textproduct: Sioux Falls

KEY MESSAGES

- Scattered showers and areas of drizzle remain possible tonight through tomorrow. Rain won't be as widespread Friday as what we saw today, but be prepared for occasional pockets of light rain.

- The active weather pattern continues bringing a high chance (>70%) of additional rain late Friday into Saturday and again later Monday into Tuesday (>50%).

- Daytime temperatures remain below normal, but should climb closer to normal Saturday into Monday.

DISCUSSION

Issued at 242 PM CDT Thu Sep 24 2026

An area of steady light to locally moderate rainfall extends from around a Slayton to Yankton line and points east. This area of rain will gradually push east through the remainder of the afternoon and start to fall apart this evening over northwest Iowa. However, patchy drizzle will be possible after this rain departs especially along and east of I-29. A bit drier in the low-levels over parts of northwest Iowa tonight, so it may take a bit longer for drizzle to develop there. Farther west, especially into south-central South Dakota, we will see some breaks in the clouds which will allow temperatures to warm into the middle 70s. Some instability (around 500-750 J/kg) will be present along and ahead of a weak front over south-central South Dakota where this heating is occurring, but plenty of dry mid-level air should prevent scattered showers and storms from developing in these locations. In the off chance (<10%) we get a storm, severe weather is not expected as weak effective shear looks to be place.

Heading into tonight, a few showers will continue to be possible mainly along the Highway 20 corridor. Low stratus looks to spread back west through the night, but before it spreads back into south- central South Dakota, patchy fog can't be ruled out there. Drizzle will begin to become more likely heading into early tomorrow morning as cloud ceilings continue to fall, so keep the rain gear handy for your Friday morning commute. Scattered light showers will develop throughout the day, with chances gradually lifting northward through the afternoon due to strengthening warm air advection at 850 mb. These will be more of the hit or miss variety unlike what we saw today, so keep that umbrella nearby but rain totals will only be a few hundredths to a tenth of an inch during the day on Friday, except for locally higher amounts along the Highway 20 corridor Friday morning. Lowered the high temperatures a bit from the NBM for Friday given the cloud cover and drizzle, with highs mostly in the lower 60s. If some peaks of sun can be realized, a few middle to upper 60s for highs will be possible.

Rain chances will increase Friday night into Saturday morning as the main upper wave pivots through the area. The highest rainfall totals during this time frame will generally be over northwest Iowa and adjacent areas of southeast South Dakota and far northeast Nebraska, where around a half an inch to an inch of rain can be expected. A few pockets of 1-1.5" of rain (15-25% chance) can't be ruled out mainly along and southeast of a Spencer to Sioux City line. This rain should be spread out long enough where flash flooding concerns will be low where these highest amounts occur, but still be prepared for wet roads if traveling especially early Saturday morning.

Showers and very isolated storms will gradually push east through the afternoon, though once again some patchy drizzle will remain possible after any of the rain showers end at least through the early evening Saturday. Drizzle details will be refined as we get closer to the Saturday afternoon. Though some very patchy drizzle will be possible into Sunday morning, should mostly see dry weather for the day. This should allow for some of the warmest temperatures that we've see over the past few days, with highs in the upper 60s to middle 70s. Ultimately, these temperatures will be dependent on how quickly we can scatter out any morning clouds, so expect changes to the forecasted temperatures as we approach Sunday.

Rain chances do look to return once again on Monday, but especially Monday night into Tuesday. This will be as the West Coast longwave trough finally swings into the area. Will have to watch for any heavy rain once again with this activity, especially on top of the rainfall we've seen the past week. LREF probabilities show around a 30-40% chance of at least an inch of rainfall Monday night through Tuesday night, focused over northwestern Iowa. Trends will continue to be monitored as we get closer to next week.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 603 PM CDT Thu Sep 24 2026

Widespread stratus will begin to spread back westward after sunset, with gradual lowering back to IFR and even LIFR levels at times into Friday morning. Just enough lift in the lowest levels to lead to occasional periods of drizzle or sprinkles deep into Friday morning. Visibilities may fall below 4 miles at times, though I wouldn't be surprised to see visibility fall below 2 miles in higher elevation areas.

Minimal improvement is expected Friday, with occasional drizzle or showers. Ceilings may gradually mix up to MVFR levels in the afternoon once again. Winds remain south to southeasterly.

FSD WATCHES/WARNINGS/ADVISORIES

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