textproduct: Marquette

KEY MESSAGES

- Another winter storm will bring hazardous conditions to the UP tonight through Saturday afternoon. For most of the UP, there is a 50-100% chance of seeing >0.1" of ice. There is a 50-70% chance for ice accumulations >0.25" across the interior west and central closest to the UP/WI stateline.

- Chances for significant ice accumulations are lower for areas along the Bay of Green Bay and lower elevations near Lake Superior. Difficult travel conditions are expected, along with tree damage and power outages where the heaviest icing occurs.

- Gales of 35 to 40 kts are expected across much of the central and western areas of Lake Superior tonight into Saturday.

DISCUSSION

Issued at 340 PM EDT Fri Apr 3 2026

Afternoon GOES satellite imagery and sfc analysis reveals local ridging overhead the Northern Great Lakes behind a departing trough and northeastward moving low pressure system. Cool northerly flow has touched off a few scattered snow showers this morning and afternoon, but otherwise cloudy and dry weather have been the rule. Temps have managed to climb into the low to mid 30s across the east and south-central, with a few obs hitting 40, while the entire west half remains largely below or just around freezing. Upstream, a now closed upper low spins in the northern/High Plains while surface cyclogenesis takes shape across the southern Plains. This developing surface low pressure will lift northward into the Upper Mississippi Valley tonight, kicking off another round of impactful wintry weather in the form of snow, sleet, and freezing rain.

As the closed upper low and surface reflection draw nearer to the UP tonight, strong mid-level warm air advection and northward moisture transport (near the 90-99th percentile of PWAT and IVT NAEFS climo) will overspread the UP. At the same time, strong Canadian high pressure descends southeast across James Bay into Quebec, sending low level cold air off the Canadian shield into the local area. The overrunning of warm moist air aloft and below freezing near surface temps will provide the ideal setup for another round of mixed precipitation, including the potential for significant freezing rain accumulation. Around midnight tonight, precip will lift into the southern UP. Bufkit soundings from LNL and IMT between midnight and daybreak show a prominent 850-750mb warm nose pushing ~5-6C above a ~3kft sub-freezing layer with surface temps at or a degree or two below freezing, suggesting the best freezing rain accumulation potential will be closest to the UP/WI border. Further north and west, the warm nose is not as prominent, only punching ~1-2C, suggesting that sleet and wet snow (or snow pellets) will be the predominant precip type. Models often underdo WAA, so should these midlevel temps reach a degree higher freezing rain could be the primary threat. Additionally, there is uncertainty regarding how quickly temperatures in the south-central and east warm above freezing tomorrow morning, as well as the northeast extent of the midlevel warm nose, so confidence is low regarding dominant precip type and accumulations. HREF and NBM total ice accumulation probabilities ending Saturday afternoon highlight this uncertainty. The NBM suggests high confidence (75-100% chance) of freezing rain accumulation >0.1" across much of the interior west and high terrain of the north-central, with probs drastically falling off elsewhere (<30%), however, there remains a 30-60% chance across the far eastern UP. Meanwhile, the HREF paints the same high probs across nearly the entire UP save for the lakeshores and Keweenaw. Further, the NBM gives a 50-75% chance for accumulations >0.25" along the interior UP/WI border, adding confidence in this area being the bullseye. HREF/REFS probs again add confidence in the interior west and central. In the Keweenaw, a combination of sleet/wet snow is expected where the elevated warm nose only reaches ~1C. Through Saturday morning and afternoon, a transition from freezing rain/mix to all rain is likely across the eastern half of the UP before precip ultimately tapers off. An additional inch or two of wrap around/upslope snow is possible across the west and Keweenaw Saturday evening into Sunday morning.

Overall impact ceiling is high considering the potential for ice accumulation >0.25" across the interior west and central. Current road temps above freezing suggest ice accumulation will be primarily on elevated surfaces, though a mix of freezing rain and sleet/snow will make roads slick regardless. Tree damage and power outages from ice accrual on power lines is the main concern through Saturday morning and early afternoon.

In the wake of this system, colder than normal temperatures look to prevail under broad troughing through early next week. There is a moderate chance for light accumulating snow on Monday.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 156 PM EDT Fri Apr 3 2026

Low end MVFR cigs and VFR vis persists into this evening in the wake of the low pressure system now moving into Quebec. CMX may try to briefly lift above 2kft late this afternoon/early evening, however chances of this occuring were too low (<30%) and timing was variable so mention was left out of the TAF.

Conditions deteriorate again tonight when the next system approaches the Upper Great Lakes. A wintry mix of freezing rain and sleet is expected at SAW/IWD with snow and sleet at CMX. Precip onset around 6Z for IWD/SAW and 8Z for CMX. Widespread IFR/LIFR conditions are expected by the end of the 18Z TAF period. Otherwise, northerly winds this afternoon shift east for tonight with 25-30 kt gusts at CMX tonight into Saturday.

MARINE

Issued at 340 PM EDT Fri Apr 3 2026

Another low pressure moves towards the Upper Great Lakes tonight bringing strengthening easterly winds with gales likely over the central and western part of the lake. While we may see the winds slacken a little during the day Saturday as the center of the low approaches, once the low lifts through the Straits (or Lower Michigan) Saturday evening, expect winds to back to the northwest and north, with over a 50% chance for low-end gales possible Saturday night into Sunday morning (mainly over the eastern half); some areas of freezing spray may return with the stronger winds Saturday night into Sunday morning. As high pressure ridging returns to the area on Sunday, expect the winds to dial back down to 20 knots or less by the evening hours. That being said, another shortwave low dropping down over the lake Sunday night into Monday morning may bring northerly winds of 20 to 30 knots back across the lake behind it on Monday.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Storm Warning from 2 AM to 2 PM EDT Saturday for MIZ001- 003.

Ice Storm Warning from 2 AM to 2 PM EDT Saturday for MIZ002- 004-005-084.

Ice Storm Warning from 2 AM to 11 AM EDT Saturday for MIZ006- 007-013-014-085.

Ice Storm Warning from 7 PM this evening to 1 PM CDT Saturday for MIZ009>011.

Ice Storm Warning from 10 PM this evening to 1 PM CDT Saturday for MIZ012.

Lake Superior... Gale Warning from 2 AM EDT /1 AM CDT/ to 2 PM EDT /1 PM CDT/ Saturday for LSZ162-244>248-263>266.

Lake Michigan... None.