textproduct: Sioux Falls

KEY MESSAGES

- Scattered showers with isolated thunderstorms will return starting this afternoon and continue into the overnight hours. Severe weather is not expected.

- Strong northwest winds by Wednesday will bring the return of gusts between 40-50 mph. With additional scattered showers with isolated thunderstorms possible by Wednesday afternoon, could see an additional strong wind threat.

UPDATE

Issued at 358 AM CDT Tue Jun 16 2026

Taking a look across the area, mostly clear conditions continue tonight as temperatures continue to fall into the upper 40s to low 50s. Depending on if winds can get light enough, could get some patchy River Valley fog to develop mainly along portions of the James and Missouri River Valleys. While the fog won't last long, can't rule out some brief visibility reductions on those morning commutes. Otherwise, quieter conditions will continue into the early afternoon with highs peaking in the low 70s to mid 80s for the day.

Looking aloft, we're still on track for scattered showers with isolated thunderstorms to develop this evening as an approaching shortwave and warm front progress through the area on the nose of an upper-level jet streak. Given the high shear/low CAPE environment, severe weather is not expected. However, pockets of moderate rainfall along with an occasional stroke of lightning will be possible with any stronger activity that develops into the overnight hours. The strongest activity will likely be focused along and north of a Huron to Sioux Falls to Spencer line. Nonetheless, we could see light returns across most of the county warning area (CWA) through daybreak on Wednesday.

No significant changes to Wednesday onward; see below for details.

DISCUSSION

Issued at 1257 PM CDT Mon Jun 15 2026

Model soundings and the latest hi-res models continue to indicate the potential for strong wind gusts with any shower and thunderstorm activity that develops this afternoon and evening. These wind gusts will be tied to surface based instability of about 200-500 J/kg. Given the diurnal nature of this activity, the best chance for the strong wind gusts will be roughly 4 pm to 9 pm. Only very isolated activity will linger through about 10 pm to midnight. Otherwise a little patchy fog will be possible around the Kingsbury and Brookings county areas late tonight and early Tuesday morning.

An unseasonably strong jet max will dive southeast Tuesday into Wednesday. As this jet max moves into the area Tuesday, warm advection will increase with the chances for showers and isolated thunderstorms arriving possibly during the afternoon, but the better chances will be at night. While forcing is fairly strong, instability is lacking due to a fairly deep dry layer in the lower levels. However, with the EML running around 7.5 C and some decent forcing, showers and isolated thunderstorms will be possible with this shot of lift. The better chances appear to be near and northeast of a Huron to Spencer IA line with the best chances in southwest MN.

This almost spring or fall like system will bring strong surface winds to the area Wednesday. Gusts of 45 to 50 mph will be likely during the day as mixing brings down some very strong winds aloft. The latest models show a 130 knot jet around 300 mb, with unidirectional flow from the west northwest throughout the atmosphere. While we will have a small convective threat on Wednesday afternoon and evening, model soundings indicate weaker instability than today, but still some 100-300 J/kg surface based CAPE mainly north of I-90. With the strong, unidirectional winds, wind gusts around 50 mph with these showers will be possible.

Broad troughiness moves through Thursday and should bring quieter weather and seasonably cool conditions.

Weak upper level ridging builds on Friday and will keep quiet weather in place with temperatures back into the upper 70s to mid 80s.

Saturday will see a system pass by, possibly a bit to the south. However this will be the next better chance for showers and storms with isolated severe storms possible. Something worth keeping an eye on.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 632 AM CDT Tue Jun 16 2026

Mainly VFR conditions will continue this TAF period. Quieter conditions will continue through midday. Scattered showers will gradually become more widespread into the evening. Added in MVFR PROB30 groups for both KFSD & KHON since that's where the highest confidence is. Carried prevailing VFR -SHRA into KSUX since they're on the edge. Otherwise, light northwesterly winds will become more southerly heading into the overnight hours to end the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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