textproduct: Sioux Falls

KEY MESSAGES

- A cold front remains on track to move through the area today and Monday, bringing cooler, near seasonable, temperatures into next week.

- Mainly dry conditions are expected on Monday and Tuesday before chances for rain increase by the middle of the week. While a 30-60% chance for rain is in the forecast, details regarding this chance for rain can still change.

UPDATE

Issued at 410 AM CDT Sun Oct 11 2026

Another very mild night with early morning temperatures near to above normal high temperatures for this time of year. Most of the forecast area remains on the warm side of a cool front which extends from north central Nebraska to the Red River Valley as of 4 AM. A few clouds are moving across western portions of the forecast area early this morning and we could see a greater increase in high clouds west of I-29 through the day. This along with the slowly advancing cool front will keep temperatures in our far west in the 70s today, but locations along/east of U.S. Highway 81 will again climb into the mid to upper 80s. Record highs are generally near to slightly above 90F, and with the NBM 90th percentile highs near 90 in a few areas for today, will again have to monitor for near-record highs.

Highs for Monday are a little lower confidence as timing of the front progression varies among the models, and locations behind the front could see more widespread/thicker cloud cover. For this reason, did not alter the latest NBM highs which range from upper 60s in our far west to upper 80s in parts of northwest Iowa. However, it's possible the temperature gradient could be even tighter than currently reflected in the broad ensemble mean.

DISCUSSION

Issued at 247 PM CDT Sat Oct 10 2026

Elevated fire danger continues this afternoon with southwesterly winds gusting to 25-40 mph while humidity levels have fallen to 25- 35%. More details about the fire danger can be found in the fire weather discussion below. Highs have warmed to the 80s with a few locations breaking into the low 90s. These warm temperatures have warmed to near record highs for today. Could see a few records broken before temperatures begin cooling this evening. Should see winds remain steady to slowly weakening for the rest of the afternoon hours before more noticeably weakening this evening after sunset. Humidity will be increasing during this period of time as well, putting an end to the fire danger threat for today. However, a tighter surface pressure gradient (SPG) will remain in place through the night. This will keep elevated southerly winds through the night, resulting in another mild night with lows only falling to the 60s. These temperatures will again be near record warm low territory.

Sunday will be a much nicer day as low level pressure gradients relax across the area. There will still be marginally breezy southerly winds with gusts up to 20-25 mph. High temperatures will remain warm in the low to mid 80s thanks to the the thermal ridge axis sitting overhead. A cold front will be beginning to push into the area from the west. Thankfully, this front will deliver noticeably colder temperatures with overnight lows falling down to the 50s and 60s.

The front looks to push through the forecast area on Monday, leading to slightly cooler temperatures, but still above average highs in the upper 60s, 70s, and 80s. The coolest temperatures will reside in the northwest part of the forecast area. A weak mid level wave will pass through the area behind the surface cold front. There may be just enough moisture to squeak out some light showers along and north of highway-14. The ensembles show a broad 50-90% chance for rainfall totals to exceed a hundredth of an inch. Their probabilities quickly diminish to near zero for amounts to exceed a tenth of an inch. Rainfall chances (15-30%) will be highest during the daylight hours.

Tuesday looks to be a dry day as upper level ridging slightly strengthens ahead of a deepening upper level low over the southwest CONUS. Withe the previously mentioned cold front through the forecast area, highs will be closer to seasonable in the 60s to low 70s.

Chances for rain begin to return to the area on Wednesday as the previously mentioned upper level low begins to eject into the Plains. However, medium range guidance continues to show a large variance in how this upper wave will evolve. Some show the wave continuing to push eastwards while others show a closed low developing and cutting off the mean flow. The ensembles also reflect these possibilities as well with the GFS ensembles having the wave continue to push into the Plains while the Euro and Canadian ensembles show a cut off low developing. Each of these models respective machine learning (ML) counterparts also show the same evolution. Looking to the clusters shows that the most favored cluster has the upper low closing off and detaching from the mean flow aloft. That said, the most favored cluster has this closed low just northeast of the four corners area and bringing increasing chances for rain to the forecast area. While this does look to be a more favorable solution, did not want to stray from the NBM's PoPs (30-60% chance) at this time as changes in the upper level patterns evolution remains possible. That said, the potential for rain and associated cloud cover looks to keep temperatures near seasonable in the 60s for Wednesday and Thursday. Friday looks to be the coolest day as broader troughing may encompass the Northern Plains. Should this play out, then highs may fall to near to below average in the 50s.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 640 AM CDT Sun Oct 11 2026

Early morning low level wind shear will continue to weaken as the low level jet shifts east and diurnal mixing commences by 14Z-15Z. Southerly winds will become gusty again in areas near and east of U.S. Highway 81, but to a much lesser degree than yesterday with gusts generally 20-25kt through sunset. Farther west, a weak cool front will turn winds to the northwest and north, with this front progressing toward I-29 through this TAF period.

VFR conditions will remain prevalent through 06Z, but thereafter MVFR ceilings may begin to build southward into far western and northern portions of the forecast area. These lower ceilings may impact KHON and other portions of the Highway 14 corridor late in this period, but should remain well north and west of KFSD and KSUX.

CLIMATE

Issued at 410 AM CDT Sun Oct 11 2026

Record High Temperatures:

October 11: KFSD: 90/2015 KSUX: 91/2015 KHON: 91/1910 KMHE: 95/1910

Record High Minimum Temperatures:

October 11: KFSD: 67/1997 KSUX: 66/1997 KHON: 68/1997 October 12: KFSD: 62/1995 KSUX: 65/2008 KHON: 61/1984

FSD WATCHES/WARNINGS/ADVISORIES

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