textproduct: Marquette

KEY MESSAGES

- Widespread rain this evening into tonight. Rainfall amounts between 0.25 and 0.75 inches are likely by Tuesday afternoon, greatest amounts south-central and east. Amounts between 1 and 1.25" are possible in areas of more persistent showers and thunderstorms.

- Dual directional gales 35-40 kts are expected this afternoon through Tuesday.

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

DISCUSSION

Issued at 224 PM EDT Mon Apr 27 2026

Afternoon RAP analysis and GOES water vapor imagery highlight a broad mid level troughing pattern encompassing the western half of the CONUS/Canada. Another trough just off the New England coast pinches a ridge centered over the Lower Great Lakes. The primary focus of the short term is on the negatively tilted shortwave over NE and IA. This feature continues to pivot over WI and MI, sending the surface low from southeast MN this afternoon over western Upper MI tonight, reaching northern Ontario Tuesday morning. The PVA with this trough pivoting overhead alongside WAA and isentropic ascent are supporting a round of showers lifting toward the UP noted on the radar mosaic. Even though the wind field will provide sufficient wind shear, instability will only be on the end of a few hundred j/kg of MUCAPE, focused over the south-central and eastern UP (likely less than 1000 j/kg, mean HREF MUCAPE is only 100-500 j/kg). Not expecting any severe weather, but some gusty winds up to 40-45 mph are possible in heavy downpours late this afternoon and evening as this round of showers and storms lifts through. In regard to the rainfall amounts, PWATs do increase to between 1.00 to 1.25 inches with this wave, but the brevity of the event and severity/extent of storms leaves QPF on the lower side. Generally expecting 0.25 to 0.75 inches of rain by Tuesday morning, highest amounts south-central and east where the best forcing and instability align. That said, higher amounts up to 1.25 inches can't be ruled out where stronger storms occur or persist (15-25% chance).

Otherwise WAA keeps temps above normal in the 50s to mid 60s, warmest east today. Southeast winds will remain breezy through this evening, gusting 20-30 mph. Model soundings show isolated potential up to 40 mph at times. This warmer period lasts through tonight as temps only settle into the upper 30s to 40s, coldest west as a cold front begins moving through. Rain ends Tuesday morning in the wake of the cold front. Expect breezy west to northwest winds gusting to 25-35 mph (up to 40 mph in the Keweenaw) on Tuesday with CAA, a tight pressure gradient, and a strong isallobaric wind component. Temps will be closer to normal in the mid 40s to mid 50s; near 60 in southern Menominee County.

Once the UP is in the wake of the low, high pressure will ward off any meaningful precip until late this weekend. Meanwhile, the persisting troughing pattern aloft keeps cooler than normal temps going through the forecast with highs in the 40s to 50s and lows in the 20s to 30s. Fire weather will be the only potential for concerns, but uncertainty in wind strength and how efficient air will dry precludes any deviations from the NBM with this package.

River flooding: With the area of heavier rainfall likely occuring outside the current minor to moderate river flooding on the Michigamme River, no significant changes are expected. River flooding will be mitigated through the rest of the week by cooler temps limiting rapid snowmelt and mostly dry weather.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 707 PM EDT Mon Apr 27 2026

Conditions deteriorate tonight as -SHRA moves through the terminals, with IFR or lower conditions developing this evening. Some LLWS could be seen at IWD and CMX this evening, and is expected at SAW for the next few hours as the low pressure's center moves through the U.P. Once the low passes tonight, expect the winds to pick up from the west and for conditions to slowly improve through the early morning hours through Tuesday as the -SHRAs end and skies progressively clear out throughout the day. VFR conditions are expected to return across all of the terminals by late Tuesday afternoon.

MARINE

Issued at 346 PM EDT Mon Apr 27 2026

A low pressure approaching from the southwest has increased east to southeast winds across the lake to 15-30 kts with gales of 35-40 kts expected over the east into tonight, particularly along the international border. A few gusts up to 45 kts can't be ruled out at high observing platforms this evening, but better odds for those stronger winds are confined northeast of the international border. Expect significant wave heights to build up to 8 to 12 ft by tonight over the northeast. A few thunderstorms are possible this evening.

The next period of gales is expected behind the cold front Tuesday morning out of the west as the low moves to northern Ontario. Strongest winds once again will be over the eastern waters, but opted to hoist a Gale Warning for the zones just west of the Keweenaw as cold air advection combined with a tight pressure gradient and strong isallobaric wind component boost probabilities of low end gales to at least 60%. Significant wave heights of 8 to 14 ft are expected over the east on Tuesday with 4 to 8 ft over the west.

The rest of the forecast remains benign under the influence of high pressure. Winds mainly hold 20 kts or less.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning from 5 AM EDT /4 AM CDT/ to 2 PM EDT /1 PM CDT/ Tuesday for LSZ241>243-263.

Gale Warning until 5 PM EDT Tuesday for LSZ244-245-250-251-264- 265.

Gale Warning from 8 AM to 2 PM EDT Tuesday for LSZ246-247.

Gale Warning from 8 AM to 4 PM EDT Tuesday for LSZ248.

Gale Warning from 11 AM to 4 PM EDT Tuesday for LSZ249.

Gale Warning until 6 PM EDT Tuesday for LSZ266-267.

Lake Michigan... None.