textproduct: Sioux Falls

KEY MESSAGES

- Showers and very isolated thunderstorms will diminish and shift southeast later this afternoon into this evening. Rainfall amounts generally less than a quarter of an inch.

- Milder temperatures through Wednesday with above normal temperatures Friday into the weekend. Although details are uncertain, showers and thunderstorms may return to the region this weekend.

DISCUSSION

Issued at 124 PM CDT Tue Aug 4 2026

A weak trough with mid level moisture and weak elevated instability will exit by about early evening, which will end the showers and thunderstorms across the area. Behind this wave skies will clear a bit and with light wind some fairly chilly morning lows are expected. Expect lows in most locations from the upper 40s to mid 50s. With lighter winds and clear skies some patchy low land fog will be possible.

Low pressure moves along the Canadian border on Thursday, with a trailing trough expected to move through the area Thursday night. For now the atmosphere looks a little too dry for much in the way of showers or thunderstorms, so will keep chances at 20 percent or less.

Friday is a tough call as instability increases across the area, but capping looks to limit the convective potential. Also of note is some disagreement on timing of the weak wave moving through Thursday night. If the faster runs are more accurate, then capping is likely to be even more difficult to overcome. A slower trough could allow for a little additional heating which would support a few thunderstorms.

Models continue to point towards faster westerly flow aloft Saturday and Sunday which may bring some scattered showers and thunderstorms to the area this weekend. Currently looking like Sunday night will be the better chance for showers and storms.

Upper level flow will turn light northerly early next week which will bring temperatures back to below normal with limited chances for precipitation.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1205 PM CDT Tue Aug 4 2026

Showers and isolated thunderstorms will continue mainly south of I-90 through early evening. Very brief MVFR conditions will be possible within this activity. Outside of any showers and storms VFR conditions are expected. With light winds and mostly clear skies later tonight, some very patchy low land fog will be possible.

FSD WATCHES/WARNINGS/ADVISORIES

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