textproduct: Marquette

KEY MESSAGES

- A system arriving late tonight will bring snow, sleet, and freezing rain through early Friday morning.

- Moderate to potentially major impacts are anticipated, including hazardous travel, power outages, and tree damage.

- A secondary system moves through the area Friday night and Saturday, bringing another round of mixed precipitation. Similar impacts are possible.

DISCUSSION

Issued at 347 PM EDT Wed Apr 1 2026

A brief clearing has been seen today across the Northern Great Lakes under the influence of a dry Hudson Bay high pressure. Area satellite imagery reveals incoming high level clouds returning as troughing emanates out of the Rockies. This quiet and dry period will be short lived as a messy winter storm ejects out of Colorado tonight and lifts through the Mississippi Valley tomorrow morning into the Great Lakes. Strong isentropic lift and midlevel warm air advection will force widespread precipitation into the UP Thursday morning, initially starting off as wet snow but quickly transitioning to sleet and freezing rain as 850-700 mb temperatures warm above freezing. There may be a slight delay in the precipitation onset given ample dry air aloft noted by area bufkit soundings, so precip may not reach the northern tier of the UP until early afternoon. Once precipitation is able to reach the surface by the late morning/early afternoon, sleet and freezing rain are expected to be the dominant type through the evening. The exception may be the far west and Keweenaw where cooler temps may allow a longer duration of wet snow. Weak elevated instability may allow a few thunderstorms to be seen (thundersleet or even thunder-freezing- rain if low level temps are cool enough) across the south-central may tomorrow evening as the surface feature draws closer to the UP. Additionally, mix transitions to all rain across the s-central and east.

Overall precip amounts between Thursday morning through Friday morning will be highly dependent on local temperature changes above and below freezing. Total snow and sleet are not expected to be great, reaching 2-4" in the west half and less than 2" elsewhere. However, freezing rain accumulations may exceed 0.1 to 0.3", highest in the high terrain of Marquette-Baraga counties, which in combination with gusty winds may exacerbate impacts. The long duration sleet and freezing rain accumulation will bring widespread moderate to high impacts in the form of hazardous travel, and potential power outages and tree damage. Winter Storm Warnings have been posted for the western 2/3rds of the UP with Winter Weather Advisories issued for Luce/Chip/Mack counties.

The next period of impactful weather will be already beginning Friday night. This system is broadly similar to the Thursday system, although there are some key differences. Similar to the first system, the second system will have a cutoff low over the Plains ejecting into the Great Lakes, impinging upon a downstream ridge. Copious Gulf moisture will be in play for the second system as well, with PWATs in the 0.75-1.00 inch range, which is +1 to +3 sigma. However, the second system looks to occlude quicker than the first system, with the occlusion process occurring to our southwest. As a result, stronger and more prolonged warm advection aloft will spread into the local area, which should result in lesser snow/sleet compared with the first event (leaving mainly a rain/freezing rain scenario). The antecedent high pressure is in more of an ideal location to feed cold/dry air into the system at low levels, over Hudson Bay with the second system as opposed to southeast Canada for the first system. It is expected that most of the freezing rain occurs Friday night, meaning that accretions won't have to fight the April sun angle. A dry slot impinging upon the area should shut off the steadier precipitation by Saturday afternoon, but also temperatures should be creeping above the freezing mark from south to north during the morning and early afternoon. Overall, expect >50% probability of greater than a tenth of an inch of ice over most of the UP, except for the Keweenaw, which should be deeper into the colder air, seeing more snow and sleet, and except for possibly portions of the UP adjacent to Lake Michigan due to the possibility of temperatures remaining above freezing with winds off the lake. There are 30-60% probabilities of greater than significant accumulations of > 0.25" flat ice over the central and western UP. Winds do not look excessively strong, but still elevated at 10-15 kt, which will increase the risk of downed branches and power outages somewhat. Impacts will be exacerbated by any lingering icing from Thursday's event, which would be most likely in the high terrain of the north-central where high temperatures Friday will be stuck near the freezing mark under mostly cloudy skies. A Winter Storm Watch will likely be necessary in upcoming forecast cycles.

Notably, the AI versions of the GEFS and EPS ensembles are further south/east with the low track, which would shift snow/sleet probs further east into the UP (and lower freezing rain probs accordingly in some areas). This is worth monitoring if the non-AI guidance trends in that direction.

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 /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 742 PM EDT Wed Apr 1 2026

VFR conditions prevail this evening under high pressure centered to the NW. Expect deteriorating conditions early Thursday morning as a low pressure system approaches from the southwest, bringing snow at first before a wintry mixture of precipitation types, including PL, FZRA, and the aforementioned SN. SAW will be the most likely to see significant FZRA and IP, with CMX more likely to see heavy wet snow. Either way, all sites are expected to hit MVFR in the morning and IFR by late morning to early afternoon, with at least 20% chances of LIFR at all sites in the afternoon, but uncertainty in the timing and duration is too high to include for this TAF. Winds will primarily out of the east for this period with some variation to the ESE and ENE.

MARINE

Issued at 347 PM EDT Wed Apr 1 2026

Breezy NE winds below 20 kts persist this afternoon and evening as high pressure meanders through James Bay. An organizing area of low pressure will lift out of the Front Range northeast into the Great Lakes tomorrow, increasing E to NE winds above 25 kts through day break and eventually becoming Gales to 35 kts by the afternoon. Gales of 35 to 45 kts will be common across the east half of the lake, especially the north shore and far eastern arm as funneling effects occur closer to Duluth. Gales diminish below 35 kts while veering due north as the low pressure sweeps through the Straits of Mackinac late Thursday - early Friday. Breezy northerlies linger through Friday before a secondary system takes a similar path late Friday through early Saturday, once again bringing NE Gales of 35-40 kts.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Storm Warning from 8 AM Thursday to 8 AM EDT Friday for MIZ001>003-084.

Winter Storm Warning from 11 AM Thursday to 8 AM EDT Friday for MIZ004-005.

Winter Storm Warning from 8 AM to 11 PM EDT Thursday for MIZ006-013-014-085.

Winter Weather Advisory from 11 AM to 11 PM EDT Thursday for MIZ007.

Winter Storm Warning from 5 AM Thursday to 1 AM CDT Friday for MIZ009>011.

Winter Storm Warning from 5 AM to 7 PM CDT Thursday for MIZ012.

Lake Superior... Gale Warning from 8 AM EDT /7 AM CDT/ Thursday to 2 AM EDT /1 AM CDT/ Friday for LSZ162-263.

Gale Warning from 1 PM Thursday to midnight EDT Thursday night for LSZ244-245.

Gale Warning from 1 PM to 8 PM EDT Thursday for LSZ246>248.

Gale Warning from 11 AM Thursday to 2 AM EDT Friday for LSZ264>267.

Lake Michigan... Gale Warning from noon to 5 PM EDT Thursday for LMZ221-248-250.