textproduct: Sioux Falls

KEY MESSAGES

- Warmer and more humid air returns Friday through the weekend with moderate (40-60%) chances for storms late Friday into Friday night.

- Periodic shower and storm chances continue this weekend into early next week. Confidence on any details is low.

- Temperatures will be above normal this weekend into the middle of next week. Highs likely in the 90s Saturday and possibly Sunday.

UPDATE

Issued at 840 PM CDT Wed Aug 26 2026

Taking a look across the area, mostly clear and quiet conditions persist this evening with a surface high firmly overhead. Expect these conditions to continue into Thursday morning as lows touch the mid to upper 50s for the night. Otherwise, the forecast remains on track with another mostly quiet day ahead with highs peak in the low to upper 80s. Any precipitation chances should be fairly limited mainly due to the increased subsidence with the associated upper- level ridging and bone dry sounding profiles. However, can't completely rule out a very low chance (<10%) for some isolated sprinkles across portions of southcentral SD as pieces of weak lift "ride the ridge" into the area. Nonetheless, any accumulations would be limited (if any). Lastly, confidence continues to increase in the return of showers and thunderstorm over the weekend with the first chances (50%-70%) from Friday night into Saturday. However, some uncertainty remains on the exact location of initial development. With this in mind, make sure to monitor your local forecast especially if you have any upcoming outdoor plans.

DISCUSSION

Issued at 108 PM CDT Wed Aug 26 2026

Surface high pressure remains in place through Thursday resulting in quiet weather across the area. Lows in the 50s tonight with highs on Thursday in the lower to mid 80s.

Elevated moisture moves in around the 700-800 mb layer late Thursday night into Friday morning. This could result in spotty showers and isolated thunderstorms. Shear is weak and CAPE values running about 500-1000 J/kg. Very defendant upon this small layer of moisture however, so confidence is low for now.

Southerly flow become established at the surface on Friday with gusts around 25 to 30 mph likely. With south to southeast flow at the surface any instability that develops through the day will likely remain capped, however with some potential for a wave to move through on Friday afternoon this capping could weaken and allow a few thunderstorms to develop. With moderate shear and 1000-1500 J/kg CAPE, an isolated severe storm will be possible. A secondary wave and slightly deeper instability on Friday night may lead to additional shower and thunderstorm chances with additional severe weather threats.

Temperatures warm across the area on Saturday as the wave moves by to the north. Even with stronger west southwest flow aloft and decent mid level warm advection, weak mid to upper level ridging should suppress any convective activity. Highs should climb into the 90s near and west of I-90.

Sunday may be a day to keep an eye on we a wave tracks by along the Canadian border and a weaker sub tropical like wave drifts northeast into the area. With another day expected to climb into the 90s and some weak forcing aloft, we could see a few storms develop. For now confidence is too low to include in the forecast.

Southwest flow aloft remains in place through the middle of next week and the next wave of interest has some agreement and may arrive Monday night into Tuesday. Otherwise temperatures will remain above normal Monday int Wednesday.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 615 PM CDT Wed Aug 26 2026

VFR conditions will continue this TAF period. Besides a dissipating cumulus field this evening, expect mainly lighter winds through Thursday afternoon. Can't rule out some patchy fog overnight mainly in along our waterways and a few low spots. However, confidence isn't high enough to add it into the TAFs at this time so kept the mention out.

FSD WATCHES/WARNINGS/ADVISORIES

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