502 FXUS63 KGRR 091706 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 106 PM EDT Mon Mar 9 2026 .KEY MESSAGES... - Strong to severe storms possible Tuesday evening/night - Locally heavy rain possible Tuesday through Wednesday - Light wintry mix across Central Lower Michigan with system - Clipper may bring accumulating snow Thursday night/Friday && .DISCUSSION... Issued at 339 AM EDT Mon Mar 9 2026 - Strong to severe storms possible Tuesday evening/night Winds will still be breezy today, but not quite as strong as yesterday. Quiet weather for the most part is expected from today into Tuesday morning. There is a chance of some spotty light rain tonight into Tuesday associated with a developing warm front. The majority of the focus of the 7 day forecast in on the potential for severe weather Tuesday evening into Tuesday night. A plains upper trough will approach the Great Lakes Tuesday night, but will not move through until Wednesday. At the surface, low pressure will form in the plains and lift into the area Tuesday night. There is still some difference in the models in terms of low placement, but the ensemble members of both the ECMWF and the GFS seem to be honing in on Southwest Lower Michigan somewhere between SBN and GRR at 06z Wednesday. This means the warm front is likely to lift into our area. Both the GFS and NAM lift the front into our southern two rows of counties likely ending up somewhere near a line from South Haven eastward towards Mason and Jackson. Plenty of low level shear will be in place as a similar setup to last week takes shape. A strong low level jet (40-45 knots) looks to intersect the warm front over Southwest Lower Michigan Tuesday evening with backed low level flow near the warm front. NAM hodographs are showing 50 knots of deep layer shear with the bulk of that occurring in the lower 1 km. Rotating updrafts look likely given the deep layer shear so all hazards are in play...hail, wind and tornadoes. The Storm Prediction Center has increased our chance of severe weather bumping the threat from a marginal to a slight and cannot argue with that. We will be monitoring storms Tuesday evening very closely. They look to move in after 00z as the low level jet impinges on the warm front. As far as instability goes we feel this will be advected into the area on the strong winds just off the surface. - Locally heavy rain possible Tuesday through Wednesday Locally heavy rain looks more than possible as periods of showers and storms occur from Tuesday afternoon through Wednesday. We are likely looking at swaths of one to possibly two inches of rain especially from I-96 to the south. Rivers are higher now given recent rains so additional precipitation will likely push quite a few sites towards bankfull/action stage. If the rain ends up closer to an inch we will likely be able to absorb most of that without significant issues, but if it overperforms (1.5 to 2.0 inches) we would likely be looking at rivers reaching flood stage in a few spots in the Kalamazoo and Grand river basins. - Light wintry mix across Central Lower Michigan with system This system is dynamic like many systems in the early spring time frame. While storms will occur in Southern Lower Michigan, Central Michigan will be closer to the cooler air remaining in the easterly flow north of the warm front. Temperatures across Central Lower Michigan will be in the lower to middle 30s Tuesday night into Wednesday morning, so some wet snow will mix in especially near U.S. 10. As the low goes by on Wednesday colder air filters in and the rain/snow mix should chance over to all snow later on Wednesday. Accumulations are expected to be light given the marginal surface temperatures for the bulk of event. A touch of freezing rain is possible especially across Osceola and Clare Counties Wednesday morning. Given temperatures right around the freezing mark not expecting significant impacts. - Clipper may bring accumulating snow Thursday night/Friday A potent clipper system is expected to sweep from west to east through the area Thursday night into Friday. Accumulating snow is expected across Central Lower Michigan with this system. A surge of warm air ahead of the low complicates the forecast a bit, as surface temperatures try to push towards 40. Feel the system may keep the U.S. 10 corridor a bit colder and accumulations of snow are likely there. More time to look into this system as the week moves along. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 105 PM EDT Mon Mar 9 2026 Gusts of 25-30 knots from the south are expected this evening before diminishing to 5-10 knot winds overnight. Tonight, a warm front pushes north across the area with a significant increase in low-level moisture behind it. Cigs will quickly fall to IFR with a 15-25% chance of LIFR cigs, highest at MKG and AZO. Visbys are also to likely to fall to MVFR or lower, with elevated winds helping limit dense fog potential. Slow improvement of low clouds is expected over the course of Tuesday morning, with AZO/BTL/JXN still IFR by 18z. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Duke AVIATION...Thomas

NWS GRR Office Area Forecast Discussion