Area Forecast Discussion

KEY MESSAGES

- The threat for flooding continues, but will decrease through today as cooler weather continues, slowing snowmelt.

- Flurries/light snow showers are possible into tonight, mainly over the east half. Otherwise predominantly dry weather persists through the middle of next week.

- With the sfc drying out and temperatures increasing from Monday onwards, the chance for elevated fire weather conditions is beginning to increase from Monday to Wednesday.

- There is a 40% chance for south to southwesterly gales up to 40 knots over eastern Lake Superior Monday night.

DISCUSSION

Issued at 212 AM EDT Sun Apr 19 2026

Cooler temperatures are expected to continue through today as radar imagery shows lake effect snow showers beginning to move into the U.P. early this morning. Although there still remains a lot of dry air near the sfc, given delta-Ts in the mid-teens and strong winds still occurring over Lake Superior today, expect the lake effect snow showers to bring a dusting to potentially up to an inch of new snowfall to portions of the northwest wind snow belts today into tonight, mainly over the east half as troughing will be better further east as high pressure pushes in from the west today into Monday. However, given the high April sun angle, thinking any new accumulations seen today and tonight will melt or evaporate away during the daylight hours, so impacts look to be fairly small and limited to the morning hours today and potentially Monday morning. With cold air remaining overhead today, expect some spots to fail to get above freezing; that being said, areas outside of the northwest wind snow belts (such as the south central) could still sneak into the lower 40s thanks to breaks in the cloud cover. In addition, expect lows this morning and tonight to drop down into the 20s in the interior areas, with the teens being possible tonight. Therefore, wait to plant anything as frost is possible early this morning and even moreso tonight into Monday morning.

River flooding and ponding of water is still occurring across several areas of Upper Michigan (save for the far west). However, given the cooler temperatures today, river rises caused by snowmelt will decelerate; in fact, we may begin to see some river levels across the area decrease today and potentially even Monday as snowmelt becomes limited over the next several hours. With drier conditions expected through most of the rest of the week (a.k.a. until around Friday), expect to see ponding of water in low-lying and poor drainage areas decrease or cease altogether. That being said, we may see river rises once again in the north central, Keweenaw, and east later this week as warming temperatures return and accelerate snowmelt in the remaining snowpack once again, where several inches of liquid still remain. However, looking at the latest HEFS and NCRFC forecasts, the river levels over these areas do not look to be as high as they are now.

Given the drying expected this week, we may see RHs fall into the 20 percents or potentially even lower from Monday to Wednesday. As of right now, the forecast for Monday has RHs getting into the teen percents by Monday afternoon as warm air advection pushes into the region and a LLJ moves in overhead. Will continue to monitor this situation as the dry conditions have the potential to create some elevated fire weather conditions this week (we have yet to experience our Spring 'green-up'). However, Gulf moisture looks to begin returning to the area around Thursday, and a cold front looks to potentially bring showers and thunderstorms back to the U.P. Thursday night through Friday. Behind the cold front, expect cooler temperatures that are not too dissimilar from what we are experiencing now.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 137 PM EDT Sun Apr 19 2026

VFR conditions are ongoing at IWD and SAW with high-end MVFR conditions at CMX due to ongoing lake effect snow flurries that are also observed occasionally at SAW. Given the lack of model support for continued MVFR conditions at CMX, will put the current ongoing conditions in a TEMPO group. High pressure moving over the area will gradually bring an end to precip tonight as well as reducing the winds to being light and variable. SW winds do increase to 5-10 kt with gusts near 15 kt Monday afternoon.

MARINE

Issued at 212 AM EDT Sun Apr 19 2026

While a few northwest gale force gusts up to 35 knots are possible early this morning, expect the northwest winds of 20 to 30 knots across the lake to slowly dwindle down with time today, eventually becoming 20 knots or less by late tonight as sfc high pressure ridging pushes into the region. However, don't expect the lighter winds to stay around for that long as a dry cold front dropping down from northern Ontario Monday night is looking to increase winds from the south to southwest by Monday afternoon; currently, the NBM has a 40% chance for gales up to around 35 knots over the eastern open lake near the International border Monday night. After the dry cold front passes through late Monday night/early Tuesday, expect the winds to calm back down to 20 knots or less across the lake by late Tuesday morning. The light winds look to continue until around Thursday, when increasing warm air advection from the Gulf is looking to bring southeast to southerly winds of 20 to 30 knots back across the area ahead of a robust cold front; as of right now the NBM is bringing around a 25% chance for low-end gales over the eastern lake on Thursday, increasing to over 30% Thursday night ahead of the cold front. Expect some rain showers and thunderstorms over the area Thursday night through Friday, with the cold front pushing through on Friday. Behind the cold front, expect west to northwest winds of 20 to 30 knots across the lake.

MQT WATCHES / WARNINGS / ADVISORIES

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