textproduct: Marquette

KEY MESSAGES

- Isolated/scattered light lake effect rain/drizzle wraps up over the area today (mainly over the east). Expect no more than a trace of rainfall.

- Could see some light rain showers return across the area tonight through Tuesday.

- Southerly gales to 35 knots possible over NW Lake MI, northern Green Bay, and southeastern Lake Superior on Tuesday.

DISCUSSION

Issued at 206 AM EDT Mon Oct 5 2026

As another subtle shot of CAA brings light lake effect rain showers (with some lightning at times no less!) to the eastern U.P. early this morning, with satellite imagery showing mostly clear skies across most of the area as temperatures have dropped down into the 40s to even upper 30s at spots. While the lake effect cloud cover/showers over the east today will keep things warmer/more insulated before dawn, thinking we could see some of the cold spots in the interior west drop down to around 30 before sunrise this morning. With high pressure ridging moving overhead later today, expect the lake effect clouds/precip to wrap up across the eastern U.P later this morning, with no more than a trace of rainfall expected from it. With antecedent cooler air overhead, expect the highs today to only get into the 50s across Upper MI. Likewise, expect the winds to dwindle today via the incoming high pressure ridging moving overhead late in the day.

That being said, more active weather is expected to return tonight as a Clipper low phasing with another northern Canadian low digs towards the Upper Great Lakes late tonight through Tuesday. While most medium range QPF guidance keeps the area dry tonight, with the latest NAM and several CAMs now showing mainly rainfall moving in from west to east along a subtle shortwave passing by tonight into Tuesday, thinking we could see some light rain showers (that potentially even mix with or over to snow at times!) across the area tonight into Tuesday morning. However, capping the forecasted rain chances at 50% for tonight as antecedent dry air from the high pressure ridging just leaving the area will need to be overcome. Overall, not thinking the area will receive much rainfall, as even the latest REFS shows a 0% chance for over a tenth of an inch of rain. That being said, it may be enough to at least make the ground a little wet. As the phased low approaches from northern Ontario on Tuesday, we may see rain chances increase for the eastern U.P. throughout the day as synoptic support strengthens. In addition to the rain chances, expect winds to pick up from the south on Tuesday, particularly over the eastern half of the U.P. where south to southwest wind gusts of 25 to occasionally even 35 mph are possible by the afternoon hours. As the cold sector of the phased low moves in Tuesday night and reinforcing CAA continues even into Thursday morning, expect to see some light lake effect rain showers (with potentially some rumbles of thunder at times) over the eastern U.P. again; expect nothing more than a couple hundreths of an inch of precipitation with the lake effect rainfall though as delta-Ts will be in the lower teens. Yet, even despite the CAA rolling into the area, expect above normal temperatures to return to the U.P. for the mid-week as highs reach into the 60s to around 70 in the south central; it looks like it won't be until Thursday when 850mb temps are coolest when high temperatures return to normal (highs in the mid 50s to mid 60s).

While high pressure ridging moving in late this week is looking to bring dry weather back over us for at least Friday, an impressively deep Clipper (~995mb) lifts from the Rockies late this week and either splits into two separate lows or continues along the southern Canadian Prairies through the weekend. Regardless, this Clipper low is looking to be responsible for well above normal temperatures returning to the area this upcoming weekend, with highs into the 70s possible by next Sunday.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 125 AM EDT Mon Oct 5 2026

Other than some MVFR fog at IWD highlighted with a TEMPO early this morning, VFR will be the prevailing flight category for the TAF period. Lake effect rain showers/drizzle have become a bit more widespread over the last hour. So, will initially carry a VCSH mention at CMX, but most showers should stay east of the TAF sites and remain non impactful. Meanwhile, breezy northwest winds will persist this morning at CMX with gusts in excess of 30 kts through at least Mon 09Z.

MARINE

Issued at 206 AM EDT Mon Oct 5 2026

Lake Superior: Northwest winds of 20 to 30 kts with a few gale force gusts up to 35 kts still possible early this morning dwindle today as high pressure ridging moves overhead late. While some lightning is being seen with some of the lake effect rain showers over the eastern lake today, expect that too to die away by the late morning hours as the center of the ridging approaches. Light winds of 20 kts or less return by the afternoon hours as the high's center moves overhead. However, don't expect the weak winds to remain over Lake Superior all that long as southerly winds increase to 20 to 30 kts across most of the lake by Tuesday morning, with gales up to 35 kts possible over the eastern lake during the mid morning to early afternoon hours (30 to 60% chance of low-end gales according to the REFS); expect a Gale Watch to be forthcoming later this morning. As winds veer with time on Tuesday as a phased low approaches from northern Ontario, expect the winds to progressively weaken to around 20 kts by the early 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 gales up to 35 kts possible by the afternoon hours (40 to 80% chance according to the latest REFS run); a Gale Watch should be forthcoming in the next few hours early this morning. 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... None. Lake Michigan... None.