textproduct: Sioux Falls

KEY MESSAGES

- Light to moderate showers will progress through areas along and south of I-90 as early as this afternoon. Accumulations of a 0.25" to 0.50" of an inch will be possible near and just north of the Missouri River Valley.

- Below normal temperatures expected through Friday, then summer heat returns over the weekend with multiple days of highs in the 90s to possibly low 100s ahead. Heat-related headlines may be needed.

DISCUSSION

Issued at 148 PM CDT Thu Jul 23 2026

An upper level wave and saturation aloft will move through the area later this afternoon through tonight. While some very weak instability is expected aloft, thunder is very unlikely. Saturation aloft is most prominent between I-90 and the Missouri River and with the dry layer in the low levels not excessively dry, some quarter to possibly half inch rainfall amounts are possible over about a 6 hour period.

Friday should generally be dry and mild, maybe a few showers in northwest IA during the morning. Highs remain below normal, but will be a bit higher with most locations climbing into the 80s, coolest in northwest IA.

Hot conditions return for the weekend into early next week. The latest bias corrected data is running about 5 degrees cooler than the model output for Saturday through Monday. Will have to keep an eye on trends as the heat approaches as last weeks warm up the NBM overdid the heat almost every day. This time around there will be a better potential for southwest winds at the surface which generally aids in heating out, so maybe the 3-6 degree warm bias that was seen with the past warm up will be a little less. Long story short, the bias corrected output falls just short of a heat advisory both Saturday and Sunday while the NBM is basically in heat advisory both days.

Convective chances are pretty small through Monday. A slightly stronger wave will drop south on Sunday and bring a small threat for severe storms. The better chance should be north and east of the area. This will be the main time frame to track over the upcoming days.

Tuesday through Thursday should see upper level ridging just west of the area with stronger northwest flow aloft just northeast of the area. This leaves the area in position for above normal temperatures, but possibly not on the excessive side as weak waves will at times allow slightly cooler air to move in. With these weak waves will come periodic chance for showers and thunderstorms but for now confidence in this activity is low.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1206 PM CDT Thu Jul 23 2026

An area of showers will move through later this afternoon through tonight. The better chances will be near and south of I-90. During and after the rain tonight, MVFR and possibly IFR ceilings are expected, which should improve back to VFR in most locations by the end of the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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