textproduct: Marquette

KEY MESSAGES

- Small rain chances continue tonight...ending west to east.

- Warmer Wednesday with additional (much needed) rain chances Wednesday night.

- Dry and turning breezy/colder Thursday.

- Unsettled to start next week? Uncertainty abounds...

DISCUSSION

Issued at 240 PM EDT Tue Oct 27 2026

Pattern Synopsis: Split flow pattern across North America...with the Great Lakes mainly under the influence of southern branch flow emanating around a mean trough across western North America. Long wave ridge axis extends north from the Gulf...through the Midwest and into central Canada. There is also an old upper low northeast of Hawaii that may have some impacts for the start of next week. Water vapor imagery shows several short wave troughs propagating through the western long wave trough...one lifting into northwest Ontario this afternoon with a second on its heels tracking into Iowa/Missouri. Farther upstream additional pieces of energy across Montana/Wyoming and along the Oregon/ northern California coast. Elongated band of deeper moisture (precipitable water values around 1.25 inches) extends north from the western Gulf into the upper Lakes...dynamic forcing with short wave troughs/right entrance region jet forcing interacting with this narrow moisture plume generating showers from western Upper/ Minnesota/western Wisconsin southward into Iowa/ eastern Kansas. At the surface...1035mb high centered over northeast Ontario bringing east/southeast boundary layer flow into the region...though with veering winds quickly above the surface indicative of low level warm advection. 1018mb surface low over southwest Minnesota with a warm front extending southeast into the Ohio Valley...and a trailing cold front across Iowa/Kansas.

Primary Forecast Concerns:

Small rain chances continue tonight...ending west to east: Not much out there at mid afternoon...better shower coverage just scraped by IWD before lifting north...and activity across Wisconsin is pretty spotty even with the best jet forcing in place (which will wane this evening). Even with things drying out aloft overnight do have some concerns about lingering low level moisture and perhaps some drizzle developing across the western third of Upper Michigan overnight.

Warmer Wednesday with additional (much needed) rain chances Wednesday night: It will be warmer...to what magnitude is the question Consensus NBM forecast highs are really enthusiastic (lots of upper 60s and lower 70s). There is still a lot of cloud cover out there and concerned that especially over western Upper this could tamp temperatures down. Have added in some raw temperature guidance to the NBM to tone things down a touch...still have highs in the lower to mid 60s which is pretty good considering our normal highs now in the mid to upper 40s. Think the eastern half of Upper Michigan stands the best chance for seeing some more sun Wednesday. Better rain chances in the cards by late Wednesday afternoon/night ahead of an approaching cold front and a narrow low level theta-e ridge axis. Anticipating a band of showers and some embedded thunderstorms with instability within the theta-e ridge. Should be a quick hitter as rain threat expected to be east of the forecast area by mid-Thursday morning. Overall rainfall amounts generally 0.25 or less on average...but better than nothing.

Dry and turning cooler Thursday: Cold front will sweep across the Upper Peninsula by Thursday morning...with winds shifting to the west and northwest as cooler air invades from the northwest. High temperatures may be earlier in the day Thursday and may see temperatures cool during the afternoon. Should be a bit breezy as well...with winds diminishing Thursday night as high pressure builds into the Great Lakes from the west.

Unsettled to start next week? Uncertainty abounds: Earlier mentioned upper low northeast of Hawaii may make an appearance over the central/southern Plains this weekend...at least what remains of it by then. Whether we see any rainy impacts from this feature during the latter half of the weekend and into Monday is uncertain. There will be low chance PoPs in the forecast for some areas Sunday and Monday given the possibility that we could see some rain push into Upper Michigan to end the weekend...though right now the probability appears to be small. The high that builds into the Great Lakes Friday is forecast to move into New England by Saturday...a return to more southerly winds should keep temperatures above normal through the weekend...keeping the very warm October theme intact until the very end.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 229 PM EDT Tue Oct 27 2026

Generally E/SE winds 5-15kts this afternoon and evening turn to S overnight...and will drop back to 5 to 10kts. Think LLWS will occur this evening til around 09-12Z...with SW winds around 30-40kts at 2000ft AGL. Winds 5-10kts after 12-15Z from SW at all sites. MVFR to VFR ceilings likely this afternoon into early tonight...but do have concerns IFR/MVFR could continue longer than expected. Otherwise ceilings should return to IFR/MVFR after 06-09Z or so...with slight improvements into the morning. SHRA threat remains through this evening and again toward 06-09Z. KSAW least likely to see SHRA through this TAF period.

MARINE

Issued at 240 PM EDT Tue Oct 27 2026

Lake Superior: Southeast winds will veer around to the south and even southwest across the western half of the lake overnight. Winds will also increase for a time during the first half of the night (gusting to 30kts across eastern Lake Superior) before low level warm advection and a shrinking mixed layer depth will allow winds to diminish a bit overnight. Gradient winds will pick up again Wednesday night ahead of a passing cold front...again dealing with a shallow (which may be generous to call it that) mixed layer with 925mb temperatures warmer than water temperatures. Low level jet forecast of 40-50kts over eastern Lake Superior...but have to imagine that momentum only exists in the guidance due to boundary layer stability...and is not going to be there for the taking. Mechanical/turbulent mixing could still bring about gale force wind gusts across the eastern half of the lake. By Thursday morning cold frontal passage will veer winds around to the west...with cold advection and decreasing boundary layer stability allowing for a more efficient momentum transfer and perhaps more gusts to gale force. Winds will diminish Friday as a 1028+mb high builds into the Great Lakes.

Northern Lake Michigan and northern Bay of Green Bay: Southeast winds this afternoon veer more southerly this evening...waves will increase on northern Lake Michigan due to the longer fetch but anticipating conditions to remain below Small Craft Advisory. Higher impact winds/waves likely Wednesday night ahead of a cold front... south to southwest winds to 25kts with wave heights west of Seul Choix Point to around 5 feet. Winds will veer to the northwest Thursday morning behind the passing cold front...with winds diminishing Friday as high pressure builds in and the gradient weakens.

MQT WATCHES/WARNINGS/ADVISORIES

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