textproduct: Marquette

KEY MESSAGES

- Widespread light rain this morning gives way to lingering lake effect rain showers tonight and Thursday.

- Another round of rain is expected Friday, followed by lake effect and enhanced snow into the weekend.

- Temperatures running slightly above normal the rest of the work week trend colder this weekend onwards.

DISCUSSION

Issued at 343 AM EST Wed Nov 5 2025

Morning RAP analysis shows a shortwave tracking into the Great Lakes, with a surface low analyzed over northeastern WI. This has brought an initial batch of light rain to the UP overnight, which is starting to pull out of the western half of the UP as the system continues its eastward trek. CAMs continue to hint at another broken line of rain showers moving through over the next few hours as another weak boundary drops through.

Winds will pick up into this afternoon with a strengthening pressure gradient, pressure rises, and colder airmass descending overhead. Widespread northwest winds between 10-20 mph are expected with gusts between 20-30 mph. Stronger gusts up to 30-40mph are not out of the question along Lake Superior in the eastern UP (50% chance). As 850 mb temps fall to between -6C and -9C by the end of the day, scattered lake effect rain showers kick off over the eastern and north-central UP, possibly mixing with or even changing entirely over to snow in the interior tonight. Elsewhere, expect dry and partly cloudy weather the rest of today as ridging recovers, allowing for dry weather to continue for most of Thursday. Meanwhile, temperatures today peak in the mid 40s for most, falling back into the 20s to near 30F tonight before rebounding into the 40s Thursday.

Another clipper system looks to bring light rain Thursday night into Friday. In the wake of this system, there is increasing consensus that an extension of the Hudson Bay upper low will dip south into the Great Lakes, likely resulting in the coldest airmass of the season thus far. The NBM currently reflects this with highs in the upper 20s to 30s and lows in the upper teens to low 30s this weekend into Monday night. With 850mb temps dropping to -10C to -14C and some solutions showing as low as -16C, delta-Ts will be more than sufficient for north to northwest lake effect precip during this period...initially rain/snow mix transitioning over to mostly snow by Sunday/Monday. Another high pressure looks to follow early next week, diminishing PoPs, but confidence is low on the track and influence of this feature at this time.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 620 AM EST Wed Nov 5 2025

Light rain showers are pressing east with a passing disturbance moving south of the UP this morning. MVFR/VFR conditions are expected at all sites before becoming all VFR through the morning and into the afternoon as the system departs. Lake effect clouds and precip may linger in the east half, but should remain VFR through the rest of the TAF period. Otherwise, the main aviation hazard today will be gutsy NW winds ramping UP this early afternoon and persisting through the evening. Gusts 25-35 kts will be common, especially at CMX.

MARINE

Issued at 343 AM EST Wed Nov 5 2025

Winds below 20kts early this morning quickly increase towards sunrise behind an exiting, strengthening low pressure system. Widespread northwest winds are expected between 20-30 kts with strongest winds over the east, particularly near the southern shores. Latest probabilistic guidance for gales of at least 35 kts shows 20-50%, highest along the southern shores between Au Train and Whitefish Point, decreasing as you move away from those nearshore zones. Have decided to upgrade to a Gale Warning for this afternoon into the first half of tonight in spite of the relatively lower confidence in achieving gales, given the healthy shot of cold air advection behind the system. Gales quickly fall off around midnight, then winds decrease to near or below 20kts Thursday morning before picking up again Thursday evening. There is around a 30% chance of gales returning Friday into Friday night as an even colder airmass descends over the lakes. Winds remain elevated this weekend into early next week.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning from noon today to 10 PM EST this evening for LSZ249>251-266-267.

Lake Michigan... None.