textproduct: Marquette

KEY MESSAGES

- A major winter storm will impact the UP tonight through Monday, with the worst conditions overnight into Monday morning. Heavy snow and high winds will result in very difficult to impossible travel conditions, with blizzard conditions resulting in near-zero visibility at times. Strong winds and heavy snow have the potential to result in power outages. Blizzard Warnings are in effect for most of the UP this evening through Monday.

- The heaviest snow is expected in the counties bordering Lake Superior, where there is a 70-100% chance of exceeding a foot of snow, locally up to two feet. Wind gusts of 40-60 mph are expected near the lakeshore and Keweenaw, with 35-50 mph expected inland.

- From Iron through Delta Counties, there is a 40-80% chance of exceeding 8 inches of snow, locally up to 15 inches.

- Light freezing rain cannot be ruled across the eastern UP this morning, and again this evening before a transition over to snow. A light glaze to a tenth of an inch is possible (40% chance).

- Gale and Storm Warnings are in effect tonight into Monday night. There is a 70-90% probability of storm force winds over the central and eastern lake, with gusts as high as 60 kt possible.

DISCUSSION

Issued at 449 AM EST Sun Dec 28 2025

Early this morning, RAP analysis reveals broad midlevel troughing over the Plains, with surface low pressure deepening over KS as a vort max rounds the base of the midlevel trough. A rather steep baroclinic zone extends northeastward from this through central and northern IL, with temperatures ranging from around 60F near Springfield to 40F near Rockford. Meanwhile, another embedded shortwave/closed low is dropping over the Dakotas. Closer to home, we've "enjoyed" a night of patchy rain showers/drizzle courtesy of a weak passing shortwave and overrunning weak WAA. With plenty of lower level moisture and light winds, patchy fog has developed over much of the UP, dense at times particularly across the central portions of the CWA. Temperatures are hovering right around freezing, so some slick spots on roadways would not be out of the question due to some freezing fog, and even some ice light accumulations out in the eastern UP where radar echoes are more "impressive" at around 30dbz. Still, with significant icing unlikely, will not issue any headlines for this earlier potential this morning.

All eyes are then on a classic winter storm set to provide heavy snow, high winds, and difficult to impossible travel conditions for the UP this evening through Monday. Our Plains low begins to track northeast into the UP this afternoon while the aforementioned northern shortwave continues to drop southeastward. This puts upper MI squarely in the crosshair for upper level diffluence, with the exit region of the upper jet directed over the Great Lakes. These strong dynamics are expected to result in rapidly deepening surface low pressure along the preexisting baroclinic zone, with very impressive deepening rates near 24 mb in 24 hours progged from 12Z Sun through 12Z Mon by tonights global model suites (1000 mb to ~upper 970s). These values flirt with climatological minimum of MSLP in both the NAEFS and EPS. In terms of raw values, WPC's minimum MSLP database shows all time December mins around 970 around the path of the low, so while it may not be record setting, its climatological context puts it toward the stronger end of winter storms for this area.

Latest hi-res, global, and ensemble guidance is now keying in on a storm track from southern Lake Michigan this evening to somewhere over central or northern Lake Huron by early Monday. In spite of these minor differences in track, confidence remains high in major winter weather impacts with heavy snow and strong winds developing tonight into early Monday.

Soundings are just warm enough as the precipitation shield lifts northward this afternoon for for precipitation to start off as rain or a rain/snow mix, then expect a rapid change over to snow from west to east this evening. Will note an elevated warm nose lingers over the eastern UP at least into the evening, so we have another opportunity for some icing before we finally change over there. There is then a period of a few to several hours after midnight where much of the column is cooling to the DGZ, while we also mix as high as 850mb and tap into the strong 45-60kt LLJ. Meanwhile, winds turn from the northeast to north as the storm makes its northeastward trek. This spells out a period of moderate to heavy snow (first starting off rather wet, then gradually turning fluffier) for all of the Upper Peninsula, with the heaviest totals across the northern UP where lake enhancement and upsloping off of Superior occur. HREF favors several hours of 2in+ per hour snowfall rates, with the highest rates and longest-duration across the north- central UP from around midnight to 6am.

NBM guidance continues to show as much as a 50-100% chance for snow totals in excess of a foot for all but the south-central UP. Also highlighted is around a 75-85% chance for totals in excess of 18 inches across northern Baraga, marquette, Alger, and Luce counties - generally along/north of M-28 and across US-41. Another such bullseye exists across western Ontonagon and Gogebic counties. These heavier totals reflect both the terrain and lake enhancement, and in fact this latest forecast has adjusted totals upward to around 18-24 inches in those locations. A more widespread 10-15inches is expected across most of the remainder of the UP, with around 8-12in across Menominee, Dickinson, and Iron counties.

Winds crank up after midnight, with gusts of 30-40mph common across the southern half of the UP and stronger gusts of 40-50mph (or higher!) as one heads northward towards Superior. 50-60mph gusts will be possible across the Keweenaw for several hours Monday morning. Winds slowly fall back Monday afternoon and evening as the storm pulls away.

Given the strong winds, blizzard conditions are expected, resulting in significant impacts to travel tonight through Monday afternoon. Travel Monday morning is strongly discouraged except for emergency situations. Blizzard Warnings continue for all UP counties, except Iron, Dickinson, and Menominee, where Winter Storm Warnings continue. Model soundings mix into the 45-55 kt LLJ as far south as Menominee, so its entirely possible the Blizzard Warning may be further expanded south based on trends and coming observations. Lakeshore Flood Advisories are also in effect for counties along Lake Superior where waves 15-20 feet may create flooding and beach erosion hazards.

As the storm pulls away, snow tapers off from west to east Monday afternoon into Monday night. There are indications that a quick- hitting clipper moves back in on Tuesday, which would result in a bit more light snow, but perhaps more importantly, heralds a reinforcing shot of Arctic air for the New Year holiday. LREF mean shows 850 mb temps in the low -20s (C), which is around the 10 percentile. This would result in wind chills well below zero for the New Year's Holiday, along with northwest flow lake effect snow.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 657 AM EST Sun Dec 28 2025

IFR/LIFR conditions are already impacting all TAF sites early this morning as fog/freezing fog reduce visibilities. And, conditions are not expected to impove as a very strong system remains on track to cross the region tonight. Therefore, LIFR and possible airport mins will prevail for the duration of this TAF period, especially as northerly winds increase to 35 to 50 kts tonight. This will result in blizzard conditions and near zero visibilities at times. Strongest winds will be at CMX where gusts in excess of 50 kts are expected. And, IWD and SAW will also have gusts in the 35 to 40 kt range. Any rain/snow mix this morning will transition to all snow through the course of this afternoon as colder air overspreads the area.

MARINE

Issued at 449 AM EST Sun Dec 28 2025

High-impact marine weather is set to occur late today into Monday night as an unusually strong low pressure quickly strengthens over the western Great Lakes and moves into Quebec. Northeast gales quickly develop this evening, then winds gradually back to the N and NW into Monday. There is a moderate to high (60-90%) probability of storms out of the north to northwest over the central/eastern lake late tonight into Monday, with gusts up to 60 knots possible. Risk of significant waves exceeding 20 feet from the experimental National Blend of Models is 70-90 percent east of Marquette toward Pictured Rocks, possibly up to 28 feet, with 12-20 feet elsewhere. Heavy freezing spray and limited visibility in heavy snow is also expected.

Gales end from west to east Monday night, but a reinforcing shot of Arctic air across the lake is expected to result in northwesterly gales and heavy freezing spray at times Tuesday night to the end of the week, especially over the central and eastern lake.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Blizzard Warning from 7 PM this evening to 7 PM EST Monday for MIZ001-003>007-084.

Lakeshore Flood Warning from 1 AM to 7 PM EST Monday for MIZ001.

Blizzard Warning from 4 PM EST /3 PM CST/ this afternoon to 4 PM EST /3 PM CST/ Monday for MIZ002-009.

Lakeshore Flood Advisory from 1 AM EST /midnight CST/ to 7 PM EST /6 PM CST/ Monday for MIZ002-003-009.

Lakeshore Flood Warning from 1 AM Monday to 1 AM EST Tuesday for MIZ005-006.

Lakeshore Flood Advisory from 8 AM Monday to 1 AM EST Tuesday for MIZ007.

Winter Storm Warning from 6 PM this evening to 6 PM CST Monday for MIZ010>012.

Blizzard Warning from 10 PM this evening to 7 PM EST Monday for MIZ013-014-085.

Lake Superior... Gale Warning from 7 PM EST /6 PM CST/ this evening to 10 PM EST /9 PM CST/ Monday for LSZ162-240-241.

Heavy Freezing Spray Warning from 10 PM EST /9 PM CST/ this evening to 1 AM EST /midnight CST/ Tuesday for LSZ162.

Heavy Freezing Spray Warning from 1 AM EST /midnight CST/ Monday to 7 AM EST /6 AM CST/ Tuesday for LSZ240>244-263- 264.

Storm Warning from 7 PM this evening to 10 PM EST Monday for LSZ242>244-263-264.

Storm Warning from 10 PM this evening to 1 AM EST Tuesday for LSZ245>251-265>267.

Heavy Freezing Spray Warning from 3 AM Monday to 7 AM EST Tuesday for LSZ245>251-265>267.

Lake Michigan... Storm Warning from 1 AM Monday to 1 AM EST Tuesday for LMZ221- 250.

Heavy Freezing Spray Warning from 2 PM Monday to 5 AM EST Tuesday for LMZ221.

Gale Warning from 1 AM Monday to 1 AM EST Tuesday for LMZ248.