textproduct: Twin Cities

KEY MESSAGES

- Ongoing storms this morning producing occasional wind gusts near 45 to 55 mph, becoming more scattered by mid morning.

- A short period of hazardous heat and humidity Monday afternoon before turning cooler for midweek.

- Hot temperatures return next weekend.

DISCUSSION

Issued at 355 AM CDT Mon Jul 20 2026

A well-developed line of storms is progressing through Minnesota early this morning well ahead of a boundary to the west. These storms have approached severe level winds, but have stayed within the 45 to 55 mph range for the strongest gusts. We expect storms to continue into western WI, and eventually wane off the further they decouple from the LLJ. The hi-res CAMs have had a horrible handle on the convection this morning, but the general idea of what we had been seeing with development early this morning ended up being our solution with this first wave. As the morning activity clears out to the southeast, it will be early enough for us to be able to recover ahead of our next chance for storms later today.

There is some indication that we could have development near the Minnesota River Valley in SW MN mid-late morning that could reach as far north as the metro, but it would be favored to stay closer towards the Mankato and Owatonna area. All of this potential storm activity will have an impact on temperatures and heat indices today. With the surge of more humid air to the south of the front, heat indices have the potential to climb into the triple digits for areas in southern MN during the early to mid afternoon. Even as the front moves through, the drier air could allow for more efficient mixing of warmer temperatures down to the surface. The urban heat island of the Twin Cities metro may see a period of heat impacts as well, but the boundary moving through in the afternoon should allow for quicker recovery this evening. There was little change to the SPC severe weather outlook for today, but main risk continues to favor areas south and east. After our morning storms, it seems much more likely that the majority of the Upper MS Valley remains dry. That said, the best chance for any storm development this afternoon would be between Rusk to Eau Claire Counties and east into central WI. Tied to the front will be a wave of some additional wildfire smoke, but it does not look to be as dense or long-lasting.

Behind this wave, cooler and less humid air will settle in. After over a week of consecutive 90+ degree days, highs will return closer to normal for mid week. We should also see nighttime lows drop into the 50s nearly areawide Tuesday and Wednesday night, allowing for a nice time to open up windows again. Deterministic and ensemble guidance favor a much drier pattern under northwest flow and a building by the end of the week. Any rain chances will come from more mesoscale features, and will be day to day. The main thing to watch with the building ridge this weekend, is our highs may climb right back up into the 90s again.

AVIATION /06Z TAFS THROUGH 12Z TUESDAY/

Issued at 1219 AM CDT Mon Jul 20 2026

Confidence has decreased for overall storm coverage early this morning. We have had just one cluster of storms that's now moving into west-central MN with little additional development elsewhere. This means our chances for any TSRA activity over the next few hours is mainly just tied to this one cell. There is still a capable environment for more development this morning, with the most likely area for this now shifting closer to the MN/WI state line. With these latest trends, we have adjusted all of the MN TAFs down to prob30s with all of the WI sites at tempos for TSRA. The less storms we have during the early morning hours, the better chance we will have for more additional development during the mid-late morning in MN. It's a scenario where until the environment is tapped into, there will be a lingering chance for storms.

Winds increase out of the northwest tomorrow afternoon behind the passing front, with gusts up to 30 kts in some spots. There may be impacts from wildfire smoke behind the front as well, but confidence is low on how dense the smoke will be.

KMSP...Adjusted our tempo group to a prob30 to show the decreasing confidence for storms during the morning rush hour. It is looking more likely that we will not have an incoming line of storms tonight, and our primary chance for TSRA will be tied to any additional development during the early morning. There is a scenario where KMSP does not see any storms during the early morning, which would increase the risk for storms during the late morning and early afternoon.

/OUTLOOK FOR KMSP/ TUE...VFR. Wind NW 10-15G25 kts. WED...VFR. Wind N/NW 5 kts. THU...VFR. Wind SW 5-10 kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...Heat Advisory from noon today to 6 PM CDT this evening for Anoka-Carver-Dakota-Goodhue-Hennepin-Ramsey-Rice-Scott- Washington. Heat Advisory from noon today to 7 PM CDT this evening for Blue Earth-Brown-Faribault-Freeborn-Le Sueur-Martin- Nicollet-Sibley-Steele-Waseca-Watonwan. WI...None.