textproduct: Marquette

KEY MESSAGES

- Showers and storms re-develop along the cold front over the central UP this afternoon, then move eastward into the evening. Additional rainfall totals are expected to be 0.1" or less, though higher amounts are possible in storms.

- Additional scattered showers and thunderstorms are possible across mainly central and eastern portions of the UP tomorrow, but rainfall totals will remain minimal.

DISCUSSION

Issued at 346 AM EDT Fri Aug 21 2026

Today, the surface low off to our west tracks through the UP (perhaps opening up into a surface trough). This brings a cold front through the area, which looks to be draped somewhere across the central UP by mid-morning. Destabilization ahead of the front over the central and eastern UP will allow showers and storms to redevelop into the afternoon, but with very limited shear and MUCAPE below 1000j/kg, strong to severe storms are not expected. This should not be a washout, again with most areas receiving additional rainfall totals of a tenth of an inch or less. However, ensembles show as much as a 50% chance for higher embedded totals in excess of a quarter-inch in heavier downpours. Today is looking otherwise breezy ahead of the front, with southerly wind gusts to around 20 mph over the eastern UP. Temperatures peak in the lower to mid 70s behind the front, and the mid to upper 70s ahead of it.

Additional chances for showers and storms return for tomorrow as a midlevel low drops into northern Ontario, sending additional shortwaves and a shot of cold air advection into the Great Lakes. That said, the main story will be marine hazards and gusty northerly winds tomorrow/Sunday. Modest pressure rises coupled with cold air advection (850 mb temps between 3-6C Sunday) will create northerly gusts 20-30 kts with a 40-50% chance of gales to 35 kts over the eastern portions of the lake.

Model discrepancies follow into next week, though Sunday and Monday looks mainly dry, followed by on and off rain chances the rest of the forecast period as a series of shortwaves drop through the Great Lakes.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 742 AM EDT Fri Aug 21 2026

As low pressure moves into the area, VFR conditions will deteriorate to MVFR and potentially as low as LIFR with any showers and storms. VLIFR cigs are already being reported at CMX in the warm sector of the system. And, IWD and SAW are expected to follow with MVFR/IFR conditions as well by mid morning. As cooler air rushes into the terminals late this afternoon, expect to see a return to VFR conditions before sunset this evening. That being said, some FG could be seen over SAW late tonight as another weak low moves into the region. In addition, look for a wind shift through the course of the day from southerly to northwesterly with cold front passage. But, wind speeds will stay in the 5 to 10 kt range.

MARINE

Issued at 304 PM EDT Thu Aug 20 2026

Lake Superior - ESE wind gusts pick up to around 20kts over the east- central portions of the lake tonight, then gusts fall back below 20kts Friday afternoon while a passing cold front causes winds to shift over to the NW. The main marine hazards return Saturday and Sunday as a pair of systems bring modest pressure rises and cold air advection over the Lake resulting in gusty N to NW winds upwards of 20-30 kts beginning Saturday morning through Sunday night. At this time, there is a low chance (30-50%) for a few gales to 35 kts mainly between Marquette and Whitefish Point. Winds fall back below 20kts Sunday night, and stay mainly below 20kts through early next week.

Northern Bay of Green Bay and northern Lake Michigan - Southerly wind gusts up to 15-20kts will be possible over the Bay beginning later this evening, but become more common over the Bay and northern Lake Michigan late tonight and linger through Friday as low pressure traverses the area. This results in waves building between 1-3 ft (greatest in the open waters closer to Lake Michigan). A brief reprieve in winds comes Friday night behind a weak cold front, however, two systems then dive into the area Saturday and Sunday, resulting in gusty north to northwest winds 15-25 kts through Sunday night. Wind gusts briefly fall back below 20kts for Monday before potentially increasing again into the midweek period.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Beach Hazards Statement through this evening for MIZ014.

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