textproduct: Marquette

KEY MESSAGES

- Winter Storm Warnings and Watches are in effect for much of the UP as a deepening low pressure tracks across the UP tonight into Wednesday, with an eventual transition to lake effect snowfall. Chances of 12 inches or more of snow are around 100% percent across the north-northwest wind snow belts of the western UP by Thanksgiving, with some spots potentially receiving 2 to 3+ feet.

- Wind gusts of 25-35 mph are expected Wednesday, with some gusts to 50 mph or more possible over the Keweenaw, the higher elevations of Baraga County, and along the lakeshore of Marquette and Alger counties. The combination of wind and moderate to heavy snowfall could make Thanksgiving holiday travel very difficult to downright impossible at times. The high winds could create some power outages.

- Given the high snowfall rates and strong winds, blizzard conditions are possible across Gogebic, Ontonagon, northern Houghton, and Keweenaw counties late tonight through Wednesday (30 to 50% chance).

- Gales up to 45 kt are expected (70-90%) on Lake Superior this evening through Thanksgiving, with Storm-Force gust to 50 kt possible (40 to 60% chance). Wave heights of 12-18 ft are expected, with some spots near Stannard Rock and between Marquette and Grand Marais seeing up to 18-21 ft waves.

- Some minor lakeshore flooding and beach erosion is possible along the Lake Superior shoreline late tonight through Thanksgiving given the strong winds and waves coming off of the lake.

DISCUSSION

Issued at 400 AM EST Tue Nov 25 2025

As two shortwave lows, one bringing snowfall to the Northern Plains this morning and another lifting north from the Southern Plains and Mid-Mississippi Valley, phase with one another today over the Upper Mississippi Valley, expect light rainfall (which has already begun over the southern half of the U.P.) to spread into the rest of Upper Michigan today. With overcast skies and rainfall overhead, expect highs today to range from the upper 30s in the west to the mid 40s in the south central and east.

The winter weather action generally begins this evening over the western U.P. as the now-phased-and-deepening low allows moisture- rich Gulf air to wrap around and over the just-sub-freezing air across the western third of the Upper Peninsula. This may occur earlier today too, with some of the CAMs guidance (such as the NAMNest) bringing moderate to borderline heavy snowfall across the west as soon as early this afternoon. However, with most guidance keeping temperatures just right above freezing throughout the daylight hours today across the area, confidence is lacking on whether the developing TROWAL of the low will be able to bring high enough snowfall rates to overcome the above-freezing air at the sfc via dynamic cooling of the atmospheric profile (thinking around 30% or less on accumulating snow until the evening hours). However, snowfall accumulation chances rapidly increase over the western U.P. once the sun sets and colder air starts to slowly make its way eastward across Upper MI tonight. As the low continues to deepen as it lifts northeast towards Lake Superior tonight, the TROWAL of the low will bring snowfall rates of 1+ inch/hour across much of the western U.P. (50+% chance for every hour tonight through Wednesday according to the 00z HREF; 90+% chance according to the NBM). With colder air coming in from the north and the pressure gradient around the low tightening with time, an upslope and lake enhancement component will assist in keeping the snowfall rates high tonight into Wednesday across the west and Keweenaw. In addition, due to the low deepening and the pressure gradient around it tightening, expect the winds over the west to drastically increase, with the incoming cold air advection helping to bring the much higher winds aloft to the sfc, even during the overnight hours. Gusts as high as 50 (or more) mph could be realized over the Keweenaw, higher elevations of Baraga County, and even near the lakeshores of Marquette and Alger counties later Wednesday. Meanwhile, frequent gusts of 35 mph or greater are expected for several hours across the far west. Thus, we very well might see Blizzard conditions across Gogebic, Ontonagon, northern Houghton, and Keweenaw counties late tonight through Wednesday, as all the criteria for a Blizzard Warning seems to be met (the HREF shows a 30 to 50% chance for several hours tonight through Wednesday). However, decided to hold off on issuing a Blizzard Warning for these counties for now given that the onset of the heavy snowfall is about 18 hours away; will let the dayshift decide if a Blizzard Warning is warranted for these areas.

As the low lifts into Lake Superior Wednesday and away towards northern Quebec later in the day, expect the transition from rain to snowfall to continue west to east. As the TROWAL progresses eastward with time, the heavier snowfall looks to be seen over Marquette County during the morning hours (after the sunrise) and the eastern U.P. by the afternoon as said TROWAL slowly starts to weaken with time (occlusion of the low i.e. loss of Gulf moisture). As this happens, expect the transition over to lake enhanced snowfall across the area, and eventually to pure lake effect by Wednesday night. Recent guidance has shifted the winds more north-northwesterly this morning, which in turn would bring a little more snowfall to the north-central as it would have more Lake Superior fetch to work with. In addition, with -15C 850mb air moving over 5C Lake Superior sfc waters, some guidance is picking up on some modest MUCAPE values, potentially even up to 100 J/kg. Thus, while not expected, there is up to a 10 to 15% chance that some thundersnow will be realized over the north-northwest snowbelts Wednesday into Thanksgiving morning in the lake enhanced to lake effect snow bands. Given the strong delta-Ts and troughing persisting through Thanksgiving, moderate to heavy lake effect snowfall and blowing snow looks to continue through the holiday. Thus, given the system and lake enhanced/effect snowfall, some spots over the western U.P. could see 2 to 3+ feet of snowfall before the end of the Thanksgiving weekend. Meanwhile, areas of the north central and east could see 6 to 24 inches, with some spots potentially seeing over 24+ in the east (I would suspect between Marquette and Munising). Overall, thinking this will be a storm to remember, especially for the west. If you can, get your Thanksgiving travel and shopping done today; you do not want to be out in this tonight through Thanksgiving as travel will be very difficult to downright impossible at times. If you are going to travel, take it slow and make sure to bring some water, food, a flashlight, and a blanket with you in case you get stuck; conditions will be ideal for car accidents. Also, some power outages aren't out of the question either given the strong winds. If you do experience an outage, be prepared for the power to be out for several hours as the hazardous winter weather will persist for at least a couple of days. Some minor lakeshore flooding is also possible along the Lake Superior shoreline late tonight through Thanksgiving given the strong winds and waves from the lake.

As the troughing weakens late this week into this weekend, expect the lake effect snow to lighten up over the north-northwest snow belts Thursday night through Friday night, with the lake effect snow potentially even ending over the west half by Saturday morning. Looking ahead, it does seem like we will have another shortwave bring some accumulating snowfall to the area late this weekend; however, the impacts don't look to be nearly as significant in comparison to the storm that's incoming today/tonight. Expect the colder than normal temperatures to persist into early next week.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 734 AM EST Tue Nov 25 2025

Flight restrictions to prevail at all TAF sites for duration of TAF period as winter storm enters the region. Currently rain showers and upslope fog are resulting in IFR/LIFR conditions at CMX and SAW, and IWD is expected to follow shortly as well. From this point on, do not expect any improvement. As the rain intensifies and then transitions to heavy snow late this afternoon, LIFR/VLIFR will become predominant at all sites. In addition, strong northeasterly winds will gust to 40 kts at IWD and CMX and up to 25 kts at SAW, creating a blowing snow/visibility threat in combination with fog.

MARINE

Issued at 418 AM EST Tue Nov 25 2025

As two shortwaves, one moving through the Northern Plains and one lifting from the Mid-Mississippi Valley, phase with one another today over the Upper Mississippi Valley, the winds over Lake Superior will progressively increase from the northeast, with the far west starting to see gales to 35 kts potentially as early as late this afternoon. As the phasing and deepening low lifts towards the lake tonight, expect the winds to progressively back to the north with time, increasing to gales of 35 to 45 kts, with a few storm force gusts possible over the north central late tonight (40 to 60% chance). As the low moves through the eastern lake Wednesday and lifts towards northern Quebec later in the day, expect the winds to become more north-northwesterly in the wake of the low. While winds look to weaken over the western lake Wednesday night, the high- end gales (with potentially a few storm force gusts) looks to continue into Thanksgiving. As the troughing pattern weakens Thanksgiving through late this week, expect the winds to lighten up with time, with the gales finally ending late Thursday night. Throughout the gale event, some light freezing spray will be possible across the waters from late Wednesday through Thursday evening. In addition, expect waves of 12 to 18 feet across the waters, with some areas near the tip of the Keweenaw, near Stannard Rock, and from Marquette to Grand Marais, MI potentially seeing wave heights or 20+ ft. Winds continue to weaken through Friday, eventually becoming 20 kts or less by Friday night. The light winds look to continue until Sunday when a shortwave lifts back into the western Great Lakes region.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Storm Warning from 7 PM EST /6 PM CST/ this evening to 7 PM EST /6 PM CST/ Wednesday for MIZ001>004-009-010-084.

Lakeshore Flood Advisory from 4 AM Wednesday to 1 PM EST Thursday for MIZ001.

Lakeshore Flood Advisory from 1 AM EST /midnight CST/ to 7 PM EST /6 PM CST/ Wednesday for MIZ002-009.

Lakeshore Flood Advisory from 7 AM Wednesday to 1 AM EST Thursday for MIZ003.

Lakeshore Flood Advisory from 7 AM Wednesday to 1 PM EST Thursday for MIZ005.

Winter Storm Warning from 7 AM to 10 PM EST Wednesday for MIZ005.

Winter Storm Warning from 10 AM Wednesday to 7 AM EST Thursday for MIZ006.

Lakeshore Flood Advisory from 1 PM Wednesday to 1 AM EST Friday for MIZ006.

Winter Storm Watch from Wednesday afternoon through Thursday evening for MIZ007-013-014-085.

Lakeshore Flood Advisory from 1 AM Thursday to 1 AM EST Friday for MIZ007.

Lake Superior... Gale Warning from 4 PM Wednesday to 1 AM EST Friday for LSZ251- 267.

Gale Warning from 3 PM EST /2 PM CST/ this afternoon to 7 AM EST /6 AM CST/ Thursday for LSZ162.

Gale Warning from 10 PM EST /9 PM CST/ this evening to 7 AM EST /6 AM CST/ Thursday for LSZ240>242.

Gale Warning from 10 PM this evening to 1 PM EST Thursday for LSZ243-246.

Gale Warning from 10 PM this evening to 7 PM EST Thursday for LSZ244-245-264-265.

Gale Warning from 1 AM Wednesday to 1 PM EST Thursday for LSZ247-248.

Gale Warning from 10 AM Wednesday to 1 AM EST Friday for LSZ249.

Gale Warning from 1 PM Wednesday to 1 AM EST Friday for LSZ250.

Gale Warning from 7 PM this evening to 1 PM EST Thursday for LSZ263.

Gale Warning from 1 AM Wednesday to 1 AM EST Friday for LSZ266.

Lake Michigan... Gale Warning from 4 PM Wednesday to 1 AM EST Friday for LMZ221- 248-250.