textproduct: Twin Cities

KEY MESSAGES

- Scattered thunderstorms are expected to develop this evening along and north of the I-94 corridor. These storms will be elevated, with an isolated risk for large hail existing.

- A line of strong to severe storms is expected to develop late in the day on Monday in western MN, tracking east toward Wisconsin through the evening.

- Long duration period of heat and humidity starts Monday. The Extreme Heat Warning remains in effect for Monday. Counties that were not initially in the Excessive Heat Warning were placed in a Heat Advisory. Heat impacts will be felt all week with little overnight relief and therefore a building heat stress.

- Daily chances for thunderstorms through next week. Storms will be capable of severe weather and torrential rain, if they are able to form.

DISCUSSION

Issued at 251 PM CDT Sun Jun 28 2026

The decaying MCS that moved across the region this morning did two things. First, brought a much needed soaking rain area-wide and two, it delayed the arrival of the tropical airmass, giving us one more day of relative comfort before the heat and humidity really push in. At 2pm, that warm from was near a Sioux City to Des Moines line and won't get up into southern MN until closer to sunset, so we did pull back several degrees on highs for today.

Tonight, this warm front will continue to push north, with scattered thunderstorms expected to develop north of the warm front. Exactly when/where this next round of storms develops is uncertain, but it looks to occur between 8pm and 10pm somewhere not far from the I-94 corridor. The greatest storm coverage is expected overnight north of I-94 from east central MN, back into northwest and west central WI. These storms will be elevated, but with MUCAPE in excess of 4000 j/kg, you can't rule out a few storms being capable of producing large hail, which is covered by the Marginal Risk in the Day 1 convective outlook.

Monday, a surface low will become occluded as it moves north across the Dakotas. This will push the warm front up into northern MN, with a very hot airmass overspreading the area. As we have been seeing much of the summer, the NBM warm bias in the 48 hour + window is slowly being corrected with time, with 100 degree highs now off the map. However, we will still see highs well into the 90s, with dewpoints uncomfortably finding their way up into the mid 70s. This will create very dangerous heat conditions Monday afternoon, with afternoon heat index values topping out in the 100 to 110 range. For heat headline changes, we added Morrison County into the Excessive Heat Warning, with any counties not in the Warning placed into a Heat Advisory. For now, we continue to run this one-day at time to see how convection influences temperatures through the rest of the week.

As for those storm chances, we will see a strong cap move in behind the warm front, with h7 temps on Monday surging to around +16C. However, as the surface low moves into southern Canada Monday afternoon, we will see a cold front push into western MN. At the same time, the upper trough driving this system will push far enough east to start nudging the EML and associated cap east as well, with h7 temps along the SD border progged to drop below 12C around 00z (7 pm Monday evening). This will set the stage for convective initiation along the cold front in western MN around that 7pm timeframe. At this juncture, we're leaning on what the AI versions of the GFS and ECMWF shows, which would say the 12z NAMnest likely has the best idea of what storms will look like later in the day on Monday. The greatest severe risk Monday is definitely up in the Red River Valley, but with MLCAPE progged to be in excess of 5000 j/kg, any storms that form down here will have the potential to be severe. Given the expected storm mode (linear) and very high freezing levels, damaging wind gusts look to be our primary risk, with a tornado or two being possible as well. The greatest severe risk Monday looks to be west of I-35, with the Day 2 Slight Risk pretty close to what our expectations are.

For the rest of the forecast through 4th of July weekend, ridging will be the dominate player. That ridge will be centered over the Tennessee Valley during the upcoming week, it will break down next weekend, then intensify over the 4-corners region after the 4th. Through all of this, the northern tier of the central CONUS will remain on the periphery of the ridge, within the zone of enhanced upper flow. A classic ring of fire pattern. The current expectation is that the front that comes in Monday night will stall out over the region as it runs into the upper ridge to the southeast. It is expected that each day next week, we'll see storms bubble up along the boundary in the late afternoon/early evening. With Pwats never far from 2" and MUCAPE always in excess 2000 j/kg, heavy rainfall and severe weather will be a daily risk, it's just a question of where the boundary and any subtle shortwaves will be on a daily basis. As of this afternoon, the front looks to likely be south of us on Tuesday, but then drift back up over us Wednesday and Thursday, when the NBM shows likely (over 55%) and even some categorical (over 75%) PoPs during the overnight hours both days. This same type of weather pattern will continue through the Fourth of July, with high confidence in daily thunderstorms occurring, but low confidence on where they will be between central Iowa and northern MN. The one bright spot of all this potential activity is that it does keep us out of the extreme category for heat, but definitely still in the uncomfortable category, with daily highs around 90, afternoon heat indices pushing 100, and lows struggling to dip much below 70 thanks to the dewpoints frequently sitting above 70.

AVIATION /18Z TAFS THROUGH 00Z TUESDAY/

Issued at 121 PM CDT Sun Jun 28 2026

This forecast period has proven to be tricky especially forecasting cigs. This morning's wake low has left enough trailing subsidence which has forced clearing across southwestern MN. Hi-res guidance has handled this subsidence poorly. It is expected that isentropic upglide should regain dominance and force scattered to broken low VFR cu to develop this afternoon. There also is another shot that our northern sites (AXN, STC, and RNH) see a few scattered showers/thunder redevelop this afternoon. Forecast soundings do prefer that the environment is capped aloft however included prob30 mentions at these sites should any cu manage to produce any precip.

As for winds, the highest wind gusts have moved east accompanied with the wake low. Conditions will remain breezy out of the SE this afternoon between 20-30kts then gradually be on the decrease this evening. Winds then will shift southerly late tonight into early tomorrow morning and increase once again with gusts between 20- 30kts.

KMSP...Scattered low VFR cu this afternoon with breezy SE'ly gusts between 25-30kts. Winds weaken this evening with cigs redeveloping. At this time, low confidence exists if MSP manages to reach MVFR cigs this evening vs. low VFR and scattered. Decided to keep the TAF in low VFR at this time but lowered sky cover could be introduced in future amendments based on trends. Kept precip mentions out of MSP for now as higher confidence for any redevelopment of precip was north of the field. Winds shift southerly tonight and increase back to 25-30kts late morning/early afternoon.

/OUTLOOK FOR KMSP/ MON...VFR. Chc PM TSRA. Wind S 15-20G30 kts. TUE...VFR. Wind SW 10-15G25 kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...Heat Advisory from 9 AM Monday to midnight CDT Monday night for Chippewa-Douglas-Lac Qui Parle-Pope-Stevens-Swift- Todd-Yellow Medicine. Extreme Heat Warning from 9 AM Monday to midnight CDT Monday night for Anoka-Benton-Blue Earth-Brown-Carver-Chisago- Dakota-Faribault-Freeborn-Goodhue-Hennepin-Isanti-Kanabec- Kandiyohi-Le Sueur-Martin-McLeod-Meeker-Mille Lacs- Morrison-Nicollet-Ramsey-Redwood-Renville-Rice-Scott- Sherburne-Sibley-Stearns-Steele-Waseca-Washington- Watonwan-Wright. WI...Heat Advisory from 9 AM Monday to midnight CDT Monday night for Rusk. Extreme Heat Warning from 9 AM Monday to midnight CDT Monday night for Barron-Chippewa-Dunn-Eau Claire-Pepin-Pierce- Polk-St. Croix.