textproduct: Marquette

KEY MESSAGES

- Smoke from upstream wildfires will continue to impact Upper Michigan. Air Quality Alerts remain in effect through today. Consider limiting strenuous outdoor activity or remaining indoors when possible.

- A few showers and thunderstorms are possible over the western half of the UP tonight.

- Strong to severe thunderstorms capable of producing damaging winds and large hail are anticipated Monday PM. Those with outdoor plans should continue to monitor forecast updates.

DISCUSSION

Issued at 330 AM EDT Sun Jul 19 2026

Early morning GOES satellite imagery reveals mostly clear skies under sprawling surface high pressure stop the UP save for some patchy stratus/fog. Dense wildfire smoke and patchy fog is leading to localized visibility reductions as noted by area webcams and ASOS sensors. Mostly dry weather is expected today under the influence of high pressure, however, cant rule out some showers and thunderstorms reaching the lake and UP as midlevel ascent increases ahead of a deepening trough. SPC has introduced a General Thunder outlook for the UP with the far eastern edge of a Marginal Risk (level 1/5) nibbling onto the western lake and Ironwood. The main concern for this forecast period present's itself on Monday as a vigorous shortwave dives southeast from Canadian Prairies through the Upper Great Lakes. Warm air advection driven showers and thunderstorms will likely be occuring during the morning and afternoon hours Monday before a second round of storms sweeps the area along and ahead of the cold front during the evening to overnight hours of early Tuesday morning. CAM ensembles suggest airmass recovery will occur Monday afternoon, priming the environment for strong to severe storms capable of producing damaging winds and large hail. At this time, SPC has maintained a Slight Risk (level 2 of 5) for the entire UP and Lake Superior, and included an Enhanced Risk (level 3 of 5) extending from IA/WI upwards into the western and south-central UP. Those with outdoor plans need to monitor forecast trends as well as have a way to receive a warning when they are subsequently issued.

Expect cooler conditions on Tuesday into Wednesday behind the cold front that will sweep through the area Monday night. High temperatures will be mainly in the 70s with 60s possible close to Lake Superior. It will be breezy on Tuesday with north winds potentially gusting to 30 mph over the land areas and over 45 mph over the Great Lakes. Swim conditions will likely become dangerous on Tuesday for the Lake Superior beaches of Marquette and Alger County. Smoke could also increase again with the northerly flow.

Winds become southerly for Thursday through Saturday with highs in the upper 70s to low 80s as ridging builds into the central U.S. and into the western Great Lakes. There is a chance for showers and thunderstorms on Friday night as a shortwave rounds the northern periphery of the ridge.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 757 AM EDT Sun Jul 19 2026

Patchy dense fog/smoke is noted on satellite, area webcams, and METARs this morning, though some improvement to visibility has taken place since sunrise. Expecting fog to mix out through the early morning but not expecting a quick rise in visibility as dense wildfire smoke still remains locked in the region. High pressure will dominate today, providing mostly clear skies save for the surface smog. Gradual increase in S to SW winds and diurnal mixing should help improve vis to MVFR at all sites this afternoon. Some sneaky showers/thunderstorms may attempt to reach the far western UP and Keweenaw late tonight, so have opted to include prob30s at IWD and CMX for this scenario.

MARINE

Issued at 330 AM EDT Sun Jul 19 2026

Winds largely <15 kts are expected today under the influence of expansive surface high pressure. Southwest winds will increase on Monday to 15-25kt as a storm system approaches the lake. A few showers and thunderstorms are possible tonight in the western half. Some of the thunderstorms on Monday could be strong to severe with large hail and high winds. Smoke will continue to reduce visiblity though some improvement may occur with the stronger southerly flow pushing smoke back north.

A cold front will sweep across the lake Monday night with gusty northwest winds developing on Tuesday as low pressure deepens over Ontario. NBM continues to show likely gales (50-75% chance) over the eastern half of the lake on Tuesday. The Euro ens has come into better agreement over the last 24 hours, now highlighting a 50-70% chance for isolated gales east of the Keweenaw Peninsula. Given the strong pressure rises of 6-7 mb/6hr and modest cold air advection for this time of year, the stronger winds seem plausible. Continue to monitor the forecast over the next few days as details become clearer.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Dense Smoke Advisory until 8 AM EDT /7 AM CDT/ Monday for LSZ240>251-263>267.

Lake Michigan... Dense Smoke Advisory until 8 AM EDT Monday for LMZ221-248-250.