textproduct: Sioux Falls

KEY MESSAGES

- Locally elevated fire danger concerns continue through the early evening hours today. With similar conditions in place for tomorrow, Sunday will also see a continuation in locally elevated fire danger.

- Frost is expected to develop tonight, mainly along and just south of the highway-14 corridor. Have issued a Frost Advisory for this area from 3 am to 9 am.

- Temperatures begin to warm through the upcoming work week, and by the end of the week may further warm to the 80s to potentially low 90s.

- A few chances for rain are expected. The first chance comes Monday night with the second one coming on Thursday and Friday. Both chances have a 15-30% chance of occurrence, highest Monday night. Severe weather risks remain low at this time.

DISCUSSION

Issued at 137 PM CDT Sat May 9 2026

Isolated sprinkles to light showers persist along parts of the Missouri River this afternoon. The rest of the area has cleared out, resulting in sunny skies and greater mixing. With highs topping out in the 60s to low 70s , humidity will fall to near critical to critical levels. Winds will remain breezy with gusts up to 20-30 mph. Thus, elevated fire danger is expected to persist for the rest of the afternoon hours. Winds will go light and variable overnight as the boundary layer stabilizes and surface ridging nudges into the Northern Plains. Low temperatures look to fall to the 30s to up to about 40F overnight. With locations generally along highway-14 falling below 36F, have decided to issue a Frost Advisory for locations along and just south of highway-14. The Advisory is in effect from 3 am to 9 am.

Sunday looks to be a rise and repeat of Saturday with high temperatures warming to the 60s and 70s. Dew points will be a little lower than today, so humidity values look to reach critical levels across a large swath of the forecast area. At the same time, soundings do show deeper mixing during the afternoon hours on Sunday. This will allow slightly stronger gusts to be mixed to the surface. Still, these gusts will only be to about 20-25 mph with an isolated few gusts up to 30 mph. Despite winds and humidity levels reaching critical levels, fuels continue to green which keeps fire danger capped at moderate. Thus, only elevated fire danger is expected across the area. Another cool night is expected with lows again falling to the 30s and 40s. This looks to result in another round of frost across similar parts of the highway-14 corridor.

The first half of next week continues to look warm and mostly dry. A shortwave trough will round the top of a ridge on Monday. Warm air advection (WAA) will strengthen ahead of this shortwave during the daylight hours. This will push high temperatures to the 70s and 80s across the area. Breezy southerly winds will accompany the warm temperatures with gusts up to 20-30 mph. Humidity values will fall to near critical to critical levels, leading to elevated fire danger again. A cold front tied to this wave will push through the area during the overnight hours. This front looks to result in just enough cooling to result in light showers along the boundary. Locations mainly in southwest Minnesota have the highest chances (20- 30%) for seeing light showers.

The upper level shortwave will deepen over the eastern US, putting the central Plains under upper level ridging. This will keep Tuesday and Wednesday dry. Humidity values look to again fall to near critical to critical levels. Winds look to be strongest behind the departing cold front on Tuesday which will result in high fire danger across the entire area. With high pressure in control on Wednesday, much lighter winds are expected on Wednesday which should keep any fire danger at bay. High temperatures look to remain above average in the 70s to low 80s.

The end of the week remains somewhat uncertain. Medium range guidance is in agreement in another shortwave trough pushing into the Western US but the evolution of this wave is highly uncertain. Latest 12z guidance has slowed the progression of this wave with some of the machine learning guidance showing this low cutting off from the mean flow entirely. As such, have reduced PoPs a bit on Thursday, now only up to about a 20% chance for rain. Have left similarly low PoPs for Friday but these chances for rain could increase if this wave was to take a northern trajectory. Saturday looks to remain dry but that can change depending on how the pattern evolves. If rain were to return to the area, there could be enough instability to promote thunderstorms, some of which could be on the stronger side. Aside from rain chances, the end of the week looks to be hot with highs warming to the 80s and even 90s.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 626 PM CDT Sat May 9 2026

VFR conditions expected through the period. Winds turn light and variable heading through the night, with winds then increasing heading into the daytime hours Sunday. Winds look to gust up to 15-20 kts out of the northwest by the late morning Sunday through the afternoon for most of the area.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Frost Advisory from 3 AM to 9 AM CDT Sunday for SDZ038>040- 053>056. MN...Frost Advisory from 3 AM to 9 AM CDT Sunday for MNZ071-072-080- 081-097. IA...None. NE...None.