textproduct: Sioux Falls

KEY MESSAGES

- Warm and predominantly dry conditions continue through most of the work week. Low (15-25%) chance for showers Thursday night into early Friday morning, mainly south of US Highway 18.

- Warm and dry conditions and occasionally gusty afternoon winds could bring some fire weather concerns as grasses dry out, with Saturday being the focus for stronger wind gusts.

- Better rain chances (20-40%) and cooler temperatures look to return early next week, but confidence in details remains low.

DISCUSSION

Issued at 228 PM CDT Tue Oct 6 2026

Warm and sunny weather will continue through the rest of this afternoon and early evening, making for a great time for outdoor activities! Quiet weather continues tonight with lows dropping to the upper 40s to lower 50s. Can't rule out some patchy fog mainly in river valleys and other low-lying areas early Wednesday morning, but chances of development are low (around 20%) at time. Northwesterly flow aloft will be in place heading into the day on Wednesday, and this will send some high clouds into the area. This will act to lower high temperatures than compared to today on Wednesday, but still above average in the lower to middle 70s. If clouds are a bit thicker and move in faster than expected, then high temperatures may be a bit cooler ranging from the upper 60s to lower 70s. On the flip side, a slower arrival and/or thinner clouds could result in slightly warmer temperatures than currently forecast. Winds look to increase slightly tomorrow, gusting to 25 mph along the Highway 14 corridor. Could have a few gusts pushing towards 30 mph in those locations during the afternoon hours. High pressure looks to settle into the region Wednesday night and will settle down the winds to very light to calm. Cloud cover associated with the northwesterly flow will likely prevent maximum cooling from being realized, but should still be a bit cooler (though still above average) night than compared to tonight. Lows by sunrise Thursday will be in the middle to upper 40s.

High pressure slides eastward on Thursday, allowing for the return of southeasterly flow to the area. The low levels still look to be pretty dry during the day, but the southerly flow will eventually bring in enough moisture by Thursday night to allow for some showers to develop. The best chances (15-25%) will be south of Highway-18. Amounts are expected to remain light, only a couple hundredths since much if not all of the saturation will be occurring below the DGZ. Only way I can see an area picking up to a tenth or two will be if any of the showers can tap into some elevated instability and become a weak thunderstorm. Chances for this are less than 15%. Any showers should push east of the area by the mid morning hours on Friday, leading to an overall sunny day. With the continued southerly flow in place, look for temperatures to warm well above average once again into the middle to upper 70s, with a few low 80s in south-central South Dakota.

Very warm weather will continue into the weekend, though a breakdown in this warm and dry pattern may start into early next week. First, Saturday looks to be a warm and breezy day with highs likely in the 80s for most areas. In terms of wind gusts, the 06.13Z NBM has a 30- 60% chance of wind gusts over 45 mph, while the 06.12Z European ensemble has a less than 10% of this occurring. So a fairly large spread in what the max wind gusts will be, but will also have to watch this day for potentially some fire weather concerns. However, do think we'll need to see some serious drying of fuels and browning of grasses before this becomes a threat. Trends will be monitored.

Meanwhile out west, a trough will be digging into the Pacific Northwest and become the main focus for rain chances into next week as it sends some upper waves our way. Deterministic guidance diverges significantly regarding when we see the best rain chances, and as such the NBM maintains broad 15-35% PoPs starting late Sunday night into the day on Tuesday. The LREF is a little bit higher (in the 20-40% range) during that time, which makes sense given that there will probably be a storm system sometime next week with the active pattern aloft, it's just a matter of when we'll see see it move through. In terms of amounts, the LREF shows the highest 24-hour rainfall totals between Monday morning and Tuesday morning, with a 15-25% chance of totals greater than a quarter of an inch. The return of rain chances and the clouds associated with it will result in temperatures much closer to average on Monday and especially by Tuesday, though exact temperatures will continue to be refined as the track and timing of the rain next week becomes more apparent.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 639 PM CDT Tue Oct 6 2026

VFR conditions will prevail through the period, with light northwest to variable winds at/below 12kt through Wednesday morning. Deeper mixing may draw stronger northwesterly wind gusts to the surface Wednesday afternoon, perhaps reaching 20-25kt in areas north of I-90, and 15-20kt along/south of I-90.

Exception to VFR conditions may be very localized visibility reductions if agricultural activity near an airfield produces near surface dust/haze into this evening. Also a low potential (20% or less) for shallow valley fog toward morning. However, confidence in either scenario impacting our TAF sites is too low to include.

FSD WATCHES/WARNINGS/ADVISORIES

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