textproduct: Sioux Falls

KEY MESSAGES

- Heat indices will continue to approach the upper 90s through Tuesday. Make sure to stay hydrated!

- Isolated strong to severe storms will be possible this evening in areas along and north of I-90. 60 mph winds and quarter sized hail will be the greatest risks.

- Scattered severe storms capable of quarter size hail and 60 mph winds will again be possible from late Tuesday afternoon into early Wednesday.

- Temperatures will rise towards the middle 90s to 100 degree mark by next weekend.

DISCUSSION

Issued at 230 PM CDT Mon Jul 6 2026

CURRENTS & TONIGHT: Taking a look across the area, we're continuing to watch a broken line of scattered showers with isolated thunderstorms progress across western and central SD this afternoon mainly in response to the approaching cold front. With a small cap in place aloft according to soundings, the general expectation is for this activity to gradually weaken upon approach. However, as diurnal heating persist and eventually erodes the rest of the cap; short-range guidance continues to show additional convection developing with the cold front this evening initially across northeastern SD and potentially southcentral SD. Both areas of convection will likely meet in our area during the late evening to early overnight hours mainly along and north of I-90 with the main hazards being up to quarter-sized hail and strong wind gusts up to 60 mph. Otherwise, should see this activity gradually weaken past the I-90 corridor as instability wanes with the loss of diurnal heating. Lastly, expected another warm night with lows mainly in the upper 60s to low 70s.

TUESDAY-THURSDAY: Looking into Tuesday, quieter conditions will return for the first half of the day as quasi-zonal flow continues aloft. With similar conditions to today in place, expect another dose of the summer heat as highs to peak in the upper 80s to upper 90s for most areas with heat indices in the low to upper 90s. With this in mind, make sure to stay hydrated and to take frequent breaks when working outdoors. Otherwise, the main focus continues to be the severe weather potential from late Tuesday into Wednesday. Looking aloft, we're still on track for scattered showers and thunderstorms to track from central SD through areas along and north of I-90 with the surface front during the evening to overnight hours. However, the main question continues to be how does this developing activity evolve during this time and will it be severe. With the better forcing continuing to sit closer to the ND/SD border, we'll continue to hedge our bets on the better severe risk being north of us.

However, still can't completely rule a few isolated gusts up to 60 mph north of I-90 if strong cold pools can develop with a few weakening thunderstorms. Otherwise, gradual weakening should continue through Wednesday morning as this activity progresses southeastwards with the surface front into a more stable environment. Slight cooler conditions will be possible by Wednesday as cooler air funnels in behind the previously mentioned boundary leading to highs mainly in the 80s to low 90s. Additional showers and thunderstorms could develop along/ahead of the boundary by Wednesday afternoon mainly across northwestern IA and the lower Missouri River Valley. While an isolated severe risk can't be ruled out mainly across the Highway-20 corridor and portion of northwestern IA, the location will be highly dependent on where the surface boundary ends up setting up during the afternoon. Lastly, mostly quiet conditions should return by Thursday as highs slightly decrease into the low to upper 80s for the day.

THE WEEKEND: Heading into the extended period, an active period will continue aloft as quasi-zonal flow continues into the weekend. Multiple waves will progress through the plains leading to at least some smaller chances (<30%) through Saturday. With the ridging expected to strengthen over the western CONUS during the upcoming weekend, we could see the return of oppressive temperatures mainly in the 90s to low 100s as early as Sunday. With heat indices potentially reflecting similar values, make sure to stay hydrated and to monitor your local forecast!

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1230 PM CDT Mon Jul 6 2026

Mainly VFR conditions with occasional MVFR vsbys will be possible this TAF period. Taking a look at satellite imagery, we're starting to see a cumulus field spread westwards this afternoon. We're still on track for isolated showers and storms this evening and tonight mainly north of I-90. With growing confidence in storms, decided to add a TEMPO group to KHON since thats where most guidance is keying on. Also added a PROB30 group to KFSD just in cast weakening storms lingering into the I-90 corridor. Otherwise, marginally breezy southerly winds will continue into the evening before lightening up to end the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None. IA...None. NE...None.