textproduct: Marquette

KEY MESSAGES

- Southwest winds gusting as high as 35 mph will diminish this evening.

- Southwesterly gales over western Lake Superior will diminish by early evening and late tonight over northern Lake Michigan.

- Dry weather expected through much of the workweek.

DISCUSSION

Issued at 106 PM EDT Sun Oct 18 2026

Early this afternoon upper air model height analysis and satellite water vapor imagery showed zonal flow across the northern tier of the United States with multiple closed lows north of the jet. At the surface the Upper Great Lakes was between high pressure over the eastern seaboard and a strong surface low moving through Ontario, with the U.P. sitting in the warm sector of the system. Little in the way of moisture was available though as warm, dry air in the low levels was advecting east from the central Rockies into the Midwest under strong west-southwest flow. Thus little in the way of clouds cover and moisture was accompanying the system's warm sector as it moves north of the area. The dry, warm low level air combined with gusty winds being mixed to the surface was bringing slightly elevated fire weather conditions to much of the U.P. Afternoon temperatures were unseasonably warm, in the low to mid 60s. This is about 10 degrees above average.

Tonight the low pressure over Ontario will track north and east of the area dragging a weak cold front south across the U.P. This will help settle the winds down as high pressure builds overhead through Monday. Thereafter, high pressure will dominate the weather pattern this week with light winds, warm afternoons (60s, 10-15 degrees above average), and cool nights with lows in the 30s for inland locations. Humidity will continue to run on the lower side the next few days but elevated fire weather conditions will be mitigated by light winds and good humidity recoveries overnight. The next chance for rain will come late next weekend as a stronger cold front sweeps across the area but overall trends are for a relatively dry frontal passage with just a chance for showers next weekend.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 106 PM EDT Sun Oct 18 2026

VFR conditions hold across the terminals as high pressure ridging remains for the next several days. Some LLWS may be seen for a couple of hours this evening at SAW, but with the LLJ moving away from the area this evening and tonight, expect the winds to become rather calm over all of the terminals late tonight/early Monday morning. Expect lake-induced winds by Monday afternoon, with potentially a slight northeasterly component across the area.

MARINE

Issued at 106 PM EDT Sun Oct 18 2026

Lake Superior: A cold front will drop South across the lake this evening and overnight bringing an end to the gales, with westerly winds dropping to around 30kt for the early evening hours and then below 20kt by midnight. Thereafter high pressure will dominate the forecast through the week. Expect light easterly flow, less than 15kt, through Monday night. A weak low pressure tracking through northern Manitoba and Ontario on Tuesday will bring southerly winds back to the lake, increasing to around 20kt. High pressure than builds back in for Wednesday night and Thursday with easterly flow of 15kt or less returning. A stronger cold front will approach the region next weekend with the potential for stronger southerly winds, through gale probabilities from the EPS remain very low (<10%) at this time.

Northern Green Bay and northwestern Lake Michigan: Southwesterly gales will come to an end late toinght as a cold front pushes through the area and high pressure building in behind it relaxes the pressure gradient. Thereafter expect light winds, mainly less than 10kt, through the remainder of the week as high pressure dominates the forecast. Southerly winds will increase on Saturday ahead of an approaching cold front.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Wind Advisory until 2 PM EDT this afternoon for MIZ005.

Lake Superior... Gale Warning until 2 PM EDT /1 PM CDT/ this afternoon for LSZ162-245>249-265.

Gale Warning until 5 PM EDT this afternoon for LSZ243-244-263- 264.

Lake Michigan... Gale Warning until 11 PM EDT this evening for LMZ248-250.