textproduct: Marquette

KEY MESSAGES

- Patchy dense fog is possible (30-60% chance) this morning.

- Widespread rain chances return Monday night. Rainfall amounts between 0.25 and 0.75 inches are likely by Tuesday afternoon.

- Mostly dry and cooler weather the remainder of next week.

UPDATE

Issued at 218 AM EDT Sun Apr 26 2026

Going forecast remains on track with GOES-East Nighttime Microphysics RGB imagery showing deep cloud cover in the west associated with a near-stationary boundary draped from western Lake Superior southwest to the Plains. Meanwhile, low cloud cover is building over the eastern UP and patches are developing in the central to western UP as well, and these low clouds can have dense fog associated with them, as the ERY METAR is showing M1/4SM FG VV000 at 115AM local time. While there is a slight chance (~20%) of a few showers with the stationary boundary in the west, the fog concerns will be of more impact in the near term. Should webcam and METAR evidence arise that the low stratus layer is indeed most or all dense fog, a Dense Fog Advisory may be needed for the Sunday commute, however, 00Z HREF guidance suggests only around a 40% chance of widespread fog formation, so no headline yet, but will watch observations closely this morning.

Otherwise, little change is needed to the going forecast. Probabilities and location of gales over Lake Superior are largely unchanged, even as that time range becomes covered by hi-res model output. While the new Day 2 SPC outlook puts the Marginal Risk of severe weather closer to the state line, the UP remains only in General Thunderstorm risk. Little to no change in the QPF forecast as well, and any other forecast element is too low of impact to deviate from the NBM.

DISCUSSION

Issued at 255 PM EDT Sat Apr 25 2026 Amended at 218 AM EDT Sun Apr 26 2026

Fairly quiet and benign weather persists over the weekend as high pressure ridging extends into the Great Lakes from Quebec. Aloft, a closed low spins over the Canadian Prairie, sending shortwaves along it's southeast periphery over the Dakotas and MN. This coincides with a frontal boundary which won't make much eastward progression this weekend. The combination yields a low chance (20% chance or less) for light showers grazing the western UP today. Otherwise patchy fog is possible into this morning (30-60% chance for vis below 1/4 mile) where there is weak upslope flow, particularly in the Keweenaw, north-central, and eastern UP. Temps settle into the 30s to low 40s this morning. Increasing southerly flow makes today's highs warmer in the 50s at the lakeshores and 60s in the interior. Slightly warmer lows tonight in the upper 30s to mid 40s.

Meanwhile a trough over the west coast moves to the Rockies today and out over the Plains on Monday. There is good model agreement this will develop a CO low late today, which will move out over KS by Monday morning and lift up to WI by Monday night. This is expected to bring the only substantial precipitation in the forecast to the UP Monday night into Tuesday as it moves overhead. Current NBM system total QPF is between 0.25 and 0.75 inches with 45-55% chances for >0.5 inches of rain across much of the CWA. Higher probabilities of >0.5 inches (up to 80%) reside in the south-central UP with lower values (~30%) noted in the far east. Probabilities of exceeding 1 inch are between 10-20% over the west half of the UP with higher values between 25-45% in the south-central UP. This has the potential to result in additional river rises, prolonging river flooding impacts. but not much if any areal flooding is anticipated as instability is not impressive limiting strong thunderstorm potential.

Surface high pressure once again becomes the dominating factor the remainder of the work week and possibly into the weekend, favoring drier weather. Mid level troughing becomes situated over Eastern Canada and the Midwest/Northeast, resulting in a cooler pattern with highs and lows between 5 and 10 degrees below normal; highs in the 40s to mid 50s and lows in the upper 20s to 30s. Medium range guidance struggles to resolve the mid level pattern into the weekend, thus confidence in any future precip chances remains low. That said, the troughing pattern and cooler northerly flow likely persists into May, captured well by the CPC outlooks out to 3-4 weeks showing below normal temps favored in each outlook.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 1253 PM EDT Sun Apr 26 2026

CMX and IWD are returning to VFR this afternoon, though MVFR/IFR ceilings may hang on at SAW for a couple more hours before skies largely clear out there for the rest of the day. For tonight, VFR is expected to persist at IWD and SAW, but fog and low stratus returns to CMX closer to midnight as low clouds over central Lake Superior move onshore. This brings a return to IFR overnight. An improvement to MVFR/VFR is expected there into Monday morning. Otherwise, look for winds to begin to increase at all terminals by mid-morning while rain showers move into the UP, first at IWD before the end of the forecast period.

MARINE

Issued at 255 PM EDT Sat Apr 25 2026

High pressure extending overhead keeps winds light and variable through the weekend. Easterly winds increase on Monday to 20-30 kts as low pressure moves to Wisconsin. There are two potential periods of gales as this low moves northeast over Lake Superior. The first period is southeast gales late Monday into Tuesday morning over the east, particularly near the international border waters. Probabilities for gales of at least 35 kts are generally 30-60% over the eastern open water zones, except up to 80% along the international line. How far southwest from the international line the first gales will occur depends on the low pressure track impacting the strength of the low level stability over the water. The second period comes behind a cold front with strong cold air advection and pressure rises yielding westerly gales on Tuesday, strongest winds over the east half of the lake (30-60% chance of gales to at least 35 kts).

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Watch from Monday afternoon through Tuesday afternoon for LSZ244-245-248-251-265>267.

Lake Michigan... None.