textproduct: Marquette

KEY MESSAGES

- Scattered showers (30-60% chance) and isolated thunderstorms (20% chance) move west to east across the UP on Tuesday. Strong to severe storms are not expected and rainfall amounts will be limited.

- Wind gusts near 25 kt will result in hazardous conditions to small craft along the western shore of the Keweenaw to the WI border late tonight into Tuesday, as well as for the nearshore zones of Lake Michigan Tuesday afternoon and evening. There is a high risk of rip currents for the Schoolcraft County beaches Tuesday.

- Above-average minimum temperatures tonight give way to seasonably warm temperatures through Wednesday evening before returning to above-average temperatures on Thursday.

DISCUSSION

Issued at 154 PM EDT Mon Aug 3 2026

Early afternoon water vapor imagery and RAP analysis show midlevel ridging extending from the central Rockies NEwd into the upper Great Lakes. Meanwhile an anomalous low is centered over northern Manitoba. A couple of notable shortwave troughs are orbiting this low, one of which is generating an area of rainfall over northern MN into southwestern ON, and another is in eastern Montana. The ridging will continue to promote dry conditions over the local area into tonight, although high clouds will increase.

Both of the aforementioned shortwave troughs will track NEwd, with their associated forcing passing north of the forecast area. Broad troughing/weak height falls will expand across the UP late tonight into tomorrow, with an associated frontal boundary passing through from west to east. Area of showers and a few embedded storms associated with midlevel theta-e advection will likely reach the far western UP around daybreak Tuesday, with coverage waning with eastward extend. MUCAPE generally stays below 500 J/kg, so any storms are not expected to be strong/severe. Best chance for surface- based destabilization will occur over the eastern half during the late afternoon into the evening Tuesday, but SBCAPE is forecast to remain below 750 J/kg, so severe weather is not expected. Some question whether surface based instability can even develop given model soundings depicting a warm nose around 800-850 mb, so coverage of storms is expected to remain isolated at best. Highs range from the low 70s west, where FROPA happens earliest, to low 80s east.

Weak ridging builds in the wake of the front for Wednesday, setting up a dry and seasonable day with highs mainly in the 70s. Another shortwave trough rotates through Thursday, but with a lack of any notable moisture, another dry day is expected. Temperatures are expected to be on a general warming trend late week into the weekend as low-level southwesterly flow develops. Thunderstorm potential enters the picture again by the weekend as strong quasi-zonal flow develops between Hudson Bay low and Four Corners high. Unclear whether the reservoir of greater instability will get this far north.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1256 PM EDT Mon Aug 3 2026

VFR conditions look to prevail the rest of this afternoon into this evening as high pressure ridging gives way to a cold front making its way eastward towards Upper Michigan, eventually arriving Tuesday morning. While some -SHRA could be seen over mainly the IWD and CMX during the morning hours, we could see -SHRA by SAW by around 18z tomorrow (~20% chance as of the current forecast), with higher chances of convection being seen after 18z. While the cold front is passing through, don't be surprised to see cigs drop down to MVFR over the terminals (mainly CMX and IWD Tuesday morning). In addition, with the front approaching tonight, expect LLWS to move over the terminals late tonight until gustier winds make it to the sfc Tuesday morning. Winds remain generally S'rly this afternoon, before becoming SW to W'rly by early Tuesday afternoon.

MARINE

Issued at 154 PM EDT Mon Aug 3 2026

Southerly winds increase tonight to 20-25 kt ahead of an approaching front. These conditions will be hazardous to small crafts, and Small Craft Advisories will likely be needed for the west shore of the Keweenaw to the WI border. There is a 20% chance of thunderstorms for the west half late tonight into Tuesday morning, and for the east half late Tuesday morning into the evening. Winds shift westerly behind the front Tuesday and gradually decrease, remaining near or below 20 kt for the rest of the week.

MQT WATCHES/WARNINGS/ADVISORIES

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