textproduct: Twin Cities

KEY MESSAGES

- Severe thunderstorms possible late Thursday afternoon & evening.

- Heat & humidity return for Friday into the weekend. Heat Index values around 100 degrees likely.

- Frequent chances for scattered showers & thunderstorms into next week.

DISCUSSION

Issued at 226 PM CDT Wed Sep 2 2026

Tonight: Quiet weather tonight with cloud cover beginning to increase overnight. Patchy fog is possible across southern Minnesota where 1-2: of rain fell last night, most pronounced in valleys & other low-lying areas.

Thursday Morning: A low-level jet over the central plains strengthens overnight, nosing into southern Minnesota & southwest Wisconsin by early tomorrow morning. Scattered showers & thunderstorms are expected to develop on the nose of this jet, with the best chance for some rain expected from southern Minnesota into western Wisconsin. Sporadic wind gusts of 30-40 mph & small hail can't be ruled out with the strongest of these thunderstorms, but the threat for any strong thunderstorms is higher off to our south. High-resolution models still remain widely varied in depicting how theses showers & storms will evolve into tomorrow morning, so confidence remains low on forecasting just how widespread the rain will be & how long it may linger into Thursday morning.

Thursday afternoon/evening: The answer to the above question will play a large role on what kind of potential may develop for thunderstorms later Thursday afternoon & evening. Synoptically, an impressive environment for severe weather will develop over the upper Midwest Thursday as an upper level jet with 50 kts of deep shear develops long the northern tier of the CONUS, while an elevated mixed layer advecting from over the Rockies provides very steep lapse rates around 8 C/km. However we won't have much of surface boundary over the area to initiate storms, so our severe potential will depend greatly on how much instability we can realize by the afternoon. Warm & moist advection through the day will provide the conditions for CAPE values to reach 3000-4000 J/kg - if we're able to remain sunny through the afternoon & warm into the upper 80s to low 90s. It's no surprise that the same high- resolution modes that remain widely varied regarding the showers & thunderstorms tomorrow morning & also widely varied with how they depict the second round of thunderstorms during the afternoon/evening. Generally, the wetter/cloudier solutions hold off any thunderstorms until later in the night when a potential MCS could arrive out of the Dakotas, while the drier solutions are able to develop some discrete storms over central & southern Minnesota by late afternoon.

Confidence is low, but the general trend seems to be towards the showers & cloud cover lingering longer into the morning & afternoon. This does not mean we're done with a severe threat tomorrow evening though, as there are signs that thunderstorms developing closer tot he surface low over the dakotas could congeal into a MCS that eventually propagates through the area later in the evening & night. Damaging wind will be the primary severe threat with any storms that develop, especially if we get the forward-prooapgating MCS out of the Dakotas, while very large hail is possible earlier in the evening with any discrete storms that develop over central/southern Minnesota. Heavy downpours are expected with thunderstorms but they should be moving fast enough to mitigate any heavy rain/flooding concerns.

Friday-This Weekend: Warm advection continues into the weekend with a return to more summer like humidity values, along with temperatures in the upper 80s to low 90s. Excessive heat could become a concerns as Heat Index values approach 100 degrees, but we are still coming off of a very warm July-August so acclimation means we're probably able to push our excessive heat thresholds a little higher than normal. Friday looks to be dry but another chance for isolated to scattered thunderstorms looks likely overnight into early saturday morning. Models remain widely spread in possible precipitation events through the rest of the weekend, so even though our forecast shows 30-40% PoPs, it won't be a washout of a weekend.

Next Week: The upper air pattern remains active as a number of disturbances ride over the ridge centered over the region. Confidence is low on when & where the greatest precipitation chances will be, but there at least appears to be some minor relief coming from our drought. temperatures will depend on the timing of any precipitation systems, but will tend to be above- normal earlier in the week with some cooling relief likely later in the week.

AVIATION /06Z TAFS THROUGH 12Z FRIDAY/

Issued at 122 AM CDT Thu Sep 3 2026

Few to sct VFR clouds will continue to move east-northeast early this morning. Warm advective -SHRA/-TSRA has already developed along the MN/IA border and will lift northward over the next several hours. For MKT and RWF, have upgraded SHRA mentions to TSRA given latest forecast trends. Timing for this round of precip remains between 11 to 18z with MKT (~11s arrival) being the earliest and RNH/EAU being the latest (~15z arrival). The forecast technically calls second round of afternoon. However, feeling uncertain how this morning's convection may lower chances later in the day. Thus have only included a later round of MVFR prob30s for TSRA at STC, RNH, and EAU. Light winds with and easterly component become southerly by late morning with a few gusts between 18-20kts, before shifting back to the east this evening.

KMSP...Maintained the prob30 for -SHRA this morning between 14 to 17z. Instability will exist aloft for thunder however unsure if t- storms reach the field directly or move south similar to yesterday morning. Southeasterly winds shift to southerly by late morning with a few gusts nearing 18-20kts before shifting easterly after 00z.

/OUTLOOK FOR KMSP/ FRI...VFR. Wind S 5-10 kts. SAT...VFR. Chance -TSRA late. Wind SE 5-10 kts. SUN...VFR. Chance -TSRA. Wind SSE 5-10 kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None.