textproduct: Sioux Falls

KEY MESSAGES

- Localized fog will continue mainly in our waterways and low laying areas through mid-morning.

- Temperature will continue to trend near to above normal into the weekend with highs mainly in the 80s to low 90s.

- Besides some smaller periodic rain chances (20% or less), mostly dry conditions are expected through Sunday.

UPDATE

Issued at 436 AM CDT Wed Aug 5 2026

Taking a look across the area, conditions continue to clear this morning as a surface high moves in overhead. With lighter surface winds in place, we've started to see patchy areas of fog develop mainly along our waterways and in low lying areas. While we're not expecting any widespread coverage, can't rule a few locally dense patches mainly across northwestern IA with the potential for visibility as low as a mile or less through mid-morning. Otherwise, we're still on track for dry and quiet conditions today as highs peak in the upper 70s to low 80s for the day. Lastly, wildfire smoke will continue to sit over most areas aloft with limited surface impacts.

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 /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 642 AM CDT Wed Aug 5 2026

Mostly VFR conditions continue across the area with occasional MVFR to LIFR vsbys mainly due to developing fog. While this is mostly confined to our River Valleys, should see the fog persist through 14z-15z (9am-10am) before gradually dissipating. From here, mainly VFR conditions should persist across the area. Otherwise, light and variable surface winds will continue across the area with a surface high overhead to end the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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