textproduct: Marquette

KEY MESSAGES

- Patchy dense fog is possible again tonight, mostly in the Keweenaw and near Lake Superior.

- Widespread rain chances return Monday night. Rainfall amounts between 0.25 and 0.75 inches are likely by Tuesday afternoon, greatest south-central. Amounts between 1 and 1.5" are possible in areas of more persistent showers and thunderstorms.

- Dual directional gales 35-40 kts are possible (50-80% chance) Monday afternoon through Tuesday.

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

DISCUSSION

Issued at 243 PM EDT Sun Apr 26 2026

Early afternoon GOES satellite imagery reveals mostly sunny skies across Upper Michigan save for areas of the far west where a stalled frontal boundary is lifting some light showers into the western arm of Lake Superior. Afternoon temps have pushed into the mid 50s to low 60s under the sun with some cooler 40s seen nearer the lakeshores. Quiet weather is expected overnight with patchy dense fog development possible mainly in the Keweenaw. Bufkit soundings out of CMX highlight this potential as light easterly winds advect in the marine layer under a sharp inversion, further aided by weak upsloping into the Spine. Otherwise, temps fall into the low 40s to upper 30s tonight.

Broad troughing across the western CONUS digs into the northern periphery of the sub-tropical jet tonight, sending a sharp shortwave and deepening surface low pressure into the Plains tomorrow morning that is slated to lift north into the Great Lakes by the afternoon. Ample moisture (PWATS between 1 and 1.25") and isentropic lift will be the impetus for widespread rainfall and a few embedded thunderstorms through early tuesday afternoon. There remains some uncertainty regarding the northward extent of elevated instability into the UP, but given the strong LLJ wouldn't be shocked to see some stronger showers and embedded storms work across the south-central. By Tuesday afternoon ensembles suggest a widespread 0.25-0.75" with pockets of 1-1.5" possible in the south-central where more persistent showers and thunderstorms are most likely. CAM ensembles (HREF/REFS) support this notion, highlighting a 40-60% chance for QPF >1" largely confined to Menominee/Delta counties. Higher QPF solutions have the potential to bring about area river rises and minor flooding. Precipitation ends from west to east through Tuesday behind the surface cold front, replaced by drier conditions and incoming high pressure.

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 /00Z TAFS THROUGH 00Z MONDAY/

Issued at 717 PM EDT Sun Apr 26 2026

Generally VFR conditions are expected to continue through tonight as marine FG from Lake Superior is now predicted to avoid CMX during the overnight hours (less than 20% chance of FG happening at CMX overnight now). As a shortwave low lifts from the Central Plains tonight into the Upper Midwest on Monday, expect lowering cigs and eventually rain showers to enter into the U.P., with the showers mainly starting across the area during the afternoon hours (save for maybe in the late morning at IWD). Ahead of the low arriving, expect marginal LLWS to develop over the TAF sites tonight, particularly at IWD where the LLWS chances are highest. With gusts picking up from the SE on Monday, the LLWS goes away during the daylight hours; however, LLWS could return across the terminals after the end of the TAF period as the shortwave low crosses over the U.P.

MARINE

Issued at 243 PM EDT Sun Apr 26 2026

High pressure extending overhead keeps winds light and variable through the rest of 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 40-60% 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 modest 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).

Opting to issue a Gale Watch across much of the eastern lake covering both periods of gales tomorrow afternoon through Tuesday afternoon.

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.