926 FXUS63 KGRR 061116 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 716 AM EDT Mon Sep 6 2021 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 328 AM EDT Mon Sep 6 2021 - Upper troughing with severe weather possible Tuesday && .DISCUSSION...(Today through next Sunday) Issued at 328 AM EDT Mon Sep 6 2021 After a fair weather Labor Day, we look to the risk of severe weather on Tuesday as an upper trough amplifies across the central Great Lakes with wind profiles showing 40 knots of deep layer shear. Strong unidirectional shear suggests storm type will favor linear, bowing segments. Any deep convection will be capable of wind damage given 50 knots progged to be near 5 kft AGL. A dry adiabatic subcloud layer will enhance downburst potential. Timing looks to be from mid-afternoon across the northwest forecast area to mid-evening by the time the storms clear the southeast sections near Jackson County. Synoptic wind gusts in the cold advection behind the storms could also gust over 40 mph. The storms could also build deep enough to produce large hail with forecast soundings showing CAPE through the minus 10C to minus 30C zone. The storms will be moving quickly so even if heavy rain rates materialize, flooding should be mitigated by storm speed. Fair and cool weather follows for Wednesday through Friday with overnight lows in the 40s in most places by Thursday morning and even some 30s are possible in the cold spots. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) Issued at 711 AM EDT Mon Sep 6 2021 Some patchy, shallow ground fog early this morning at AZO will mix out quickly with VFR prevailing across all of Lower Michigan through tonight. West to northwest winds will be around 10 knots today and then diminish to less than 10 knots this evening. && .MARINE... Issued at 300 AM EDT Mon Sep 6 2021 Winds and waves will decrease this morning and we expect to let the Small Craft and Beach Hazards Statement expire at 8 am. Winds and waves will increase again on Tuesday and severe thunderstorms are possible in the afternoon. Conditions will remain hazardous through Wednesday as strong winds and high waves continue. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement until 8 AM EDT this morning for MIZ037- 043-050-056-064-071. LM...Small Craft Advisory until 8 AM EDT this morning for LMZ844>849. && $$ SYNOPSIS...Ostuno DISCUSSION...Ostuno AVIATION...Ostuno MARINE...Ostuno