textproduct: Marquette

KEY MESSAGES

- Active weather returns tonight and continues through much of at least the first half of next week as several periods of showers and thunderstorms are poised to move through the region.

- A prolonged period of well above freezing temperatures and higher dewpoints will bring increased snowmelt. This, combined with periods of potential heavy rain and thunderstorms, will accelerate river rises and lead to ponding of water in areas with poor drainage. A Flood Watch remains in place for all of Upper Michigan tonight to Wednesday morning.

DISCUSSION

Issued at 302 PM EDT Sat Apr 11 2026

As temperatures continue to rise in the pleasant, mostly sunny weather early this afternoon, dewpoints continue to remain below freezing as weak high pressure ridging (which is currently exiting the area) is allowing for sub-freezing dewpoints to remain at the sfc. With temperatures continuing to rise into the 40s and 50s this afternoon, expect RHs across much of the interior U.P. to drop to around 30% (maybe even the upper 20 percents) as the dewpoints take their sweet time rising as Gulf moisture approaches from the south- southwest. Thus, while snowmelt is still occurring, expect it to continue being gradual this afternoon.

The pattern changes tonight though as a warm front from a low pressure system developing out of the lee of the northern Rockies pushes into the region tonight through Sunday. With the arrival and passage of the warm front comes rain showers and thunderstorms, with some of the convection being heavy at times, especially over the south central where the confidence in heavy rainfall is the highest (the latest HREF run has 50-70% chance over an inch of rainfall falling in the south central between tonight and Sunday evening). While the north central and east have the next-best chances for receiving heavy rainfall tonight through Sunday due to the warm front, model spread is higher over these areas (particularly the north central) as the convective nature of the rainfall could cause some spots to have a relative glut of rainfall while others receive less. As for the western U.P., the least amount of rainfall is expected with the passage of the warm front, with only around a half to three-quarters of an inch expected (chances for greater than an inch of liquid limited to 10 to 30%). While a temperature inversion as well as cloudy skies are expected tonight through Sunday thanks to the warm front, expect robust advection from the Gulf to bring highs into the 50s and 60s on Sunday as lows tonight are expected early, mainly in the mid 30s to lower 40s as temperatures increase late tonight. In addition, dewpoints at the sfc are projected to finally warm via the rainfall and Gulf moisture, eventually soaring into the 50s by late Sunday. While the inversion near the sfc associated with the passage of the warm front should somewhat limit the strong LLJ at 850mb from reaching the sfc, we could see winds increase up to 30 mph in the downslopes near Lake Superior as the inversion at around 925mb looks to not be too robust to hinder all the mixing. With NOHRSC analysis showing temperatures in the remaining snowpack already being right at freezing, the snowmelt across the area is expected to accelerate tonight through early next week. This in combination with the heavy rainfall in some of the area could bring localized flooding via ponding of water in low- lying and poor drainage areas. Therefore, if you see any flooded areas the rest of this weekend through early next week, avoid the area and try to go around it; turn around, don't drown. As for the severe weather threat tonight through Sunday, expect the CAPE associated with the convection to be locked-up in the mid-to-upper levels of the atmosphere. While the hodograph looks pretty impressive and indicative for severe weather tonight through Sunday, given that the shearing profile becomes much more limited above the inversion in the lower levels (which is where the CAPE is), thinking chances for severe weather tonight into Sunday will be very low (2% or less). If any severe weather does occur, thinking it will be marginal hail as the inversion in the lower levels should prevent severe winds and from reaching the sfc. Behind the warm front, a shortwave low rotating through the Northern Plains looks to potentially bring additional convective showers and storms across the area late Sunday before it's cold front moves through Sunday night. While the temperature inversion looks to weaken near the sfc later in the day Sunday to Sunday night along and just behind the cold front, with the winds aloft weakening I'm thinking the chances for severe thunderstorms will remain very low (2% or less) at this time. Nevertheless, I do think that the chance for severe winds will become a little higher late Sunday through Sunday night as drier air aloft is able to be mixed into the mid-to-upper level of the atmosphere as PWATs decrease.

While a quick reprieve from the active weather is expected Monday, another shortwave low is projected to move through the Upper Great Lakes Monday night through Tuesday. As this occurs, additional, rain showers and thunderstorms are expected, potentially bringing heavy rainfall at times back across the area. The rainfall may exacerbate or spread any ponding of water or river flooding we see across the area, especially as well above normal temperatures and dewpoints continue across the area thanks to Gulf moisture being advected into the area (although the advection is not going to be as strong as it will be tonight through Sunday). In addition, expect a north-to- south temperature gradient to begin forming, with highs in the lower 40s over the northern Keweenaw to near 70 in the south central near Wisconsin Tuesday and Wednesday. One last low pressure system looks to move through on Wednesday, bringing additional showers and thunderstorms to the area before weak high pressure ridging moves back overhead for Thursday. With dewpoints well above freezing across most of the area for the first half of next week (save for maybe the northern Keweenaw), thinking a large portion of the U.P. could be snow-free by the time the weak high pressure arrives around Thursday. However, with around 9-12 inches of SWE still remaining near Lake Superior as of yesterday, thinking the Keweenaw and spots near Lake Superior could still have some spots of snowpack remaining by the middle of next week.

A train of Colorado shortwave lows looks to move through the area to end next week and next weekend as colder Canadian air pushes down the Canadian Prairies and Northern Plains late. Thus, thinking we may see some more active weather to round-out next week. This, in turn, could impact flooding across the area. For additional information specifically on flooding concerns due to the combination of rain and snowmelt, please see the Hydrology section below.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 157 PM EDT Sat Apr 11 2026

VFR conditions prevail at all sites through this evening as high pressure lingers over Upper Michigan. Conditions lower to MVFR from west to east 00-06z Sun as rain spreads into the region, with further deterioration to IFR possible at the terminals after 06z. Added a PROB30 for TSRA to KIWD after 06z Sun as thunderstorm potential has increases across the west. Still can't rule out a few thunderstorms at other U.P. terminals tonight into Sunday, but probs remain too low for inclusion in KCMX and KSAW TAFs. LLWS will also be a concern as LLJ moves overhead tonight, accompanied by gusty south winds at the surface. Rain showers slowly diminish in coverage in the west near the end of the period, but expect cigs to remain MVFR or lower through 18z Sun.

MARINE

Issued at 302 PM EDT Sat Apr 11 2026

Winds, which have weakened to 20 knots or less early this afternoon, restrengthen to southeast to southerly winds of 20 to 30 knots tonight into Sunday as a warm front pushes into and through the region. While the NBM brings low-end gale chances up to around 30% in the eastern open waters (especially closer to the international border), thinking the low-end gale force gusts will be limited; thus, no Gale Warning has been issued with this afternoon's forecast package. While another shortwave rotates into the area Sunday through Sunday night, with the temperature advection from the shortwave being fairly weak, expect only south to southwesterly winds of 20 to 25 knots ahead of the cold front Sunday night, with winds of 20 knots or less seen behind it. Throughout this period from this evening into Sunday night, expect rain showers and potentially a few thunderstorms. While not expected, there is technically a non-zero chance for severe weather in the thunderstorms, namely marginally severe hail (around quarter-sized).

After a quick reprieve from the active weather during the day on Monday, another shortwave low moves over the Upper Great Lakes Monday night through Tuesday. Besides additional showers and thunderstorms potentially moving across Lake Superior, expect winds to back to the northeast to around 20 knots Monday night before weakening Tuesday. After another quick reprieve Tuesday night, a low pressure system could potentially move over Lake Superior on Wednesday. While this system could bring additional rain showers and thunderstorms to the lake, winds as of right now are still currently slated to remain at 20 knots or less before and after the low's passage. Weak high pressure ridging building in on Thursday looks to keep the winds and weather quiet over the lake as we begin heading towards the end of next week.

HYDROLOGY

Issued at 302 PM EDT Sat Apr 11 2026

The slow snow melt seen over the past few days gives way to accelerated melting tonight through Wednesday morning as the latest NOHRSC analysis shows the remaining snowpack ripe for melting (snowpack temperature at freezing). In addition, with temperatures, dewpoints, winds, and heavy rainfall chances increasing, expect potentially significant river rises early next week given the expected rainfall and favorable melting conditions.

With a robust Gulf connection supplying very warm, moist air to the Great Lakes region early next week, expect temperatures to warm up generally into the 50s and 60s, save for maybe the northern Keweenaw after Sunday. Temperatures remain above freezing tonight and warm with time a couple of hours after sunset...beginning a prolonged period of well-above freezing temperatures and dew point temperatures.

Sunday and Monday are the focus of highest temperatures, with forecasts ranging 10 to 20 degrees above normal (Normal Highs: 40s to low 50s, Normal Lows: 20s to 32) as parts of the U.P. get placed underneath the warm sector. The going forecast has highs in the 50s and 60s, warmest in the interior west on Sunday and in the south- central on Monday. There is a 40-80% chance of exceeding 70 near the WI/MI state line on Sunday and Monday. Lows are expected in the 40s to mid 50s Sunday night and mid 30s to mid 40s Monday night (15 to 30 degrees above normal Sunday night!). During this period dewpoint temperatures soar into the 50s by late Sunday, remaining elevated into Monday night even after the cold front of a shortwave low passes. Winds south to southwesterly winds around 10-20 mph will support heat transfer near the surface tonight through Sunday night, increasing snow melt efficiency.

With this warmth and moisture comes showers and thunderstorms. Precipitation could be heavy at times, especially in the south central where the latest HREF LPMM run shows a 24 hour rainfall total between tonight and Sunday evening of around 3 inches near the city of Menominee 1 to 1.25 inches in the north central, around 0.75 to 1 inch in the east, and around 0.5 to 0.75 inches in the Keweenaw and west. This is even corroborated by the NBM (which has lower QPF), as even it shows 20-70% chances for above 1 inches in 24 hours ending 8 PM EDT Sunday (highest in the south central near Menominee, lowest in the Keweenaw and far west). Stronger rain showers and storms may bring heavy downpours in spots, as reflected by the NBM 75th and 90th percentiles showing amounts of 1.25 to 2 inches within the same 24 hour period. While some convection may also be seen late Sunday through Sunday night as the cold front of a shortwave passes through, expect less widespread rainfall amounts even as downpours could be heavy in some of the showers and storms. A second round of showers and possibly thunderstorms moves through Monday night into Tuesday as shortwave low moves through the Upper Great Lakes. Mean rainfall amounts predicted with this shortwave's passage are between 0.5 to 1 inch of rain with stronger showers/storms reaching up to 1.25 to 1.5 inches of rainfall (as seen via NBM90th percentile). Additional precipitation is anticipated into mid next week as one final low pressure system is expected to move through Lake Superior on Wednesday.

All these factors lead to accelerated rate of snowmelt and increasing likelihood of ponding of water on low-lying/poor drainage areas as well as minor river flooding. A Flood Watch remains in effect for the entire U.P. tonight through Wednesday morning to account for these concerns. Moderate river flooding remains possible on the Paint River near Crystal Falls and the Sturgeon River near Alston (now up to a 45-60% chance in these locations); see the latest River Flood Statements for additional information. In addition, chances for at least Minor river flooding are increasing for areas such as the Black River at Bessemer, the Chocolay River at Harvey, the Middle Branch of the Escanaba River at Humboldt, the Eastern Branch of the Escanaba River at Gwinn, the Sturgeon River near Nahma Junction, and the Tahquamenon River near Paradise (now up to a range of 30-60%, save for near 90% at Gwinn, near Nahma Junction, and near Paradise). 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... Flood Watch from 8 PM EDT /7 PM CDT/ this evening through Wednesday morning for MIZ001>007-009>014-084-085.

Lake Superior... None. Lake Michigan... None.