textproduct: Marquette

KEY MESSAGES

- Another round of light to moderate snowfall tonight through Monday brings 1-3 inches of snow to the northern and western UP, with some locations between Ironwood and Ontonagon (as well as the rural high terrain of Baraga and Marquette Counties) reaching 4-6 inches. Banded snowfall could create highly variable road conditions.

- Dry weather Tuesday before active weather resumes for the back half of the week into the weekend. Rain will be the dominant precipitation type, which in combination of highs above freezing could cause some rivers to continue to slowly rise.

DISCUSSION

Issued at 310 PM EDT Sun Apr 5 2026

A dry airmass progressing overhead this afternoon has cleared skies over the west and will continue to usher out the lingering eastern cloud cover into this evening. Highs are expected in the mid 30s to mid 40s. This break does not last long as shortwave and surface trough analyzed to the northwest over N MN presses in. Antecedent dry air will limit precip until the evening hours. PVA and steep lapse rates support snow (possibly mixed with rain) showers this evening into tonight over the west. Best coverage this evening will be focused over the far west near WI; warm road temps could limit snow accumulations on roads initially. Lows are expected in the 20s by Monday morning.

Late tonight into Monday morning, a reinforcing mid level wave and cold front pressing south over the UP yield an uptick in snow shower activity as delta-Ts become more than sufficient for LES. Gusty winds up to 20-25 mph (up to 30 mph in the Keweenaw) accompany the convective showers (moderate snowfall rates up to 0.25-0.5 inch/hr), possibly lowering visibility to 0.5 mile at times during the morning commute. As the day progresses, delta-Ts increase but moisture, inversion heights, and steep lapse rates diminish. With the increasing sun angle in the afternoon, additional accumulations will struggle to exceed a half an inch by the evening. Opted not to hoist any Winter Weather Advisories as widespread accumulations will struggle to exceed 3 inches. That said, locally higher total amounts for tonight and Monday may reach up to 4 inches in the west between Ironwood and Ontonagon as well as up to 4-6 inches in the high terrain of Baraga and Marquette Counties. Otherwise highs on Monday will be in the mid 20s to mid 30s.

Lingering northerly LES ends from west to east Monday night into Tuesday morning as high pressure sets up over the Great Lakes. Additional snow remains below 1 inch. Cold temps are expected Monday night with the cold dry air, light winds, and subsidence. Lows in the single digits above interior west with teens elsewhere. Highs warm up on Tuesday into the 30s with plenty of sunshine.

Strong WAA and isentropic ascent touch off a round of rain and snow Wednesday morning ahead of a closed low moving in from the Canadian Prairie. This organizes a weak low pressure over the Northern Plains on Wednesday before these features track across northern Ontario Wednesday night through Thursday. After the initial precip round Wednesday morning and a brief break in the early afternoon, rain presses in from the west ahead of a cold front. Rain continues over the UP through Thursday morning. 24HR QPF values are generally expected between 0.3 to 0.6 inches by Thursday morning, but the NBM does show up to 0.75 inches with the 75th percentile. Low end amounts depicted by the 25th percentile range from a few hundreths up to 0.2 inches of QPF. The going forecast reflects mostly dry weather returning for the rest of the work week with high pressure returning save for 15-20% chances along the south and east, however some guidance does show low potential (~20% chance) for wrap around rain/snow showers into early Thursday afternoon over the north. Meanwhile, highs return to the 40s with lows in the mid 20s to low 30s save for Wednesday night when temps remain in the 30s above freezing.

Uncertainty quickly 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 period accompanied by a strong Gulf connection late weekend/early next week. The CPC captures this well with a slight/moderate risk of heavy precip early next week (moderate on April 13th and slight the 14th). 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. For now confidence is low given the murky details, but will continue to monitor this risk.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 732 PM EDT Sun Apr 5 2026

VFR conditions lower to MVFR tonight as another shortwave moves through the region. This touches off a batch of scattered snow showers; given the scattered nature of expected snow showers tonight, have gone with prob30 groups through ~12z tomorrow for periodic IFR drops in vis/cigs. There is higher confidence in MVFR ceilings beginning at IWD over the next couple of hours, followed by CMX and then SAW through the rest of the night. Stronger cold air advection ramps up tomorrow morning, bringing more persistent snow showers and MVFR/IFR conditions at all terminals, aided by lake and orographic enhancement. Diminishing winds tonight ramp up to 15-25 kts after 12z tomorrow, particularly at CMX/SAW.

MARINE

Issued at 349 PM EDT Sun Apr 5 2026

Northwest winds fall below 20 kts over the east by this evening. A disturbance tonight sends a cold front south across the lake, increasing winds lakewide to 20-30 kts for Monday morning. This drives waves of 4-8 ft. There is a 20-40% chance for gales up to 35 kts over the central third of the lake Monday morning and early afternoon. Moderate to heavy freezing spray is likely in that region. Opted to hoist a Heavy Freezing Spray Warning where confidence was highest, but held off on a Gale Warning for now. The Heavy Freezing Spray Warnings may need to be expanded/extended with the next forecast package.

Winds fall below 20 kts by early Tuesday morning with high pressure expanding over the upper Great Lakes. Winds and freezing spray also diminish because of this. The next potential for gales to 35 kts is Wednesday and Wednesday night, primarily out of the south, when a low pressure system passes north of the lake (25-45% chance for 35 kt winds over the east half of the lake). High pressure brings back quieter conditions to the lake for Friday, but an active period returns by next week.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Heavy Freezing Spray Warning from 8 AM to 8 PM EDT Monday for LSZ243-244-264.

Heavy Freezing Spray Warning from noon to 8 PM EDT Monday for LSZ245-248>250-265-266.

Lake Michigan... None.