textproduct: Marquette

KEY MESSAGES

- Benign weather continues through this afternoon.

- Active weather returns tonight and continues through much 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 through Wednesday morning.

DISCUSSION

Issued at 358 AM EDT Sat Apr 11 2026

Early morning GOES satellite imagery reveals mostly clear skies across the Upper Great Lakes under the influence of surface high pressure. A weak shortwave embedded within the ridging aloft skirting through Ontario is allowing cloud cover to preside across Lake Superior and portions of the central and east. Temps are coming in largely around freezing, with some cooler mid to low 20s seen across the east half. Today, expect high pressure to dominate through much of the day, leading to benign and quiet weather with plenty of morning and afternoon sunshine. Soundings across the interior west and central show a good amount of mixing into a dry layer aloft where afternoon surface RHs may dip into the 20s and 30s again, similar to yesterday. Given light southerly winds and healthy snowpack still covering a majority Upper Michigan, there are no fire weather concerns. Otherwise, daytime highs will make a run toward 60F for the SW UP. The northern and eastern tier stay a bit cooler in the upper 40s to low 50s.

An active weather pattern kicks off tonight into Sunday as western troughing and SE US ridging open up the metaphorical flood gates for strong warm and moist advection from the Gulf northward into the Upper Great Lakes. Showers and a few embedded thunderstorms (non- severe) develop across the Upper MS Valley tonight, lifting into the UP this evening and into the overnight hours through early Sunday. Ample moisture advection (IVT and PWATs in the 99th to max percentile of NAEFS climatology) provides additional confidence in moderate to heavy rainfall, especially within convection. Latest NBM and LREF ensembles suggest only a 30-60% chance for 24hr rainfall amounts >1" (highest south central and east) through Sunday evening, while the 00z HREF generally depicts pockets of 1-1.5", which may be more realistic given convective elements and high end moisture profiles. Rainfall coupled with dewpoints climbing above freezing will lead to accelerated snowmelt. A Flood Watch remains in effect tonight through Wednesday as warm and wet weather continues into the work week. In addition to the rain, breezy S to SW winds upwards of 20-30 mph will be common, especially for areas of the north central where downsloping locally enhances winds running down the terrain. 850mb temps soaring between 10-12C will translate to surface temps reaching mid 60s across the west and s-central. Mid to upper 50s will be seen in the Keweenaw and east half.

The pattern will remain conducive to ongoing hydro concerns through much of next week as southwest flow aloft becomes established over the Great Lakes downstream of persistent troughing over the western CONUS, paving the way for additional systems to bring periods of rain and thunderstorms during the middle and latter parts of the week. After a brief reprieve on Monday, a second round is becoming more likely late into Tuesday morning. The latest ensemble suite suggests a conglomerate 40-70% chance for an additional 0.5" by Tuesday afternoon. Locally higher (and lower) amounts are possible given convective potential. Meanwhile, low level southerly flow will maintain a feed of rich gulf moisture and help to keep high temperatures in the 50s and 60s through the end of the week while overnight lows stay above freezing over most of the UP. See the Hydrology section below for a additional information on flooding concerns due to the combination of rain and snowmelt.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 710 AM EDT Sat Apr 11 2026

VFR conditions through this evening at all TAF sites, but look for deterioration to MVFR in the Sun 00-06Z time frame as rain showers overspread the TAF sites. Ceilings drop further to IFR at CMX and SAW after 06Z. Isolated thunderstorms also cannot be ruled out, but confidence is not high enough at this time to include mention. Additional threat includes LLWS at IWD starting around 06Z, then at CMX and SAW by 09Z.

MARINE

Issued at 358 AM EDT Sat Apr 11 2026

High pressure descending into the lower lakes will keep winds light and variable through tonight. Southeast winds increase tonight as low pressure develops off the Northern Rockies and high pressure shifts to the east. An associated warm front lifting through also brings showers and thunderstorms. Expect winds of 20-30 kt over the eastern two thirds of the lake by early Sunday morning, continuing into Sunday afternoon. NBM guidance continues to highlight low (<30%) probability for gales to 35 kts Sunday morning and early afternoon for the open waters east of the Keweenaw, however, its worth noting that the ECMWF Ens suggests a 50-80% chance for Gales of 35 kts for the typical downsloping locations of the north central and eastern UP nearshore locations between Marquette and Grand Marias. These localized accelerated winds may spill 35 kt gusts into the immediate nearshores, though internal confidence is low regarding exact locations and extent into the open water, if this occurs at all. At this time, opting to forego any Gale headlines.

Winds briefly fall back below 20 kt across the lake Monday morning, but increase to 25-30 kt out of the NE Monday night into Tuesday as another low pressure system moves towards the Great Lakes. Chances for gales are much lower with this system, remaining 15% or less at this time. The active period continues through at least mid next week as a third system keeps winds in the 20-30 kt range.

HYDROLOGY

Issued at 330 PM EDT Fri Apr 10 2026

A slow snow melt gives way to accelerated melting this weekend as the snowpack becomes ripe for melting (snowpack temperature reaching freezing) and rain chances increase. River rises are expected this weekend into early next week given the expected rainfall and favorable melting conditions.

The remainder of the weekend into early next week sees a fairly persistent Gulf connection into the Great Lakes, bringing warm and moist air into the region. Temperatures warm up on Saturday into the mid 40s to mid 50s with widespread dewpoint temperatures just eclipsing freezing. Temperatures broadly remain above freezing Saturday night...beginning a prolonged period of 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 UP get placed underneath the warm sector. The NBM currently has highs in the 50s and 60s, warmest in the interior west on Sunday and in the south- central on Monday. There is a 30 to 50% chance of exceeding 70 near the WI/MI state line on Sunday and a 40 to 60% chance in the south- central on 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 mid 40s to mid 50s Sunday, remaining elevated into Monday night. Winds around 10-15 mph will support heat transfer near the surface, increasing snow melt efficiency.

With this warmth and moisture comes showers and thunderstorms. Precipitation could be heavy at times, with the NBM showing 40-50% chances for above 1 inches in 24 hours ending 8 PM EDT Sunday. Stronger storms may bring amounts of 1.25 to 2 inches in 24 hours reflected in the NBM 75th to 90th percentiles. A second round of showers and possibly thunderstorms Monday night into Tuesday brings mean rainfall amounts between 0.5 to 1 inch of rain with stronger showers/storms reaching up to 1.25 to 1.6 inches of rainfall. Additional precipitation is anticipated into mid next week.

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 has been issued for the entire U.P. from Saturday night 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 45-50% chance in these locations). See the latest River Flood Statements for additional information. 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 this evening through Wednesday morning for MIZ001>007-009>014-084-085.

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