textproduct: Sioux Falls

KEY MESSAGES

- Dry and seasonably mild conditions will dominate the week ahead with only very minor chances (<20%) for showers into early next week.

UPDATE

Issued at 858 PM CDT Thu Oct 1 2026

No major changes to the forecast tonight and tomorrow. Still see some mid level clouds mainly west of I-29 this evening with some returns showing up on radar. However, with plenty of dry air below the clouds, this activity will likely not reach the ground. East of the clouds, temperatures are dropping quickly with many locations already in the lower 50s. With high pressure settling into the region, expect a night with calm winds along with a bit of a chill in the air. Temperatures look to drop mainly into the 40s, though a few spots along the higher elevations of southwest Minnesota and adjacent areas of eastern South Dakota will drop into the upper-30s. Still looking at very low chances for frost to develop in these areas as hourly temperatures this evening have been running mostly as expected. Thus, will continue to hold off on issuing any headlines.

As the aforementioned high pressure system moves east of the area on Friday, southeasterly winds will return throughout the day. Winds will increase in western areas as the surface pressure gradient tightens ahead of a develop low pressure system over the northern High Plains. And so winds from about Chamberlain to Gregory could gust up to 30-35 mph at times in the afternoon, with winds decreasing as you head east. At the same time, a weak wave moving through the northern Plains into the upper Midwest will bring the mid level clouds north and east through the area. Soundings are starting to show a little bit of instability within this cloud layer, but dry air below will reduce anything that makes it to the ground to just a few sprinkles. Did raise the high temperatures by a degree or two for Friday in most areas since we over performed a bit today despite some cold air advection. And unlike today, we'll see the return of southeasterly flow and so the NBM could be running a bit too cool. Regardless, it should be a cool day especially in our northern areas which will have to deal with some of the mid level clouds, with highs ranging from the upper 50s there to the middle 60s in south- central South Dakota.

DISCUSSION

Issued at 117 PM CDT Thu Oct 1 2026

Cool, dry high pressure settles southward tonight leading to lighter winds and clearing skies. May be some mid/high level clouds so that could offset some of the potential radiational cooling. The NBM 10th percentile does sneak down to about 36 in parts of southwest MN and nearby locations, but for now expect low temperatures around 38 or higher with lower to mid 40s near and west of I-29. So, not a zero percent chance for patchy frost, but too low to issue any headlines.

High pressure slowly moves east on Friday, so expecting some cool high temperatures. Highs generally in the low to mid 60s. Southerly flow increasing in the afternoon west of I-29, then across the entire area Friday night. Lows may need to be increased a bit into the lower to mid 50s given the expected 925 mb temperatures.

Saturday will be warmer with southerly flow turning southwest during the afternoon. Highs more consistently in the upper 60s to lower 70s.

A cool front moves through Saturday night into Sunday bringing cool and dry conditions.

Monday will be dry and cool with highs in the 60s while southerly flow increases Tuesday into Wednesday ahead of the next wave, bringing a better potential for highs in the 70s.

A series of weak, moisture starved systems will move through the Northern Plains over the next 7 days, resulting in little to no impacts. The better chances for sprinkles or very light showers will be Friday and Saturday then again Monday into Tuesday. Both show waves moving by to the north with the tail end of forcing scraping by the area. Little to no instability with each wave coupled with abundant dry air leaves little in the way of precipitation production potential. Friday and Saturday looks like the better chance for a spotty shower will be north of I-90 where better mid level saturation is expected.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1112 PM CDT Thu Oct 1 2026

Mid level clouds will start to move to the east-northeast through the day on Friday, bringing a slight chance of sprinkles, but most likely virga to the Highway 14 corridor during the daytime hours Friday. Light northerly winds to start the period will turn southeasterly heading through the daytime hours Friday, with breezy conditions expected in south-central South Dakota by the late morning/early afternoon. This is when we'll see winds that could gust to around 30 kts.

FSD WATCHES/WARNINGS/ADVISORIES

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