Storms overnight; next wildfire smoke wave by Sunday?

It’s a tale of two wind directions for Minnesota this summer.

The south wind brings us steamy (but generally smoke-free) tropical air masses. Temperatures Friday afternoon hit the 90s in southeast Minnesota and we made it to 90 degrees for the 11th time this year in the Twin Cities. That’s about average for an entire year in the Twin Cities with several more weeks of summery weather still ahead.

Dew points have surged well into the steamy 70s all the way to the Iron Range and to the oppressive 80s in southeast Minnesota. Here are some select temperature and heat index values late Friday afternoon.

Location Temperature Heat Index

• MSP Airport 90 degrees 99 degrees

• Mankato 86 degrees 97 degrees

• Owatonna 86 degrees 98 degrees

• Winona 90 degrees 98 degrees

• Preston 86 degrees 102 degrees (dew point 81 degrees!)

The heat advisory was dropped early for the Twin Cities area Friday. It will still be very warm and steamy out there through Friday night.

Storms overnight

A cool front in the eastern Dakotas slicing into our unstable tropical air mass will spark strong storms overnight. NOAA’s HRRR model is typical of many that develop a line of storms in western Minnesota around 6-7 p.m. Friday. The line will track eastward through central Minnesota likely reaching the Twin Cities through Duluth areas after midnight.

There is a slight risk for severe storms across most of Minnesota overnight into early Saturday. Stronger cells will be capable of producing damaging winds, large hail, torrential downpours and a vivid lightning show overnight.

Stay alert for possible severe weather watches and warnings in your area. This will be a good night to have the NOAA weather radio fired up.

Next smoke wave Sunday

The north wind this summer brings smoky skies to Minnesota.

But Saturday looks pretty good with mixed sunshine and highs in the 70s north to 80s south.

The next wave of wildfire smoke looks likely to drift across Minnesota Sunday into Monday. Air quality Sunday looks poor in the north and not great in the south.

They got some rain in some of the fire zones in Canada this week. So there’s uncertainty in how thick and long-lasting the next wave of smoke will be. That’s why MPCA is holding off on an air quality alert for now until they get a better picture of smoke distribution and thickness Saturday.

Here the latest forecast discussion from MPCA.

Updated Fri, Aug 8, 2025

KEY MESSAGES: 1.) Heavy surface smoke will likely impact Minnesota on Sunday and Monday - confidence is greatest across central and northern Minnesota. DETAILED DISCUSSION: Southern Minnesota has observed low-end Yellow AQI today (Friday) due to fine particle pollution, but the rest of the state has and will continue to have Green (good) air quality. An area of low pressure will move across south central Canada this weekend, and heavy surface smoke from numerous wildfires across Saskatchewan and Manitoba will wrap in behind it. Parts of Montana and the Dakotas will be impacted on Saturday, and western Minnesota will be impacted beginning either Sunday morning or afternoon. Smoke should spread east through Sunday evening, and then disperse from west to east throughout the day on Monday. Two sources of uncertainty have prevented an issuance of an air quality alert this Friday afternoon - how far south will the heavy smoke get, and how heavy will the smoke be across Minnesota. If an air quality alert is needed, as is currently expected, it would be issued Saturday afternoon for this Sunday-Monday event. As for ground-level ozone, concentrations may reach the Yellow (moderate) AQI category in and around large urban areas during the afternoons through at least the first half of the week, due to plenty of afternoon sun and above average temperatures. Additional surface smoke may move into northern Minnesota on Tuesday due to what will most likely be northwest winds across southern Canada, but recent rains in/around relevant Canadian wildfires introduces uncertainty in concentrations.

Stay tuned.