textproduct: Sioux Falls

KEY MESSAGES

- One more day of seasonable late-July temperatures today.

- Summer heat returns this weekend with multiple days of highs in the 90s to around 100, warmest toward central SD. Heat related headlines may be needed.

- While details are uncertain, if storms develop Sunday evening into Sunday night, some may be strong to severe with damaging winds, isolated large hail and heavy rain possible.

UPDATE

Issued at 415 AM CDT Fri Jul 24 2026

If you are not a fan of heat/humidity, be sure to enjoy today before the heat returns this weekend. Confidence is fairly high that highs in the 90s to around 100 will return for Saturday and Sunday, with warmest readings most likely toward central South Dakota. The questions come in just how high temperatures and/or dew points will get. For that reason we have opted to hold off on any heat headlines for now and will give the day shift another look at low level thermal profiles and coverage of upper level smoke which could hold temperatures down a bit from model output if it is thick enough.

With the building heat, storm chances are generally on the low side through the weekend. However, will have to watch a couple of periods for a possible increase in rain chances. First will be toward central South Dakota late Saturday. Forcing is weak, as is deep layer shear, but several CAMs are hinting at spotty storms developing as this area heats out, which could potential drift into our western counties. There is currently a Level 1 of 5 (Marginal) risk for severe storms just west of our CWA in the Day 2 outlook, but if these storms are able to grow upscale as seen in some of the high-res output, this risk area may need to be expanded for an isolated damaging wind threat. Confidence in this potential is low at this time.

A second period of concern would come Sunday evening into the overnight hours, as detailed in the Day 3 SPC outlook which bring a Marginal to Slight (Level 1 and 2 out of 5) risk across the eastern half of the forecast area. Once again, details are low confidence as the risk is conditional on storms developing as a wave and associated boundary move through the Dakotas and Minnesota. Damaging winds would again be the primary threat, but large hail and heavy rain are also possible.

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 SATURDAY/

Issued at 1209 PM CDT Fri Jul 24 2026

IFR to MVFR conditions will slowly improve through mid afternoon. Additional stratus and fog may develop later tonight into Saturday morning with the better chances in northwest IA, northeast NE and far southeast SD.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Heat Advisory from noon Saturday to 8 PM CDT Sunday for SDZ038>040-050-052>071. MN...Heat Advisory from noon Saturday to 8 PM CDT Sunday for MNZ071- 072-080-081-089-090-097-098. IA...Heat Advisory from noon Saturday to 8 PM CDT Sunday for IAZ001>003-012>014-020>022-031-032. NE...Heat Advisory from noon Saturday to 8 PM CDT Sunday for NEZ013- 014.