textproduct: Marquette

KEY MESSAGES

- Strong to severe storms are possible again today. However, there still remains some uncertainty on whether the severe convection will happen or not, and if so, where and when.

- Generally quieter weather in store after today into the middle of the week.

DISCUSSION

Issued at 227 AM EDT Mon Jul 27 2026

For the most part, yesterday into early this morning has turned into part 2 of a severe weather bust as supercell convection as skirted around the CWA to the west/southwest and east, mainly avoiding the western and central U.P. over the past 24 hours. That being said, synoptic-scale severe weather ingredients still for the most part remain in place as MUCAPEs of greater than 1000 J/kg either remain across the area or are replenished back up to that amount by the afternoon hours (if we receive convection overhead this morning). Meanwhile, bulk shear values still look to range from 30 to 65 knots, with an incoming Clipper low providing a forcing mechanism. While guidance has somewhat converged on a solution bringing at least some showers and storms to the area today, I remain HIGHLY SKEPTICAL on the severe weather threat considering 1) the past two days have been severe weather busts, either missing us to the west/southwest or east and 2) the latest WOFS runs show most of the resolved updraft helicities > 70 m2/s2 missing our area entirely to our south and west. After having a call with SPC this morning, it still seems probable that the far west could be grazed by some potentially severe convection; therefore a Severe Thunderstorm Watch is in effect until 14z this morning (or until cancelled) for Gogebic and Ontonagon counties. While the conditions for an isolated tornado no longer seem to be there, there is still a theoretical non-zero chance for some damaging hail and winds today. While showers and storms are possible throughout the entirety of today, the best chances appear to occur during the late afternoon hours as shown by the NBM wanting to bring likely (55-74%) to definite (75+%) chances of precipitation overhead during that time. As we approach the evening hours, expect the convection as well as the severe weather threat to vanish as the Clipper pulls the showers and storms further southeast into Lower Michigan.

Expect quieter weather as we move into the rest of the week as heights rise over the central CONUS, creating a quasi omega block pattern. While cold air advection moving in tonight could create some very light upslope drizzle showers in the north wind belts, thinking that we will remain dry due to sfc to mid-level ridging increasing over the Upper Great Lakes. Thus, while we should see temperatures closer to normal today and Tuesday, as the shortwave ridge begins to depart on Wednesday, expect temperatures to climb to above normal once again as we head towards the latter half of the week. In addition, with the departure of the shortwave ridge, we could see Northern Rockies/Canadian shortwaves move into the Upper Midwest near the end of this week into this weekend, allowing additional showers and storms to return.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 719 AM EDT Mon Jul 27 2026

Showers and storms are possible over the area today, potentially over IWD (25% or less) this morning, CMX until the mid-afternoon, and SAW until late this afternoon. Some of the storms could be severe, bringing damaging and erratic winds to the sfc as well as large hail; IWD this morning and SAW this afternoon have the best severe weather chances. In addition, IWD and SAW could see some MVFR to potentially IFR or lower conditions behind the convection today as N'rly winds pickup and marine FG moves onshore; while not expected, conditions down to airport mins could be seen tonight behind the convection over these terminals (10-20% chance).

MARINE

Issued at 227 AM EDT Mon Jul 27 2026

Light winds of 20 knots or less dominate the lake this week, although some gusts to 20+ knots are possible today as cold air advection follows behind a Clipper passing through the area. This Clipper could also bring showers and storms to the lake, with some potentially bringing damaging/erratic winds and large hail to the sfc. Expect the showers and storms to be done before sunset though as the convection moves off towards the Lower Peninsula.

Outside of the storms today, expect marine fog across much of Lake Superior, with much of it being dense. Therefore, a Dense Fog Advisory has been issued until Noon EDT. Fog could persist throughout the day today and restrengthen tonight, but the cold air advecting into the area from the north may hinder those efforts.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Dense Fog Advisory until 9 AM EDT this morning for MIZ007-014- 085.

Lake Superior... Dense Fog Advisory until noon EDT /11 AM CDT/ today for LSZ162- 263-264-266-267.

Lake Michigan... None.