textproduct: Sioux Falls

KEY MESSAGES

- A few funnels will be possible through early evening mainly near and east of I-29.

- Isolated to scattered thunderstorms will develop this evening mainly east of I-29 and potentially along the Missouri River Valley. A few storms could become severe with large hail up to quarter sized and damaging wind gusts up to 60 mph being the main threats.

- Pockets of fog will be possible overnight. Locally dense patches could lead to visibility as low as 1 mile or less at times.

- Near to above normal temperatures will continue into the new week with highs mainly in the 80s to mid 90s.

DISCUSSION

Issued at 238 PM CDT Sat Jul 4 2026

CURRENTS & TONIGHT: Taking a look across the area, the focus continues to be across portions of northwestern IA as a lifting outflow boundary continues to spur pockets of convection across portions of northwestern IA. While this developing activity continues to stay mostly sub-severe, the enhanced stretching potential and weak flow aloft has led to multiple funnels being reported mainly near Greenville and Sioux Rapids, IA in Clay County. With this developing activity potentially continuing over the next few hours have decided to issue a special weather statement (SPS) for most of northwestern IA, portions of southwestern MN, and portions of southeastern SD through 5 PM.

Otherwise, we're still on track for a few additional isolated to scattered thunderstorms with an approaching wave this evening. Given the modest CAPE and low shear set up, there is still a decent shot for a few stronger storms with up to half dollar sized hail and damaging winds up to 60 mph being the main threats. While there is still some uncertainty as to how things will evolve, most short- range guidance has now settled in on areas east of I-29 and along the Missouri River Valley as the two areas for potential development through the late evening so make sure to have multiple ways to receive warning information! Lastly, can't rule out some additional chances for patchy fog tonight with the higher dew points. Similar to this morning, locally dense patches could lead to visibilities of 1 mile or less at times through mid-morning before dissipating.

SUNDAY-TUESDAY: Looking into Sunday, quieter conditions will temporarily return as ridging begins to build across the Desert Southwest. With weaker flow aloft and increasing warm air advection (WAA), should continue to see temperatures trend above normal through Tuesday with highs mainly in the 80s to 90s each day. Looking aloft, our next precipitation chances could arrive as early as Monday night into Tuesday as an approaching shortwave intersects a stalled surface boundary roughly draped from the Black Hills to northeastern SD. While there is still some uncertainty as to how far east this boundary sets up, there should be just enough lift with the wave to trigger a few scattered showers and thunderstorms during the afternoon to evening hours with the potential for a few stronger storms. Given another modest CAPE/low shear environment, any developing activity will be quite pulsy. However, current thoughts are an isolated severe risk will be possible mainly along and south U.S. Highway-14 heading into the afternoon and evening hours. Otherwise, additional chances for showers and thunderstorms will return from Tuesday into into Wednesday as another shortwave and an a cold front progress through the area. However, some uncertainty remain so make sure to monitor your local forecast as the details are subject to change.

WEDNESDAY-FRIDAY: Heading into the extended period, the previously mentioned ridging begins to flatten giving way to quasi-zonal flow by Wednesday. With the wave train expected to resume aloft, we could see near daily chances for precipitation through Friday. While the severity of these storms is still uncertain, confidence is not high enough to deviate from the NBM at this time. Otherwise, we'll continue to see near to above normal temperatures through Friday with highs mainly in the 80s to low 90s.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 637 PM CDT Sat Jul 4 2026

Isolated showers and thunderstorms will continue to be possible through the evening, though low confidence on which areas get hit with a storm. Enough signs in and around KFSD that one or two thunderstorms will develop near the area, so added a PROB30 group there through 05.04Z this evening to account for this. Storms in northern South Dakota are moving southward, but look to miss KHON to the west or weaken before arriving, but trends will be monitored.

Patchy fog may develop late tonight/early tomorrow morning, with guidance favoring areas east of I-29 for the best potential. Not enough confidence in fog development at the TAF sites, so will leave out mention at this time. Otherwise, VFR conditions will take us into the daytime Sunday. Light and variable winds are expected through most of the period, with east-southeasterly winds increasing slightly to end the period mainly near and west of the James River.

FSD WATCHES/WARNINGS/ADVISORIES

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