textproduct: Marquette

KEY MESSAGES

- Scattered shower and thunderstorm activity diminishes tonight.

- Gusty northwest winds will create hazardous beach conditions on Lake Superior tonight through Thursday.

- Seasonable temperatures persist the rest of this week before becoming seasonably warm this weekend into early next week.

DISCUSSION

Issued at 336 PM EDT Wed Aug 26 2026

Early afternoon GOES water vapor imagery reveals vertically stacked low spinning over eastern Lake Superior. Differential vorticity advection combined with meager surface based instability has been the driver of scattered shower and thunderstorm activity this afternoon, with the greatest concentration of thunderstorms (non- severe) in the east half from ISQ to Whitefish Point. Expecting this activity to persist this afternoon before diminishing altogether as diurnal instability wanes tonight and the upper-low moves into southern Ontario. Some lingering upslope light rain and or drizzle may be present tonight in the west half NW orographic lift areas. Otherwise, temps fall into the 50s tonight. Northwest flow aloft and building surface high pressure will usher in a cooler and drier day tomorrow as the Great Lakes become sandwiched between a descending trough near James Bay and a building ridge in the High Plains. Under breezy N to NW winds, temps in the upper 60s will be common across the north half while the southern UP peaks into the low 70s. Under mostly clear skies and calming winds tomorrow night into Friday morning, efficient radiational cooling may be able to produce low temperatures in the 40s to upper 30s for areas of the interior UP. Have opted to bide on the cool side of guidance (NBM 10th percentile) for this forecast package.

Height rises and W to SW mid-level flow brings seasonably warm temperatures and additional shortwave activity in the Saturday/Sunday timeframe to early parts of next week. No one day looks like a guarantee wash-out, but chances for showers and thunderstorms can be expected.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 206 PM EDT Wed Aug 26 2026

VFR cigs and visibilities are expected for KIWD and KCMX through Thursday morning, with ceilings rising as the cloud cover from the Clipper low leaves the area. SAW is expected to remain mostly under MVFR cigs, lowering to IFR Thursday morning as another shortwave trough drops south over the central U.P. KCMX could also see brief periods of MVFR cigs with this wave, however, current probabilistic guidance is not high enough (20-40% chance) at this time to include this change in the 18z TAF. Winds at all sites are expected to remain around 5-10kts, shifting from westerly to north-northwesterly overnight.

MARINE

Issued at 336 PM EDT Wed Aug 26 2026

Lake Superior: N to NW winds 20-25 kts with isolated gusts between 25-30 kts tonight through Thursday afternoon with waves 3-6 feet common between Marquette to Whitefish Point. Winds calm below 15 kts lakewide Thursday night through first half of the weekend.

Northern Lake Superior and northwestern Lake Michigan: N to NW winds 15-20 kts with isolated gusts to 25 kts and waves 1.5-3 ft, greatest in the open waters. Winds become less than 10 kts late into Friday morning.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Beach Hazards Statement until 8 PM EDT this evening for MIZ014.

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