textproduct: Marquette

KEY MESSAGES

- A Beach Hazard Statement is in effect today for the shoreline of Alger County due to strong winds and high waves creating dangerous rip currents and swimming conditions.

- Fog is possible across much of the central and eastern U.P. tonight.

- The next chances for widespread showers and thunderstorms arrives in the west on Tuesday, spreading east overnight and Wednesday before ending for most late Wednesday.

- Generally seasonable temperatures are expected through the rest of this week.

DISCUSSION

Issued at 221 AM EDT Mon Aug 24 2026

With clear skies overhead this morning, observation stations are already showing temperatures dropping into the 40s and even mid to upper 30s across the western half of the U.P., with the Baraga Plains RAWS site already down to 37F as of 1 AM EDT. Should this trend hold, there could be multiple spots in the western interior U.P. that see lows bottom out in the mid to potentially even lower 30s, allowing patchy frost to form (particularly elevated sfcs). In addition, there could be some patchy fog over the far west as warm air advection aloft moves overhead, but confidence on fog occurrence is still somewhat low even now given the lack of it being seen upstream in northern WI and MN on satellite. After the sun rises today, expect fairly calm and quiet weather as high pressure ridging moves overhead. While we should be warmer than we were yesterday, with antecedent cooler air taking time to move out of the area, thinking highs will generally stay within the 70s. Gusty NW winds over Lake Superior will keep dangerous waves and rip currents over the beaches of Alger County today, so another Beach Hazard Statement is in effect throughout the entirety of today over there. The swimming conditions along the Marquette County shoreline are better today due to the shore's geometry protecting it somewhat from NW'rly winds. Nevertheless, some rip currents and hazardous waves are still expected along the beaches of Marquette County, so swimmers should still exercise caution and not get into the water unless they are experienced swimmers as the rip currents and waves could still tire out people fast.

Moving into tonight, expect the generally quiet weather to continue as clouds build in from the west with time via an approaching Clipper low. Given the continuing WAA, lows tonight are expected to not be as cool as they are this morning; that being said, some of the coldest spots in the interior central and east could drop down into the mid to upper 30s thanks to mostly clear skies for the overnight hours. In addition, with WAA continuing in the lower to mid-levels of the atmosphere, some fog is possible over mainly the interior central and east tonight as temperatures cool to around the dewpoint. Should the fog form, we could see visibilities of 1/2 mile or less, which could create traveling/visibility concerns for the morning commute for those going to work and/or school.

Our next shot of rainfall looks to arrive over the western U.P. on Tuesday as the Clipper approaches. While global/medium range guidance is more reserved on the start time of the rainfall, some of the CAMs do show showers starting as early as the mid-to-late morning hours over the far west given the modest isentropic lift moving into the area. That being said, with not much diurnal instability to work with, I have my doubts as to rain chances starting that early. Therefore, have the precipitation chances capped at around 30% between 8 AM and 2 PM EDT over the west half on Tuesday. As better diurnal instability develops over the area and a LLJ develops and brings some support by the afternoon hours, shower and thunderstorm chances increase over the west half. While the best shearing and helicity are projected to be south of us in northern WI, thinking it may not be totally out of the realm of possibility for a stronger (but sub-severe) thunderstorm or two to occur. As the showers and storms continue and spread into the rest of the U.P. Tuesday night and Wednesday, expect the rainfall chances to become maximized to ~80 to 90% as the low's center moves through Lake Superior. The additional forcing from the low with PWATS 1.25 to 1.50 inches could bring heavy rainfall at times, although QPF guidance is fairly muted for the most part on rain totals with this event. Therefore, while it does seem like most, if not all, of the U.P. will see at least some rainfall, given the convective nature of the precipitation not everyone will see similar amounts; as of now, the NBM currently has a 50 to 99% of a quarter inch of rainfall occurring between Tuesday morning and Thursday morning, with the greatest chances over the east and interior west whereas the lowest chances are in the south central. The rainfall chances look to generally end over the area by late Wednesday as the Clipper lifts northeast towards James Bay. However, some CAA behind the low could kick-off some light lake effect rain showers over the area on Thursday, but accumulations would be very small as high pressure builds in from the west once more.

High pressure ridging returns to the U.P. once again by Friday, allowing for dry weather to return to the area. Moving into this upcoming weekend there really isn't a good signal for the precipitation chances as some upper level ridging continues to build into the area, even as troughing starts to move back in at the sfc late this upcoming weekend. Nevertheless, expect the seasonable temperatures to continue on from this week on into next week as medium range guidance hints at a somewhat more active pattern continuing into early September.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 651 AM EDT Mon Aug 24 2026

VFR conditions continue today and are expected to continue through tonight as high pressure moves overhead. While winds could be gusty over SAW, expect them to dwindle by the mid-afternoon hours and onwards. Tonight, we could see some FG at the terminals. However, with FG chances at 20% or less currently over the terminals, decided to not include it in the TAFs at this time.

MARINE

Issued at 221 AM EDT Mon Aug 24 2026

Northwest winds of 20 to 30 knots over Lake Superior and 20 to 25 knots over northern Green Bay and northwest Lake MI slowly dwindle to 15 knots or less by this evening as the center of high pressure ridging finally arrives over the area. However, as a Clipper low approaches Lake Superior on Tuesday, expect winds to pick up from the south over Lake MI, Green Bay, and eastern Lake Superior, with gusts of 20 to 30 knots being seen by Tuesday evening. In addition to the winds, showers and storms begin moving over western Lake Superior on Tuesday, continuing through the rest of the Upper Great Lakes Tuesday night through Wednesday before generally wrapping-up late Wednesday as the Clipper lifts towards James Bay. As this occurs, expect the winds to slowly become westerly, first over Lake Superior Wednesday morning before shifting westward over northern Green Bay and northwest Lake MI by Wednesday evening. As this occurs, expect the winds to die-down to 15 knots or less over northern Green Bay and northwestern Lake MI, whereas westerly winds of 20 to 25 knots continue over Lake Superior. CAA behind the Clipper is expected to veer the winds to the northwest, keeping the 20 to 25 knot winds over at least the eastern half of Lake Superior on Thursday as northwest winds of 15 to 20 knots develop over northern Green Bay and northwestern Lake MI. As high pressure builds in from the west late this week, expect the winds to die-down to 15 knots or less again by Thursday evening and to remain light into at least this upcoming weekend if not potentially longer.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Beach Hazards Statement through this evening for MIZ006.

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