textproduct: Marquette

KEY MESSAGES

- Dry weather expected through much of the workweek.

- Overall warmer than normal temperatures persist through the end of October. However, a period of cooler weather is possible early next week.

DISCUSSION

Issued at 307 PM EDT Tue Oct 20 2026

This afternoon sunshine was abundant across the U.P. with visible satellite imagery showing clear skies over a large expanse of the northern U.S. including the Great Lakes region. Water vapor imagery and model height analysis continued to show mainly zonal flow over the northern tier of the U.S. along with an upper low that had cut off from the flow digging down the Pacific Coast of the U.S. With abundant dry air and clear skies it was a chilly start to the day across the U.P. with temperatures in the 20s and 30s. However, temperatures had recovered nicely with most locations in the lower 60s early this afternoon under light southerly winds.

Through the remainder of the week the upper low pressure off the California coast will lift northeast through the intermountain west and into Saskatchewan, phasing with the upper level jet. This will amplify the flow downstream with ridging strengthening over the Upper Great Lakes. This will help continue our streak of warm afternoon highs some 10-20F above normal. With the dry air in place nights will continue to be chilly, dropping into the 30s until late in the week and weekend, as strengthening southerly winds help to keep temperatures in the 40s overnight.

A surface low pressure tracking well north of the area will keep southerly winds in place through tonight. This, combined with strong radiational cooling and winds off of Lake Michigan will bring patchy fog to the south-central and eastern U.P. tonight. Winds slowly turn back to the north and east on Wednesday afternoon and evening as another high pressure settles over the area. Low level moisture and a strengthening subsidence inversion could result in widespread fog and low clouds developing late Wednesday night and lingering into much of the morning hours, before lifting in the afternoon with diurnal heating and returning southerly flow.

As low pressure tracks north of the area this weekend southerly flow will strengthen resulting in breezy conditions Saturday, followed by breezy westerly winds behind the cold front Sunday. While the air isn't much colder behind the initial front it will be notably drier which could result in borderline elevated fire weather conditions on Sunday. While showers will accompany the front they are expected to remain rather hit-and-miss and appreciable rainfall is not expected.

Early next week ensembles are trending towards a period of cooler weather that could lead to at least some lake effect precipitation and high temperatures closer to or below seasonal averages. The NBM has a 40-75% chance for much of the U.P. to remain below 50F on Monday and Tuesday.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 724 PM EDT Tue Oct 20 2026

VFR conditions prevail tonight through Wednesday. Patchy dense fog may sneak into portions of the south-central UP with no expected impacts to any current TAF sites. A weak, dry cold front skirts across the UP tomorrow afternoon, turning surface winds to the NW while staying less than 15 kts.

MARINE

Issued at 307 PM EDT Tue Oct 20 2026

High pressure will dominate the forecast through Friday with winds mainly below 20 kts on both Lake Superior and northern Lake Michigan. An exception to this is south winds becoming southwest and gusting up to 25 kts tonight ahead of a cold front on Lake Superior, mainly along and east of the Keweenaw. A stronger low pressure tracking to the north of Lake Superior this weekend and an associated cold front will bring back a longer period of southerly 20-30 kt winds late Friday through Saturday, veering west for Sunday in the wake of the cold front. Gale probabilities remain low (~20- 40% chance on Lake Superior and less than 10% on Lake Michigan).

MQT WATCHES/WARNINGS/ADVISORIES

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