textproduct: Sioux Falls

KEY MESSAGES

- Warm and predominantly dry conditions continue through most of the work week. Low (less than 25%) for showers late week near the US Highway 20 corridor.

- Warm and dry conditions and occasionally gusty afternoon winds could bring some fire weather concerns as grasses dry out.

- Widespread rain chances look to return late next weekend and early next week, but confidence in details remains low (less than 30%).

UPDATE

Issued at 914 PM CDT Mon Oct 5 2026

Still a few locations seeing south winds gusting 20-25 mph early this evening, but gusts are lower and less widespread than we saw prior to sunset. These sporadic gusts may continue into the late evening, but for most locations, gustiness should diminish as temperatures continue to cool and the surface-based inversion strengthens. The exception will be along and downstream of our higher elevation areas in south-central South Dakota and southwest Minnesota where a low level jet may help maintain occasional gusts in the 20-30 mph range.

Overall, previous forecast is on track and will continue to adjust for recent NBM cool/moist bias by blending warmer/drier guidance into daytime temperatures/dew points, respectively. The moist bias also seems to have some impact on nighttime lows, especially on the clear sky/light wind nights of late. As such, will nudge low temperatures toward the cooler side of guidance for at least the next couple of nights.

DISCUSSION

Issued at 235 PM CDT Mon Oct 5 2026

REST OF TODAY/TONIGHT: Shaping up to be another gorgeous early October day with temperatures in the 70s and lower 80s. Surface high pressure slides east today, with tightening SPG ahead of developing trough across the western Dakotas and southern Canada, were seeing gusts 25-35 mph. Some gusts around 40 mph possible in south central SD. Southerly flow and WAA continues to keep conditions warmer and drier, so raised highs and lowered dew points again for today as NBM remains too cool/moist. Warmer temperatures, dry conditions, and stronger winds could lead to some very locally elevated fire concerns this afternoon and early evening for anywhere fuels have begun to dry.

Weak mid level wave moves through this evening into tonight. Breezy conditions continue into the overnight hours, although some gusts around 30 mph remain possible near/along the Buffalo Ridge with the LLJ increasing. May see some lower clouds develop overnight ahead of a boundary but no precipitation is expected. Lows tonight remain mild, only falling into the lower and mid 50s.

TUESDAY-WEDNESDAY: Northwesterly flow aloft promotes a couple of weak waves through the northern and central Plains; however, lack of moisture keeps dry conditions in place. Surface boundary continues to slide east during the day Tuesday into the evening, with high pressure moving in for Wednesday.

Continued the trend of raising highs and lowering lows and dew points from the NBM given the continued cool and wet bias. CONSShort in addition to the 90th (higher) and 10th (lower) NBM percentiles were incorporated in to make those changes. Highs near and above 80 for most of the area Tuesday, which is about 10-15 degrees above seasonal averages. Slightly cooler Wednesday thanks to more northwesterly surface flow and CAA. Highs in the 70s and lows in the upper 40s and lower 50s.

THURSDAY-FRIDAY: Surface high slides east Thursday, with continued northwesterly flow aloft. By Thursday night, most guidance shows a surface warm front move north. Guidance is split on the track and strength of any lower and mid level waves through Friday, so confidence is lower during this time. In addition to timing and track differences, next biggest question is the depth of any moisture return. GFS/GEFS remain more bullish on the potential for measurable precipitation, with moderate to high chances (over 40%), with the ECMWF ensemble lower (40% or less). GEFS also has the highest (30% or less) probability of a tenth of an inch of rain with other ensembles even lower. Temperatures generally near to above normal.

THE WEEKEND/EARLY NEXT WEEK: Although guidance varies on the details, all deterministic models point to a shift in the pattern through next weekend and into early next week. A quick short wave moves through early in the weekend. By Sunday, ridging aloft shifts east with troughing digging into the western CONUS, bringing southwesterly flow to the region. Low pressure strengthens and moves east into the early part of the week bringing more widespread precipitation chances. Ensemble probabilities from the GFS and ECMWF show moderate to high (over 50%) chances for at least a tenth of an inch of precipitation into early Tuesday.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1100 PM CDT Mon Oct 5 2026

A southwesterly low level jet will maintain moderate gusts in our higher elevations, namely southwest Minnesota and south-central South Dakota, through the nighttime hours.

This low level jet will also result in a period of low level wind shear at TAF locations as it shifts east across the region overnight. The low level wind jet and associated wind shear will decrease by 13Z-14Z. Lighter southerly winds at daybreak will gradually turn to the west and northwest on Tuesday as a weak boundary moves east.

VFR conditions will prevail through the period.

FSD WATCHES/WARNINGS/ADVISORIES

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