textproduct: Sioux Falls

KEY MESSAGES

- An extended period of warm and dry conditions is expected for much of the upcoming work week.

- Warm temperatures and occasionally gusty afternoon winds could begin leading to fire weather concerns as fine fuels begin to dry out.

UPDATE

Issued at 316 AM CDT Sun Oct 4 2026

Taking a look across the area, mostly clear skies continue with a few higher clouds moving in this morning. After a cooler start, a beautiful day is ahead as highs approaching the upper 60s to low 70s with lighter surface winds. From here, the forecast remains on track with conditions expected to remain dry with a surface high overhead. Looking ahead, most of the week should continue to be dry as detailed in the discussion below. However, we're starting to see some low potential for rain by the second half of Thursday with the focus being along the Missouri River Valley. Its worth noting that this sentiment is also reflected in the ensemble guidance with both the EURO and GEPS showing only 10-20 percent probabilities for 0.10" of an inch of QPF. Otherwise, daily highs will likely remain in the upper 60s to mid 70s for most days with the potentially for a few low 80s on Tuesday west of I-29.

DISCUSSION

Issued at 217 PM CDT Sat Oct 3 2026

REST OF TODAY/TONIGHT: Sprinkles/showers continue to move east this afternoon, mainly along and north of I-90. First round of showers with the initial WAA and the LLJ continues to push east of I-29 this afternoon. There's been enough MUCAPE (generally 500 J/kg or less) for some lightning near and north of US Hwy 14, but this risk has quickly diminished with the loss of the instability. No lightning has been observed in our area for the last hour or so, and think risk is now < 10% for the rest of the afternoon. Next area of showers across central and northeastern SD is tied to the mid level wave and moves through during the afternoon and early evening hours, again staying mainly north of I-90. With dry sub cloud layer and high cloud bases, any rainfall accumulation remains minimal today.

Strongest winds have diminished, so allowed the Wind Advisory to expire at 1 PM CDT. Expect southerly gusts ahead of the front 30-40 mph this afternoon. Have also observed some 30-40 mph gusts from the northwest just behind the front, which will continue into the evening hours. Front has been moving through a little more quickly than previously expected. Despite showers and breezy conditions, it's a pleasant early October day with temps in the 60s and 70s.

Surface high pressure begins to slide in from the northwest late tonight. With winds tapering down overnight and clearing skies, would not be entirely surprised to see some patchy river valley fog by daybreak Sunday. HREF probability of visibility below 5 miles is low (less than 30%) and very isolated, so kept mention out of the forecast for now. We'll fall into the mid 40s and lower 50s.

SUNDAY: Surface high pressure remains overhead to end the weekend, with neutral to CAA and light northwesterly winds most of the day. This should keep temperatures a bit cooler for most of the area, with highs in the mid and upper 60s. Lows fall into the mid and upper 40s again as surface high moves east.

THE UPCOMING WEEK: Mid/upper level high pressure remains in place through the work week across the southwestern US. This keeps the central and northern Plains in northwesterly flow, allowing a few short waves to track across the region. Highs in the 60s and 70s with lows generally in the 40s and 50s.

Monday night into Tuesday sees a couple of these subtle and weak waves through, as well as a cold front Tuesday. Soundings for this period are very dry, so precipitation is not expected. Main impact will be breezier winds Monday afternoon and night with gusts 30-40 mph as the SPG tightens ahead of the front. Tuesday looks to be the warmest day of the upcoming week, although how warm depends on how quickly the front tracks through.

Guidance is quite varied handling the next surface low Thursday and any associated rain chances. Deterministic GFS is currently the strongest with this feature and would bring more widespread precipitation chances; however, confidence is low given model spread and ensemble probability of more than a tenth of an inch less than 20%, so have left the very low NBM pops as is. Troughing begins to dig into the western US by next weekend bringing the return of southwesterly flow and possibly more precipitation chances.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 546 AM CDT Sun Oct 4 2026

VFR conditions will continue this TAF period. Besides some high-level clouds, light surface winds will continue through at least 06z Monday. However, southeasterly winds will gradually increase into Monday morning.

FSD WATCHES/WARNINGS/ADVISORIES

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