textproduct: Marquette

KEY MESSAGES

- Lake effect rain showers become widespread this afternoon and transition to snow tonight.

- An extended period of lake effect snow is expected for tonight into Saturday. The most impactful periods look to be during the overnight and early morning hours, especially Thursday night into Friday.

- Snowfall of 4-8" is expected for the tonight through Friday period over the higher terrain of Marquette and Alger counties with 1-3" elsewhere (expect less close to Lake Superior, Menominee County and the Eastern U.P.). There is a 60% chance for snowfall exceeding 10" in the highest terrain, along and west of the Dead River Basin.

- Temperatures rebound to unseasonably warm 50s early next week.

DISCUSSION

Issued at 310 AM EST Wed Nov 11 2026

Early this morning GOES water vapor imagery and GFS 500mb model height analysis showed an upper level low over northern Quebec which had retrograded westwards from Newfoundland over the last 24 hours. Shortwaves continued to rotate around this low while another shortwave originating in Alberta was moving through southern MN. The better forcing with this shortwave was remaining further south and west of the area so far, keeping the area dry with high level clouds overspreading the U.P. The delay in mid-level cloudiness along with light winds was helping temperatures cool into the upper 20s and 30s away from the lakeshore. Isolated areas of dense fog had formed but this should diminish towards sunrise as cloud cover thickens and temperatures begin to rise.

The main challenge with the forecast through the end of the week will be a favorable setup for lake effect snow as north-northeast flow develops over the region and cold air advection increases.

The upper level low over northern Quebec will continue to move southwest to near Lake Huron through Friday with multiple shortwaves rotating around the low over the Upper Great Lakes. Scattered rain showers, mainly over the southern U.P. are still possible (50% chance) through mid-morning but thereafter a cold front will push south across the area as the next shortwave drops south out of Ontario. Expect temperatures (40s) to slowly fall this afternoon over the northern U.P. and lake effect rain showers to become widespread as 850mb temperatures fall to -3 to -5C bringing sufficient lake-850mb deltaTs (greater than 13C).

The greatest impact period starts late this evening as low levels continue to cool bringing 850mb temps down to -6 to -8C and sfc temperatures fall to around freezing over the western and central U.P., away from the Lake Superior shoreline. The main challenges with this forecast is temperatures, snow ratios, snow intensity and accumulations. There is enough confidence to issue a Winter Weather Advisory as snowfall of 4-8" looks likely (80% chance) over the higher terrain of Marquette and Baraga counties, with the high end of the range in the higher terrain along and west of the Dead River Basin. While this is still on the lower end of traditional criteria for a 48 hour span, the wet snow character and expected moderate rates (0.5-1.0"/hr) support an advisory. Near the Lake Superior shoreline less than an inch of accumulation is expected (Including the city of Marquette); the best chance to see any accumulations there would be Thursday night when the 850mb temps fall to near - 11C. Impacts to the area roads will be greatest during the overnight hours tonight and Thursday night but periods of heavier snow during the daylight hours will still be impactful.

For temperatures the NBM is running much too cold for overnight temperatures as it has been trained on recent stretches of cool, clear nights. Thus it has temperatures falling into the mid 20s over the interior and even below freezing at the immediate lakeshore tonight and Thursday night. This seems unlikely given the strong onshore flow, cloud cover, precip and marginally cold 850mb temps of -6 to -10C. Overall thinking is that temperatures will remain in the mid 30s overnight near the Lake Superior shoreline and much of the eastern U.P. tonight with slightly cooler temperatures Thursday night with the eastern U.P. falling to right around freezing.

SLRs also look quite a bit overdone in the NBM with 14:1 by Thursday including over the Great Lakes. This is seems unlikely given the warmer low levels and warm ground temperatures (mid 40s) going into the event. Similar thermal profiles to last week's lake effect snowfall yielded between 5:1 and 7:1 SLR. These values seem reasonable for tonight into Thursday, then approaching 10:1 Thursday night as cooling continues. A locally developed temperatures to SLR curve matches up well with this for areas away from the lake with very low SLRs. RRFS and HRRR also give confidence to the lower SLRs as they are producing lower end SLRs, ~6:1 during the daytime hours and ~10:1 at night.

While confidence is high in achieving a low end advisory scenario, confidence is low with regards to higher end scenarios. While the medium range models are producing around 0.5-0.75" QPF over the higher terrain the RRFS, HRRR and RAP are much more aggressive with 1.5 to 2.25" QPF over the high terrain of Marquette and Baraga counties. Even with lower end SLRs this would yield warning criteria snowfall of 12-16" or more. REFS probabilities for 12"+ over the advisory period are in the 30-40% range for the highest terrain. Models are converging on a solution of deeper low level moisture with inversion heights to 8-10 kft along with strong convergence over the east-central part of Lake Superior, into the Marquette County shoreline. Associated intense lake effect bands are prevalent in the aforementioned guidance. Should these band materialize SLRs may also overachieve as strong lift in the DGZ produces large dendrites, wet bulb effects and snowfall rates overwhelm (cool) the warmer low levels. Will continue to monitor trends. Current probabilities for moderate snowfall rates (0.5-1.0"/hr) are around 80% with a 30% chance for heavy snowfall rates (1"+/hr).

LES should wind down Saturday, confined mainly to northern Marquette County and Alger County during the morning hours with a few lingering rain/snow showers into the afternoon, though as is typical with LES events, wouldn't be surprised if LE showers linger longer than guidance suggests. As ridging aloft moves over the Plains, high pressure will keep Sunday through Tuesday mostly dry with temperatures warming into the 40s and eventually back into the upper 40s to lower 50s.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 656 AM EST Wed Nov 11 2026

Primarily VFR conditions hold until this afternoon when winds shift north, bringing in persistent lake effect showers. Initially these showers start out as rain, but snow begins to mix in this evening and a full change over is expected by late tonight. With the rain and rain/snow mix come periods of MVFR VIS, save for the initial burst late this afternoon which may bring a brief period of IFR VIS (~30-50% chance). IFR mention was left out due to the short duration and timing discrepancies in guidance. Toward the end of the 12Z TAF period brings more persistent MVFR VIS with periods of IFR VIS or lower in persistent lake effect snow bands (30-40% chance).

MARINE

Issued at 310 AM EST Wed Nov 11 2026

A cold front will drop south across the lake this morning into the early afternoon bringing a wind shift to the north and increasing wind speeds. North-northeast winds gust to 30kt through Thursday before starting to shift more due north and decrease to 20-25kt Thursday night (continuing into Friday evening). A few gusts to gale are expected (40-60% chance) for the higher platforms this afternoon and evening. Waves of up to 4 ft on Lake Michigan and 5-8 ft on Lake Superior are expected by Thursday morning. Waves fall below 4 ft Friday afternoon for all except the east half of the lake, with waves falling below 4 ft in the east Saturday morning. High pressure will keep winds below 20 kt and waves mostly 2 ft or less through the first half of next week.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Winter Weather Advisory from 10 PM this evening to noon EST Friday for MIZ004-005.

Lake Superior... None. Lake Michigan... None.