textproduct: Sioux Falls

KEY MESSAGES

- Mainly light rain will continue to gradually taper off from west to east through this evening, with the last of the rain exiting northwest Iowa between 10 pm and midnight.

- Northerly winds will gust to around 35 mph at times today mainly east of I-29, locally up to 45 mph over parts of northwest Iowa through about 7/8 pm.

- Dry conditions and seasonable temperatures return for the weekend. For next week, shower and storms chances will return Monday night into Tuesday.

DISCUSSION

Issued at 247 PM CDT Fri Jul 31 2026

A nearly stacked low pressure system will continue to drift southeastward into central Iowa through the remainder of the afternoon, and with the surface low deepening, look for winds to increase a bit more mainly east of I-29 through the early evening hours. Most spots top out with wind gusts between 35 and 40 mph, but isolated pockets of gusts to around 45 mph will be possible over northwest Iowa through about 7 to 8 pm this evening. This should remain in short duration and isolated and so decided against wind headlines. Moisture also continues to wrap around this low which will keep mainly light rain in the forecast through this evening primarily east of I-29. Soundings show a little bit of elevated instability over parts of northwest Iowa, so can't rule out a rumble of thunder this afternoon, but chances for this are looking less and less likely. The last of the showers should exit northwest Iowa by 10 pm to midnight tonight, leading to dry conditions heading into the weekend.

Patchy fog is possible where winds can go very light to calm by early tomorrow morning, but it does look like winds should remain elevated enough to prevent widespread development. Trends will be monitored. Otherwise, a pleasant day is in store for tomorrow with highs in the upper 70s to lower 80s with dew points down into the mid 50s west to low 60s east. These lower dew points will lead to more comfortable conditions out there especially when compared to the past few days. The humidity relief will be short-lived however, as southerly flow returns on Sunday and allows dew points to rise through the 60s and potentially as high as the lower 70s in the afternoon. It won't be nearly as hot as it has been though as highs will still remain mainly in the 80s with a few pockets of highs near 90 in south-central South Dakota. Those hotter areas will likely be offset from the higher dew points though, so heat indices won't get too high. Temperatures will continue to warm on Monday and this will be out ahead of our next cold frontal passage. This cold front may bring a chance of stronger thunderstorms to the area, but the overnight timing of the frontal passage and the fact the better upper level support will be displaced to our north leads to a low confidence forecast for severe weather.

This frontal boundary may stall out or slow down near or south of the Highway 20 corridor as a large upper wave pivots slowly across the region. This will keep rain and storm chances in the forecast mainly south of I-90 through the day on Tuesday and potentially into Wednesday as well depending on where the frontal boundary stalls. Will have to watch this for perhaps some heavy rain potential as some of the lower resolution global models such as the 31.12Z ECMWF and Canadian model 48 hour QPF already shows a stripe of 1 to 3+ inches either near Highway 20 or near I-80 depending on the model. So we'll see what the higher resolution models come up with as we get closer, but these areas south of I-90 didn't receive as much rain with this most recent system, so the flood threat may still remain low anyway. Cooler weather immediately follows the cold frontal passage, with highs likely only staying in the 70s Tuesday and Wednesday before gradually warming up through the end of next week.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 622 PM CDT Fri Jul 31 2026

Scattered VFR and MVFR conditions this afternoon as a low pressure system slowly moves off to the east. Lower ceilings due to cloud cover are present mostly along I-29 and east. Ceilings are expected to gradually improve through the rest of this evening, then remain VFR for the duration.

Winds are out of the north and gusting 20-30 kts. These will also gradually dissipate as the low moves out this evening. Winds will become lighter overnight. Some patchy fog may form if winds fall to light and variable, but confidence in both fog and low winds is low. Still, low laying areas and water ways may still see patchy fog by Saturday morning that should burn off shortly after sunrise.

FSD WATCHES/WARNINGS/ADVISORIES

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