textproduct: Marquette

KEY MESSAGES

- The threat for flooding continues, but will decrease through this weekend as cooler weather moves in, slowing snowmelt.

- West to northwest gales up to 40 knots are expected over much of Lake Superior today. A Gale Warning is in effect for most of the lake save for the far west.

DISCUSSION

Issued at 135 AM EDT Sat Apr 18 2026

As the cold front continues to slowly push through the U.P. early this morning, expect the rain showers and thunderstorms along it to progressively move out from west to east. With generally 0.25 to 0.50 inch of liquid seen over the area the past 24 hours, things are still fairly moist; the rainfall will help to keep local rivers elevated even as temperatures drop down into the 30s, as can be seen in the observations over the far west already behind the cold front early this morning. In addition, an area of the interior west from Iron County to Baraga County has received over 1 inch of rainfall in several spots. With the rainfall and snowmelt exceeding the 3 and 6- hour Flash Flood Guidance, hoisted up a Flood Warning over northern Iron County and much of the higher terrain of Baraga County this morning after a Flash Flood Warning and Flood Advisory were issued earlier. Some roadways may be covered/inundated with water in this area; turn around and don't drown! The Flood Warning for the area continue until around dawn this morning; the Warning may need to be updated and extended or at least downgraded into a Flood Advisory later this morning as any flooding occurring over there may struggle to percolate into the soil for several hours as the ground is still saturated.

Behind the cold front expect drier conditions and cooler temperatures as lake effect cloud cover moves overtop Upper Michigan for the weekend. While delta-Ts and the strong west to northwesterly winds over Lake Superior are sufficient to produce lake effect snow showers across much of the area today through Sunday, with dry air at the sfc eating away at the snowfall, expect accumulations to be very limited across the region, mainly up to a dusting or so in the higher terrain areas in the west to northwest wind snow belts. Otherwise, expect generally some flurries from time-to-time across the area today through Sunday. While highs today and Sunday will be relegated to the 30s near Lake Superior, the cooler temperatures will aid in alleviating flooding concerns over the U.P. as snowmelt of the remaining snowpack will slow down. In addition, the cooler conditions will also bring about drier conditions as well, which should help reduce/get rid of flooding over portions of the U.P. this weekend into early next week as soils can finally dry-out a little.

Expect the dry conditions to continue through next week as a gradual warming trend brings more pleasant Spring-time temperatures back across the area by mid-week. While a cold front is looking to drop down from northern Ontario around the Monday night time period, precipitation is not expected from it and impacts are looking to be next to nil. Another low pressure system developing over the Northern Plains by the middle of next week may skirt over the Keweenaw and bring showers and storms to that area come Thursday. However, this will be highly dependent on how the low tracks over the Northern Plains, and confidence in the low's track is still low at this time. However, confidence does increase on the low's cold front moving through the area around the end of next week. This cold front synoptically looks very similar to the one going through our area this morning, and could bring rain showers and thunderstorms across the entire U.P. as it pushes through the region.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 700 AM EDT Sat Apr 18 2026

Prevailing MVFR stratus at all sites lingers through the morning before lifting to VFR this afternoon. Gusty WSW winds between 20 and 25 kts will be common today with gusts to 35 kts at CMX. Winds slowing diminish below 25 kts late tonight.

MARINE

Issued at 135 AM EDT Sat Apr 18 2026

Behind a cold front moving through the lake early this morning, a few westerly gale force gusts up to 35 knots could be seen from time- to-time before dawn. As the main shot of cold air advection moves through the region during the daylight hours today, expect the winds to increase from the west to northwest across Lake Superior, becoming gales of 35 to 40 knots across most of the lake (save the far west); therefore, a Gale Warning has been issued for a majority of the lake today. As the cold air advection wanes tonight into Sunday, expect the winds to gradually slow with time, eventually becoming 20 knots or less by Sunday night. However, a dry cold front moving through on Monday night could bring south to southwesterly gales back over the eastern half of the lake; as of right now, the NBM has a 40 to 50% chance for low-end gales. Once the cold front passes by Tuesday morning though, expect the winds to weaken down to 20 knots or less again by the afternoon hours, with the light winds continuing through Wednesday.

HYDROLOGY

Issued at 150 AM EDT Sat Apr 18 2026

While generally one quarter to half an inch of rainfall was seen across the area this previous evening through early this morning, areas of the interior west (namely Iron County and the higher terrain areas of Baraga County) have had several spots receive well over an inch of rainfall. With Flash Flood Guidance having been exceeded by 200%+ in several basins, a Flood Warning was hoisted up for this area after a Flash Flood Warning and Flood Advisory were previously issued. The Flood Warning may need to be extended for longer later this morning as the saturated soils will have a difficult time reducing any areas of inundation, even as temperatures drop and snowmelt decreases.

Because of the rainfall this past evening/this morning and accelerated snowmelt that we've seen the past several days, U.P. rivers will continue to climb today in response to the extra liquid being introduced to the sfc. However, as the cooler and dry weather continues through the weekend into next week, expect the flooding concerns to gradually dwindle across the area as we finally start to dry out and snowmelt decreases (at least for this weekend).

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Flood Watch until 8 AM EDT /7 AM CDT/ this morning for MIZ001- 003>007-010>014-084-085.

Lake Superior... Gale Warning from 11 AM EDT /10 AM CDT/ this morning to 8 PM EDT /7 PM CDT/ this evening for LSZ241>243-263.

Gale Warning from 11 AM this morning to midnight EDT tonight for LSZ244-264.

Gale Warning from 1 PM this afternoon to 8 PM EDT this evening for LSZ245>248-265.

Gale Warning from 2 PM this afternoon to 8 PM EDT this evening for LSZ250-251-267.

Gale Warning from 1 PM this afternoon to midnight EDT tonight for LSZ266.

Lake Michigan... None.