textproduct: Marquette

KEY MESSAGES

- Weak clipper system will provided light snow chances this weekend with lake effect snow following for the NW wind snowbelts.

- Colder than normal temperatures continue through the forecast.

DISCUSSION

Issued at 257 AM EST Fri Dec 5 2025

Early morning RAP analysis and water vapor imagery indicate broad NW flow aloft with an embedded shortwave dropping into the Great Lakes. This is to be a recurring theme for much of the extended period. Down towards the surface, low pressure is analyzed over Ontario, with a diffuse frontal boundary extending SSW through Minnesota and South Dakota. Out ahead of this, light snow has been able to develop across much of the UP with widespread weak radar returns and plenty of ASOS sites ticking off some snowflakes. The heaviest radar returns are over the eastern UP (perhaps some enhancement due to the proximity of the right-entrance region of the LLJ, or the long fetch off of Lake Michigan?), so another 1-2in would not be out of the question there the rest of the night. For its part, the HREF favors snowfall rates of up to a half and even 1in/hr, with around a 30-40% chance for snowfall rates in excess of 1in/hr at times into the pre- dawn hours. This, in combination with gusty winds particularly near the lakeshores, could lead to some blowing snow and a potential for some hazardous travel ahead of the morning commute. Take it slow and mind your stopping distance! Elsewhere, snowfall amounts the rest of tonight stay below an inch. Temperatures thus far in the teens may fall back further just below 10F.

Snowfall largely wraps up after sunrise, with just some lingering lake bands possibly bisecting the Keweenaw as winds remain out of the SSW ahead of another approaching clipper-like wave (currently over the Dakotas). Temperatures climb into the lower/mid 20s under cloudy skies. The next wave looks to track through northern Wisconsin later this evening through the first half of the night, providing another round of light "system" snow over the southern and eastern UP, followed by a reinforced shot of cold air and light lake effect snow to the northwest wind snowbelts through the rest of the weekend. At this time, lake effect snow aims to be on the lighter side, potentially providing the NW wind snowbelts with an additional 1-3in despite supportive delta-Ts pushing 25C given dry air within the boundary layer. Will note a potential for higher totals in the 3- 6in range over the Keweenaw by in the weekend given the potential for any heavier banding to extend into the area. Meanwhile, temperatures come in much cooler, peaking only in the teens Saturday and Sunday and falling into the single digits (or lower!) each night.

Looking further into the midweek period, operational models and their ensemble counterparts continue the NW flow aloft clipper train across the area, supporting additional periods of accumulating system and lake effect snow.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 640 AM EST Fri Dec 5 2025

MVFR conditions are observed at all sites this morning and are expected to be the primary flight category for this TAF period. With system snowfall pushing east and out of the region today, NW wind lake effect snow showers will impact the TAF sites to varying degrees. The heaviest impacts will most likely be felt at CMX, with NW gusts in excess of 25 kt tonight driving visibility down, with 40% chances of IFR visibility late this evening into the overnight hours. Like any LES setup, periods of VFR in between bands/cells of SHSN are possible but have a high degree of uncertainty associated with them and are unlikely to prevail for a full hour.

MARINE

Issued at 257 AM EST Fri Dec 5 2025

SW gales to 35-40kts persist early this morning, tapering off around 12Z. Winds remain elevated the rest of the day, however, with gusts to near 20-25kts. Saturday morning, post-frontal northwest winds will ramp up to 30 kt, with chances of a brief 35 kt gale around 40 percent. The weather pattern into next week looks to continue with periodic Clipper Lows that will bring either increased southwest winds ahead of it and/or gusty northwest winds in its wake.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning until 7 AM EST this morning for LSZ243>251- 264>267.

Lake Michigan... Gale Warning until 7 AM EST this morning for LMZ221-248-250.