textproduct: Sioux Falls

KEY MESSAGES

- Sprinkles are possible this afternoon across southwestern Minnesota and adjacent portions of South Dakota and Iowa.

- Frost and freeze conditions are expected tonight into early Wednesday morning across the area - take precautions to protect sensitive vegetation. Frost/Freeze headlines go into effect late tonight.

- Cooler conditions continue this week. Dry weather expected mid week. Another round of showers and isolated thunderstorms is expected from Thursday afternoon through Friday. Severe weather is unlikely. Ensemble output suggest about a 10 to 30 percent chance for a half an inch of rain during this time.

DISCUSSION

Issued at 1245 PM CDT Tue May 19 2026

Cool high pressure settles into the area tonight and will bring a very good chance for temperatures tall to or below 35 for most of the area with temperatures at or below freezing possible north of I- 90. Thus a freeze warning is in place for highway 14 and nearby locations in SD with a frost advisory for the remainder of the area.

Isolated pockets of fog will be possible early Wednesday morning but at this time it does not appear as though it will become more widespread.

A weak wave will move through the area on Wednesday which could bring a few sprinkles but overall should mainly be an increase in mid level clouds. Otherwise slightly more mild temperatures are expected as southerly flow develops and brings highs back into the 60s for most locations.

Another weak wave moves across NE on Thursday and could bring some light showers to the Missouri River corridor into northwest IA. Precipitation amounts will be light as moisture with the system is very limited.

A bit stronger and more negatively tilted system will swing through on Friday bringing the next best chance for rainfall. Instability very minor with CAPE values generally 500 J/kg or less. The model soundings do indicate the potential for some efficient rainfall however so maybe some half inch or so amounts will be possible. The latest ensemble output indicating about a 10 to 30 percent chance for more than a half an inch and the latest Nam is indicating a couple of areas with more than a half an inch. Long story short, only minor impacts expected with no severe weather.

As this system moves northeast and out of the area a few lingering showers will be possible on Saturday, but warmer temperatures will begin to work into the region. Sunday through the middle of next week will see troughiness to the west and ridging to the east, leaving the area in warmer southerly flow. While there is very little agreement, there should be a couple of weaker waves that could bring showers and thunderstorms to the area, but for now confidence is too low to include in the forecast. Otherwise highs should be in the 80s with lows mainly in the 50s Monday through Wednesday.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1245 PM CDT Tue May 19 2026

Lingering MVFR ceilings are likely east of I-29 through about mid afternoon, with the entire area VFR after this. Some patchy fog will be possible late tonight into Wednesday morning, but confidence too low to include in TAF. Otherwise gusts of 25 to 30 mph likely through the afternoon but quickly diminish this evening.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Frost Advisory from 1 AM to 8 AM CDT Wednesday for SDZ050- 054>071. Freeze Warning from 1 AM to 8 AM CDT Wednesday for SDZ038>040- 052-053. MN...Frost Advisory from 1 AM to 8 AM CDT Wednesday for MNZ071-072- 080-081-089-090-097-098. IA...Frost Advisory from 1 AM to 8 AM CDT Wednesday for IAZ001>003- 012>014-020>022-031-032. NE...Frost Advisory from 1 AM to 8 AM CDT Wednesday for NEZ013-014.