textproduct: Marquette

KEY MESSAGES

- Northerly lake effect snow showers continue overnight into Tuesday, diminishing from west to east with dry weather returning by Tuesday afternoon. Additional snow amounts mainly between 1 to 2 inches.

- Banded snowfall may create highly variable road conditions and rapid visibility drops, especially when paired with gusty winds.

- Active weather resumes this weekend. Rain will be the dominant precipitation type, which in combination with a prolonged period of above freezing temperatures could result in river rises.

DISCUSSION

Issued at 318 PM EDT Mon Apr 6 2026

Afternoon GOES water vapor imagery places the Great Lakes underneath a broad trough with an upstream ridge over the Canadian Prairie. Beneath it a high pressure moves in from the northwest and a weak surface trough and cold front continue to depart toward the Lower Great Lakes. Upper Michigan now in the wake of the cold front is under a cold northerly flow set up with 850mb temps lowering to -18C by this evening, supportive of LES noted on the radar mosaic. Some isolated showers away from the typical lake effect snowbelts are possible yet through early this evening thanks to the embedded shortwave and lingering higher lapse rates (15-25% chance). Also courtesy of this unstable airmass progressing through is gusty northwest winds up to 35 mph, highest over the east. Lingering showers, especially paired with gusty winds, could lower visibility down to half mile at times. High pressure builds in over the Great Lakes through Tuesday, ushering in drier air and ending LES from west to east through Tuesday morning. Also inversion heights are only 4-7 kft, higher over the east, with unimpressive moisture profiles the remainder of the lake effect period. Additional accumulations will be on the light side of 1-2 inches, however warm pavement temps may limit how much, if any, accumulates on roadways through this evening. Otherwise temps lower into the single digits above by Tuesday morning interior west courtesy of high pressure, a drier and seasonably cold airmass, and light winds under clearing skies. Lows in the teens are expected elsewhere. Tuesday otherwise remains quiet with plenty of sunshine and highs in the 30s.

High pressure shifts east to New England Tuesday night and a LLJ strengthens over the Upper Midwest. Meanwhile a closed low upstream dipping into the Northern Plains develops a surface low just north of ND. This begins WAA from southerly flow and increases gusts up to 20-25 mph in favorable south downslope areas. Temps will be warmer than tonight, only dipping into the 20s for most.

Strong WAA and isentropic ascent touch off a round of snow possible mixed with freezing rain/rain early Wednesday morning followed by just rain/freezing rain late morning and possibly a brief dry period early afternoon. The surface and closed low track over northern Ontario Wednesday night through Thursday, sending a cold front from west to east across the area bringing additional rain showers with it Wednesday evening into Thursday morning. 24HR QPF values are generally expected between 0.2 to 0.4 inches by Thursday morning. The going forecast reflects mostly dry weather returning for the rest of the work week with high pressure returning save for 15-30% PoPs clipping the south half early Friday morning. Meanwhile, highs return to the 40s to low 50s with lows in the mid 20s to low 30s save for Wednesday night when temps remain in the 30s.

Uncertainty grows this weekend into early next week as models struggle to resolve how the split flow over the west coast breaks down the zonal flow over the Great Lakes. The troughing, which is anticipated to return to the Great Lakes, sets up an active rainy period accompanied by a strong Gulf connection. Temps warming up into the 50s to 60s during the day, remaining above freezing overnight, potential for high QPF forecast, and a above normal snowpack still present heightens attention toward snowmelt and resulting river rises/flooding risk. For now confidence remains low given the murky details, but will continue to monitor this risk.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 721 PM EDT Mon Apr 6 2026

Snow showers are wrapping up this evening, with ceilings lifting to VFR and lake clouds scattering out. VFR prevails through the remainder of the forecast period. N-NW winds gusting to 25-30kt fall back over the next few hours, becoming light and variable tonight into early Tue.

MARINE

Issued at 340 PM EDT Mon Apr 6 2026

North-northwest winds lakewide between 20-30 kts with low end gales to 35 kts lingering over the eastern waters gradually diminish from west to east through tonight as high pressure builds in. Winds return 20 kts or less by Tuesday morning. Heavy Freezing spray ends this evening/early tonight as winds and waves diminish. Maintained headlines as is from this morning's updates.

Relatively quiet conditions hold until early Wednesday morning when south to southeast winds increase, bringing 25-50% chances for gales to at least 35 kts over the east half of the lake. As a low pressure system tracks to the north, a cold front moves across the lake into Thursday. This shifts winds westerly between 20-30 kts, but chances for gales are much lower (15-25%). Winds once again fall below 20 kts Thursday night and remain low through the rest of the work week. Active weather resumes this weekend, but uncertainty in the details remains high.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Heavy Freezing Spray Warning until 8 PM EDT this evening for LSZ243>245-248>250-264>266.

Heavy Freezing Spray Warning until 2 AM EDT Tuesday for LSZ251- 267.

Lake Michigan... Gale Warning until 8 PM EDT this evening for LMZ221-248-250.