakes where air temperatures cool below the still relatively warm water temperatures resulting in shallow, but dense "steam fog". - Rain Wednesday through Friday An upper low across the western CONUS will move east and pull moisture from the Eastern Pacific tropical cyclone with it, which spreads in a narrow ribbon along a nearly-east west frontal boundary by mid-week. We expect the rain to arrive by Wednesday afternoon and continue through Friday as the front moves slowly southeast, nearly parallel with the upper flow, with occasional breaks in the steady rain. Total QPF from this event is expected to be 1 to 2 inches by Friday, but we will have to watch if it overperforms from the injection of tropical moisture. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 203 PM EDT Mon Sep 28 2026 A few cumulus clouds around 4,000 feet have developed this afternoon and will dissipate around sunset. Light and variable winds overnight with clear skies are expected as high pressure moves over the region. This is another setup for patchy or shallow fog between 08 and 13 Z. VFR is then expected with south-southwest winds on Tuesday. && .MARINE... Issued at 203 PM EDT Mon Sep 28 2026 10 knot northwest winds Monday afternoon will diminish with a weak land breeze developing overnight. Waves build to 1-3 feet north of Grand Haven on Tuesday with south winds. South-southwest winds strengthen on Wednesday, which favors small craft advisory and hazardous beach conditions north of Holland. Hazardous conditions are likely to continue into Thursday && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno AVIATION...CAS MARINE...CAS

NWS GRR Office Area Forecast Discussion