textproduct: Marquette

KEY MESSAGES

- Scattered showers and thunderstorms continue through the afternoon and evening; the best coverage is across the western and central UP.

- Temperatures remain below normal until the end of the work week.

- Above normal temperatures and increased humidity return early next week, along with periodic showers and thunderstorms.

DISCUSSION

Issued at 236 PM EDT Wed Jun 24 2026

Early afternoon water vapor imagery and RAP analysis feature midlevel troughing digging into eastern MN/NW WI, while at the surface, low pressure is centered roughly over NW WI. Ahead of this, rounds of scattered showers and storms have developed over the western half of the UP, though some drier air working northward from the WI border has cut back on coverage somewhat. Still, this has also resulted in more breaks of sunshine, aiding in surface destabilization in the wake of an otherwise cloudy, showery first half of the day. Additional showers and storms are already starting to pop off closer to the WI border in an environment with steepening low-level lapse rates and SBCAPE already near and even in excess of 1000j/kg. Still, shear remains limited at best and forcing diffuse, so organized severe convection is not expected. That said, storms throughout northern WI have already shown the potential for some hail and a stronger wind gust in the taller cells; we will thus need to monitor convection re-developing over the southwest and south- central UP the rest of the afternoon for similar threats.

Storms largely taper off over the western half of the UP this evening as our surface low continues to track towards Lake Michigan and into the LP. Lingering chances for showers will be limited to the eastern UP. Light winds and plenty of lower-level moisture where we picked up on rainfall today will contribute to a potential for fog development overnight, which may be dense at times. Otherwise, expect a quiet night with lows in the mid to upper 40s for most, and in the lower 50s near Lake Michigan. Thursday, the surface low continues to pull away into the St. Lawrence Seaway and ridging gradually builds in, keeping most of the UP dry. The exception will be the eastern UP, where some wraparound moisture in the vicinity of our exiting system and some lake breeze interactions may kick off a few more showers and rumbles of thunder during the afternoon. Friday turns dry with surface high pressure comfortably in place.

Temperatures remain below normal through the remainder of the work week, with highs ranging in the low to mid 70s (away from the Great Lakes) and lows in the 40s to lower 50s. A mid to upper level PacNW low moves into the northern Rockies this weekend, then eventually lifts into the Canadian Prairies early next week. As this happens, midlevel ridging builds over the Great Lakes and Ontario, with surface high pressure centered over the ON/QB line. This puts us in increasingly warm, moist lower-level SSW flow. Thus, expect above normal temperatures to finally return to Upper Michigan, with highs climbing into the 80s as early as Sunday and potentially the 90s into next week. With the upper-level pattern connecting us with the warm, moist air in the Gulf, expect rain showers and thunderstorms to return as shortwave lows lift through the area from time to time next week.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 143 PM EDT Wed Jun 24 2026

Low pressure will move through the Upper Great Lakes tonight and Thursday bringing shra/tsra this afternoon. This will result in MVFR conditions at times at all the TAF sites this afternoon. Showers may linger in the SAW vicinity tonight but the most impactful weather will be the development of fog as a onshore, upslope flow develops. This will result in IFR/LIFR late tonight into Thursday morning. Fog may become dense and could not rule out VLIFR (40% chance). Fog will begin to mix out mid-morning on Thursday. Overall winds will be light, turning northerly from west to east this afternoon into tonight.

MARINE

Issued at 236 PM EDT Wed Jun 24 2026

Low pressure moving into NW WI is keeping winds of of the E/NE this afternoon, with gusts increasing to around 20-25kts over the western and east-central portions of the lake. Showers are also moving out over the water, with some embedded thunder as well. As the low continues towards the St. Lawrence Seaway tonight into Thursday, rain chances taper off and winds to slacken to 20 kts or less once again. However, some marine fog could develop over the lake tonight and continue into Thursday; some of the marine fog could be dense in spots. Will keep an eye on the expected vis conditions tonight into Thursday in case a Marine Dense Fog needs to be issued in the future.

Lake Superior looks to remain fairly quiet the rest of this week into this weekend, until we see an upper-level pattern shift via a PacNW low moving into the Northern Rockies this weekend before lifting into the Canadian Prairies early next week. As that occurs, a shortwave rotating around the upper-level low into the Northern Plains/Upper Midwest could increase E winds over the lake to 20 to 30 kts by Sunday.

MQT WATCHES/WARNINGS/ADVISORIES

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