textproduct: Twin Cities

KEY MESSAGES

- Thunderstorms likely Wednesday morning with a risk for severe wind and hail.

- A second round of storms is expected Wednesday evening, with a level 3/5 risk for severe weather. Winds of 70+ mph possible, along with large hail and a few tornadoes.

- Storms and humidity continue through the weekend, with localized flash flooding possible for areas that see multiple rounds of storms.

UPDATE

Issued at 408 PM CDT Tue Jun 30 2026

A conditional risk for severe storms has developed this afternoon along the stalled boundary where roughly 3000-4000 J/kg of MUCAPE overlap 35-40 kts of effective bulk shear. Most storms have struggled to fully organize so far, and with limited forcing for ascent, it is likely that anything severe will be more isolated than not. The primary hazards are damaging wind and hail, but a tornado cannot be ruled out. A Severe Thunderstorm Watch has been issued to highlight this risk through 10pm tonight.

DISCUSSION

Issued at 332 PM CDT Tue Jun 30 2026

Visible satellite imagery shows an occluded low spinning over southern Manitoba, with a slow moving cold front extending down from Lake Superior through western WI and into northern IA. Despite having this front move through, temperatures are still warm with widespread 80s and even some spots hitting 90 already this afternoon across eastern MN and western WI. It is not as humid today for areas behind the front, but many locations are still seeing upper 60s or low 70s closer to and ahead of the front. A Heat Advisory remains in effect through 9pm for these locations, with heat indices maxing out around 95-100 degrees.

The front becomes quasi-stationary as it slowly drifts north from Iowa tomorrow. This will shift winds more S/SE-erly and increase moisture transport through the day. PWATs are expected to climb to 1.5-2" by Wednesday evening, setting the stage for more humid conditions to continue throughout the week. Along this boundary and moisture influx, multiple rounds of storms are expected, starting early tomorrow morning. A northeastward propagating MCS is expected to develop along the nose of a strengthening LLJ across Nebraska this evening, which should continue all the way into southern MN and potentially western WI. Adequate shear and instability will be present to support organized convection with a damaging wind and hail risk. Forcing does weaken during the early morning as the storms move into southern MN, so this may limit the overall coverage and risk of severe weather. The most likely timing is between 5-8am for much of MN and between 8-10am for western WI. These storms will be moving quickly, so we are expecting to clear out for the most part by late morning. Filtered sunshine will warm us up into the 80s and allow the atmosphere to destabilize again during the afternoon.

There is growing confidence for a second round of storms to develop along the stationary boundary during the late afternoon into the early evening. Thermo profiles would support both large hail and damaging winds, especially if storms are able to remain discrete during initialization. We expect storm to cluster together as the event unfolds, potentially maturing into a bowing MCS. In this scenario, the damaging wind threat would increase with winds of 70+ mph becoming possible. Storms may not develop until early evening across southwest MN (around 6-8pm) and then may not exit east until late in the night (around 1-2am). The latest SPC Day 2 SWO has been upgraded to a level 3/5 (Enhanced) risk for time period, with an emphasis on a risk for those elevated wind speeds depending on storm mode. This remains a situation where the morning convection will play a role on how the storm threat evolves in the evening, primarily in influencing where the surface boundary sets up.

Storms and humid conditions continue through the week as this quasi-stationary front acts as a fire hose for convection to fire along. WPC's latest 5-day QPF places a broad footprint of 2"+ for much of the southern half of MN and the majority of WI, as well as a bullseye of 5"+ for southeastern MN. As it always does with summertime convection, total rainfall will likely be more sporadic than this forecast, but this highlights the idea that we will continue to have several rounds of storms over a somewhat confined area as long as the boundary does not shift that much over the next few days.

AVIATION /00Z TAFS THROUGH 06Z THURSDAY/

Issued at 705 PM CDT Tue Jun 30 2026

No concerns in the immediate term, but showers and thunderstorms are expected to develop overnight across Nebraska/South Dakota and move into southern Minnesota and western Wisconsin. Northward extent of this TSRA is somewhat uncertain, but have converted PROB30s to TEMPOs/prevailing for all but KAXN/KSTC. The most likely window for convection is 10z-16z from southwest to northeast.

There should be a return to VFR conditions during the late morning and early afternoon before another potential round of storms develops. The confidence in this round is low due to uncertainty in how things recover following morning storms, but have introduced PROB30s for the end of the period.

KMSP...Added in prevailing showers beginning at 11z, but kept things VFR with a TEMPO for IFR between 12-15z. Hopefully this window can be narrowed down with the next TAF issuance. Winds are south-southwesterly through the period with gusts of around 20kts returning during the afternoon. As mentioned above, lots of uncertainty regarding the second round of storms with a wide range of hi-res model solutions as far as timing goes. As such, have a lengthy PROB30 through tomorrow evening.

/OUTLOOK FOR KMSP/ THU...VFR. Chc PM MVFR/-TSRA. Winds S 5-10kts. FRI...VFR. Chc -TSRA. Winds VRB 5-10kts. SAT...VFR. Chc -TSRA. Winds SE 5-10kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...Heat Advisory until 9 PM CDT this evening for Anoka-Blue Earth- Brown-Carver-Chisago-Dakota-Faribault-Freeborn-Goodhue- Hennepin-Le Sueur-Martin-McLeod-Nicollet-Ramsey-Rice- Scott-Sibley-Steele-Waseca-Washington-Watonwan-Wright. WI...Heat Advisory until 9 PM CDT this evening for Barron-Chippewa- Dunn-Eau Claire-Pepin-Pierce-Polk-Rusk-St. Croix.