textproduct: Marquette

KEY MESSAGES

- A brief lull in precipitation occurs tonight before returning Thursday, mainly north.

- Lake enhanced rain transitions to lake effect and upslope driven snow over the north to northeast wind precipitation belts Thursday night into Friday.

- Light snow accumulations are becoming increasingly likely Thursday night through Friday morning with isolated amounts >1" possible (50- 80% chance) in areas of high terrain in the west and central UP.

- A Gale Warning is now in effect for northerly gales of 35 to 45 knots across most of Lake Superior Thursday. Strongest winds over the central waters.

DISCUSSION

Issued at 311 PM EST Wed Nov 4 2026

Afternoon GOES satellite imagery reveals a nearly vertically stacked upper low slowly spinning over the MN/WI border. The juxtaposition of this feature has placed the UP within the system's dry slot, shunting the near record PWAT values north into Canada. A few scattered showers are lifting across the UP as weak diurnal instability has managed to build behind the nose of the dry slot. Once these showers lift north, a lull in precip is expected to occur through the evening. Tonight through Thursday morning, the parent closed upper low begins to open as it is gobbled up by a descending trough out of northern Ontario. This works to translate the attendant surface low north and east of Lake Superior, bringing the system's deformation driven precipitation overhead and introducing another round of rain to the northern tier of the UP. A secondary shortwave pinwheels around the ascending trough, digging across the UP Thursday through early Friday, reinforcing a shot of cold air characterized by 850 mb temps falling between -3 to -6C over a ~+9C Lake Superior sfc temp average. Lake enhanced rain will transition to pure lake effect snow as deformation driven precip exits east and lake induced delta Ts rise to 13C through Thursday afternoon. This transition will likely occur faster over the western UP where sfc temps fall into the low 30s and the interior remains away from the lake modified warmer airmass, but there will likely be a period of rain/snow mix as this happens. Further east, lake effect rain may be the only precip type as gusty N to NE winds off the lake keep the area warmer. At the same time, the aforementioned cold air advection and sharp pressure rises behind the departing low (near 1 mb / hr possible in the central lake), will quickly ramp up N to NNE winds Thursday morning. Gusts between 35-45 mph will be common along the shorelines of Lake Superior, gradually falling off from west to east through Friday morning. The biggest question of this forecast period remains "how much snow" given this is the first measurable snow event of the season. As the transition to lake effect snow occurs Thursday afternoon, Bufkit soundings reveal lake induced inversion heights peaking between 6-8k ft with good moisture throughout the low levels, however, the lake inversion either stays below the DGZ or barely scrapes it for less than 3 hours, pointing toward low SLRs (likely 10:1 or less) and overall sloppy snow quality made lower by crystal fracturing in gusty winds. Interestingly, some CAMs reveal a Lake Nipigon connection band impacting portions of Ontonagon/Gogebic counties that may provide an extra boost to snow production where it sets up. Pattern recognition suggests that the central UP highlands of Baraga/Marquette county will ultimately be the "winner" in terms of accumulating snow as precip is largely driven by upsloping. By Friday morning, a dusting to maybe an inch of wet snow is most likely across the west away from the lakeshores while the Michigamme Highlands tally 1-2" (50-80% for this solution per REFS and NBM). The 12z REFS PMM paints 2-4" of snow across the central highlands, but deciding to remain conservative with this snowfall forecast. While I would love to see the 12z HRRR solution pan out at the office (10"), thinking the lack of DGZ access and approaching dry air eating away lake inversion heights makes that particular solution a bit bullish.

Building ridge and local high pressure returns drier and warmer than normal conditions this weekend into early next week.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1234 PM EST Wed Nov 4 2026

Poor flying conditions persist this morning and for the duration of this TAF period as a low pressure system moves through the area. IWD and CMX have briefly improved to MVFR for now, but do not expect that to last. Will continue to trend to predominantly IFR/LIFR conditions throughout the TAF period with little shift in this pattern. Periods of rain will continue to impact all TAF sites through tomorrow. Meanwhile, east to southeast winds become south today between 5 to 10 kts, then becoming northwesterly by tonight at IWD and CMX with frontal passage. Wind gusts of 20 to 25 kts will accompany the wind shift.

MARINE

Issued at 311 PM EST Wed Nov 4 2026

Lake Superior: Gale Warnings remain in effect early Thursday morning through early Friday morning as strong pressure rises and stout cold air advection bring a sharp increase in winds. N to NNE winds increase to gales of 35-45 kts in the western lake between Isle Royale and the Keweenaw early tomorrow morning. These gales transition across the central and eastern lake through the morning to early afternoon hours, building significant wave heights upwards of 15 ft. Building high pressure diminishes winds and waves from west to east overnight through Friday morning.

Northern Lake Michigan and northern Bay of Green Bay: Breezy southerlies between 20-25 kts will be the rule through thursday morning before a sharp cold front veers winds to the north, increasing gusts between 25-35 kts by the afternoon. A brief Gale Warning has been issued for our Green Bay and N Lake Michigan zones between 18z Thursday through 03z Friday. Gales fall off overnight becoming winds 20-30 kts through early Friday.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning from 4 AM EST /3 AM CST/ to 7 PM EST /6 PM CST/ Thursday for LSZ241-242-263.

Gale Warning from 4 AM to 10 PM EST Thursday for LSZ243-244- 264.

Gale Warning from 7 AM Thursday to 1 AM EST Friday for LSZ245>248-265-266.

Gale Warning from 10 AM Thursday to 1 AM EST Friday for LSZ249- 250.

Gale Warning from 1 PM Thursday to 7 AM EST Friday for LSZ251- 267.

Lake Michigan... Gale Warning from 1 PM to 10 PM EST Thursday for LMZ221-248- 250.