textproduct: Marquette

KEY MESSAGES

- Light rain showers possible across the area tonight through Tuesday. Minimal rainfall expected.

- Warmer on Tuesday with southerly gales to 35 knots expected over northern Lake Michigan and east central Lake Superior.

- Cooler temperatures return mid to late week with breezy northwest winds and additional chances for light lake effect rain showers, mainly in the east.

DISCUSSION

Issued at 305 PM EDT Mon Oct 5 2026

Water vapor imagery and RAP analysis reveal deep upper level troughing centered over Quebec this afternoon, with lingering cold air advection in northwest flow supporting some lake induced clouds and a few rain showers over the eastern half of the UP this afternoon. Meanwhile, surface high pressure is building in from the west, making for clear skies across the rest of the area with temperatures mainly in the 50s today. Showers will diminish through the rest of the afternoon into this evening as high pressure continues to move across the region.

Attention then quickly turns to another low dropping out of central Canada into Ontario on Tuesday. A weak warm air advection regime ahead of this system will bring the chance for some light overrunning precipitation across the UP tonight into Tuesday. Any rain that does manage to reach the ground will be limited to a trace to a few hundredths of an inch given weak forcing and dry antecedent conditions. Also can't rule out the potential for a few snowflakes to mix in overnight as some interior locations dip into the low to mid 30s. Look for showers to potentially increase in coverage later in the day across the east as better forcing arrives with the progression of the upper trough into Ontario. Temperatures will run as much as 10-15 degrees higher than today on Tuesday afternoon as southerly low level flow sends highs into the upper 60s in the north and the low 70s in the south. This will be accompanied by gusty south winds aided by a 40 kt low level jet, producing 15 to 25 mph winds gusts across much of the area and some 30+ mph gusts along the Lake Superior shoreline.

Cold air advection quickly returns Tuesday night into Wednesday in the wake of the system, kicking off another round of potential lake effect rain showers and breezy conditions during the middle to later portion of the week as temperatures return to seasonal norms in the 50s for Thursday and Friday. Surface ridging then favors drier and warmer weather into the weekend.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 822 PM EDT Mon Oct 5 2026

VFR will be the predominant flight category for the duration of the TAF period. However, will carry PROB30s at both IWD and SAW early tonight for lake induced rain showers that could result in periods of brief MVFR visibilities. Confidence remains too low, though, so will leave out MVFR mention for now. So, this leaves wind shifts and LLWS threat as main impacts this TAF period. Winds will initially start out northeasterly, gradually veering to the south and southwest through the course of the TAF period. An early morning low level jet will enhance LLWS, which is highlighted at all TAF sites by Tue 09-12Z.

MARINE

Issued at 305 PM EDT Mon Oct 5 2026

Lake Superior: Winds have diminished to 15 kt or less across the lake this afternoon as high pressure builds overhead and brings an end to northwest flow. However, don't expect these conditions to last very long as southerly winds increase to 20 to 30 kts across most of the lake by Tuesday morning. Have upgraded to a Gale Warning across parts of east-central Lake Superior with the afternoon forecast package as model soundings indicate an unstable layer that will help allow 35-40 kt winds at 925 mb mix down to the surface Tuesday morning into the afternoon. Winds weaken to around 20 kts by early Tuesday evening, picking back up to west to northwest winds of 20 to 30 kts by Wednesday morning as the cold sector of the low moves through the region; as of the time of this writing, the latest LREF has only a 10% chance for northwest gales up to 35 kts over the eastern lake on Wednesday. With additional CAA continuing into Thursday morning, we could see some lake effect rain showers that produce lightning from time to time over the eastern lake as well as strong/elevated winds up to 30 kts. However, once sfc high pressure ridging starts to return late this week, expect the winds to decrease with time on Thursday, eventually becoming 20 kts or less Thursday night and generally continuing that way through Friday.

Northern Green Bay and northwestern Lake Michigan: Northwest winds of 15 to 20 kts dwindles to around 15 kts or less late this afternoon as high pressure ridging moves overhead. However, don't expect the calmer winds to remain all that long as an incoming phased low over northern Ontario digs towards the Upper Great Lakes tonight through Tuesday. This will increase winds from the south and southwest, with a Gale Warning now in effect for the nearshore zones Tuesday afternoon into late Tuesday evening. Opted for a Small Craft Advisory within the Bay of Green Bay as winds should peak closer to 30 kt. That said, can't rule out some sporadic gusts to 35 kt in outer portions of the bay and towards Big Bay de Noc Tuesday afternoon. While winds look to decrease to 15 kts or less with time Tuesday evening, expect them to increase once again to 15 to 20 kts from the northwest on Wednesday within the cold sector of the phased low. With reinforcing CAA continuing into Thursday, expect the gustier winds to continue until high pressure ridging moving in late this week returns light winds of 15 kts or less back to the region late Thursday; expect the light winds to continue through Friday as well.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning from 9 AM to 3 PM EDT Tuesday for LSZ248>250-266.

Lake Michigan... Gale Warning from 2 PM to 8 PM EDT Tuesday for LMZ248-250.