textproduct: Marquette

KEY MESSAGES

- Westerly gales up to 35 knots are expected along and north of the north shore of the Keweenaw through this morning.

- Expect gradual snowmelt and river rises the rest of this week as high temperatures get into the 40s and 50s.

- Active weather resumes late this weekend along with even warmer temperatures. A prolonged period of well above freezing temperatures and higher dewpoints will bring increased snowmelt. This, combined with periods of rain showers and potential thunderstorms will accelerate river rises.

DISCUSSION

Issued at 215 AM EDT Thu Apr 9 2026

Early this morning surface analysis showed an elongated 1005mb low pressure moving through southwestern Ontario and northern Lake Superior, with a cold front extending through the eastern U.P. Showers were pushing through the far eastern U.P. along the frontal boundary. Temperatures were in the 30s across the west and north but still in the 40s over the east and far south (Menominee County).

The sfc low pressure will quickly track northeast today, reaching James Bay by early afternoon and pushing through northern Quebec this evening. In its wait high pressure will build into the area bringing mainly dry conditions through Friday with the exception of the Menominee area which will have a low chance for light rain showers, possibly mixed with snow tonight as a trailing shortwave moves through the area. Temperatures today will range from the 30s over the Keweenaw to the low 50s around Menominee. Winds could gust 25-30 mph this morning as pressure gradient remains fairly tight and caa aloft and sfc heating will promote mixing. Winds should diminish during the afternoon hours as high pressure builds in and the pressure gradient relaxes. There is also some low level moisture and instability that should help develop a low cloud deck this morning. Some of the CAMs have spotty showers in the modeled reflectivity, however, the instability is very shallow and sub-cloud air is on the drier side with inverted-v type soundings. Will leave out the mention of precip but wouldn't be surprised to see some flurries or sprinkles today, especially over the central and west.

Moving into Friday and Saturday expect fairly zonal flow giving way to ridging on Saturday. This synoptic setup is looking to continue high temperatures in the 40s and 50s across the area, with some areas near the Wisconsin border potentially sneaking up to the lower 60s by Saturday. In addition, dewpoints are looking to remain below freezing for the work week, although as Gulf moisture begins to pump into the region on Saturday we may see dewpoints rise above freezing then (around a 30 to 50% chance according to the 00z LREF run). With drier weather expected during this time period (save for a less than 25% chance for precipitation by the city of Menominee Thursday night) and with lows getting below freezing Thursday and Friday nights, expect the remaining snowpack to only slowly melt away. Thus, we can expect river flooding risks over the next couple of days to be rather limited as river rises from snowmelt will be slow and small.

However, this looks to change late this weekend as a low pressure system moving off of the lee of the northern Rockies starts to bring precipitation to the region Saturday night. As the warm front of the low moves into the region Saturday night, expect convection in the form of rain showers and non-severe thunderstorms to return to the area. With PWATs increasing to over an inch Saturday night and with fairly robust lift within the warm front, the convection could bring heavy rainfall to portions of the area. As we continue under the warm sector of the low pressure Sunday through Monday, expect highs to soar into the 50s and 60s, with the NBM showing up to a 40% chance for temperatures above 70 in the south central and interior west near Wisconsin on Monday. In addition, with moisture still being pumped in from the Gulf, convective showers and thunderstorms look to continue through early next week as dewpoints climb well above freezing into the 50s, even during the overnight hours. Thus, the very warm and moist air in conjunction with rainfall, potentially heavy at times) could increase snowmelt across the remaining snowpack and thus accelerate river rises across Upper Michigan. In addition, the convective rainfall could also produce ponding of water in low-lying and poor drainage areas. Therefore, we will continue to monitor this situation as it continues to evolve as at least minor river flooding could become more apparent next week. That being said, confidence is already high enough in minor flood stage being achieved at Alston along the Sturgeon River in northwest Baraga/eastern Houghton counties that a Flood Warning was issued last night; decided to keep it going with this afternoon's package as the river forecast from the North Central RFC didn't deviate from what was expected last night. Behind the low, expect cooler temperatures as colder air from Canada attempts to push in from the north next Tuesday and Wednesday.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 809 PM EDT Wed Apr 8 2026

Rain continues to overspread TAF sites this evening in association with a cold front. As a result, expect widespread MVFR flight restrictions by Thu 03Z and tempo IFR at SAW. In addition, south- southwest winds will gust to 30 to 35 kts with a LLWS threat at CMX and SAW this evening. As precipitation exits to the east between Thu 04-06z, look for a return to VFR for most terminals before a period of MVFR cigs again around mid-morning tomorrow. Also, winds shift westerly behind the front and continue to gust to 20-25 kt through mid-morning tomorrow.

MARINE

Issued at 215 AM EDT Thu Apr 9 2026

Cold air advection behind a front and a tight pressure gradient this morning will result in winds increasing from the southwest to west to 20 to 30 knots across the lake, with westerly gales up to 35 knots expected along and near the north shore of the Keweenaw; therefore, a Gale Warning remains in effect through 10 AM EDT this morning. As the troughing behind the cold front deteriorates and more zonal flow aloft takes its place on Thursday, expect the winds to progressively weaken with time as they slowly veer to the northwest. By Thursday evening, expect the winds to die down to 20 knots or less and to remain that way until Saturday evening. As a low pressure system lifts off of the northern Rockies on Sunday, expect the low's warm front to move into the region and begin increasing winds from the southeast and south Saturday night (as well as bring showers and thunderstorms). Expect winds of generally 20 to 30 knots over mostly the eastern half of the lake by Sunday as convection looks to generally continue through early next week. As the low lifts over northern Ontario towards James Bay on Monday, a second low pressure system looks to move towards the Upper Great Lakes from Colorado. Thus, while winds look to weaken as the progressively back with time Sunday night through Monday, expect the winds to remain elevated above 20 knots.

HYDROLOGY

Issued at 215 AM EDT Thu Apr 9 2026

A slow snow melt is expected to give way to accelerated melting this weekend as the snowpack becomes ripe for melting and rain chances increase. Expect limited melting through Friday as temperatures rise into the 40s but low dew points and temperatures below freezing at night mitigate melting.

River rises are expected this weekend into early next week as snowmelt accelerates and rain chances increase. A warm front associated with a low pressure system lifting off of the northern Rockies moves over the area Saturday night into Sunday. With the warm, moist air of the Gulf remaining overhead Saturday night through Monday, expect temperatures to remain above freezing and for high temperatures to get into the 50s, 60s, and potentially 70s (warmest temperatures expected on Monday). In addition, dewpoints appear to soar into the 50s as winds pick up from the south. Convection could bring heavy rainfall at times, with the NBM showing probabilities of an inch or more of rainfall at around 40 to 70% across the area between Saturday night and Monday evening. Thus, given the accelerated rate of snowmelt and increasing chances for heavy rainfall, the likelihood for ponding of water on low-lying and poor drainage areas and for river flooding is increasing. Therefore, those living near and planning to recreate around the rivers and low- lying areas of the U.P. early next week should keep up with the forecast and river levels as the snowmelt and rainfall amounts will determine flooding potential.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning until 10 AM EDT this morning for LSZ243-244-264.

Lake Michigan... None.