textproduct: Sioux Falls

KEY MESSAGES

- Scattered showers are likely late afternoon through about sunset. While severe weather is not expected, an occasional stroke of lightning and strong wind gusts of 45 to 55 mph will be possible. The better chances will be near and north of I-90. - A band of showers and isolated thunderstorms are likely Tuesday evening and night, with the better chances northeast of a Huron to Spencer IA line. Severe weather is not expected.

- Wednesday will be windy as a Spring-like system moves through. Gusts of 45 to 50 mph are likely. Scattered afternoon and evening showers may also bring additional wind threats.

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 /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1150 AM CDT Mon Jun 15 2026

Scattered showers and very isolated thunderstorms are expected from about 4 pm to 9 pm today. The main threat will be wind gusts of 40 to 50 mph. Otherwise outside of any showers and storms, VFR conditions are expected.

FSD WATCHES/WARNINGS/ADVISORIES

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