textproduct: Marquette

KEY MESSAGES

- Aside from lingering light snow showers through tonight over the far eastern UP, dry weather is expected through Wednesday with highs near normal in the 30s/40s and lows in the teens/20s.

- Next period of widespread precipitation is expected Thursday, mainly in the form of light rain.

DISCUSSION

Issued at 211 PM EST Mon Nov 17 2025

Confluent northwesterly midlevel flow over the local area this afternoon is promoting an elongated ridge of high pressure from northern Manitoba southeastward into the western half of the UP. Meanwhile, northwesterly boundary layer flow continues to generate lake effect clouds over the east half, with a few light snow showers over portions of Luce County (although the more persistent echoes have remained east toward the Soo). Lake surface to 850 mb delta-Ts of ~17C continue to be favorable for these lake effect processes, although inversion heights limited to 5kft and the convective layer well below the dendritic growth zone will continue to limit any accumulations to a nuisance at most. This pattern will continue into tonight before the ridge expands over the east tomorrow, although some stubborn lake effect clouds may linger over the east. High confidence that precipitation associated with a strong, compact shortwave ejecting out of the intermountain west will remain to our south on Tuesday, with the ridge of high pressure gradually shifting east on Wednesday as midlevel flow becomes more zonal.

Wednesday night into Thursday, a northern stream trough will dig from the Canadian Prairies into the upper Great Lakes. Warm advection and DCVA is likely to force a band of mainly rain showers from possibly late Wednesday night into Thursday, although there is still uncertainty with the timing. If showers can work their way in as early as late Wednesday night, a few patches of freezing rain (or more likely, freezing drizzle, based on low-level saturation below a midlevel dry layer on some forecast soundings) cannot be ruled out before strong warm advection brings everyone above freezing on Thursday. The chance of this appears to be only 20-30% at the moment so not worth messaging at this time, but will continue to monitor. Otherwise, the bulk of the shower activity should be during the day Thursday along/ahead of the system's cold front, with the postfrontal airmass likely just cold enough to support light lake effect snow showers over the east Thursday night into Friday.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1202 PM EST Mon Nov 17 2025

VFR conditions expected across Upper Michigan with mostly clear skies the rest of today and only a slight increase in mid/upper level cloud cover into Tuesday. NW winds of 5-10 kt will also become lighter through the day as high pressure builds into the region.

MARINE

Issued at 222 AM EST Mon Nov 17 2025

Encroaching high pressure has already ended gales across Lake Superior, though northwest wind gusts will remain above 25 kt until the mid morning hours today. Wind gusts fall below 20 kt overnight tonight into Tuesday. Significant wave heights this morning will fall to 4-7 ft for the east half (less in the west) and below 4 ft overnight tonight into Tuesday lakewide. High pressure will then keep wind gusts sub-20 kt until at least the late-week period. Then, attention turns to multiple potential shortwave troughs that could spawn surface low pressure systems. Confidence is low in the details, but there is a 15-25% chance that a low pressure feature could be accompanied by gale-force gusts.

MQT WATCHES/WARNINGS/ADVISORIES

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