textproduct: Sioux Falls

KEY MESSAGES

- A few sprinkles may move through portions of the Missouri River Valley west of Yankton this morning. The main threat will be localized gusty winds to 20 to 30 mph with the showers.

- Additional shower and very isolated thunderstorm chances are possible Monday afternoon into Monday night. If a storm can develop, wind gusts to around 50 mph will be possible. The better chances will be south of Highway 18.

- After seasonal temperatures into Monday, cooler than normal temperatures return midweek. Areas of early morning frost or near-freezing temperatures are possible by early Wednesday and Thursday.

UPDATE

Issued at 350 AM CDT Sun May 3 2026

Evening shower activity has moved off to the east of our forecast area, but watching a narrow band of light showers or sprinkles in western South Dakota. Trajectory could bring this activity into portions of the Missouri River Valley this morning, though fairly dry sounding profiles below 7-10kft may preclude anything from reaching the surface. If we do see any sprinkles, brief wind gusts of 20-30 mph will be possible.

Otherwise, winds in general may be on the more gusty side across our eastern counties this morning aided by weak cold advection in the wake of cool front sliding southeast. Surface ridge sags into our area this afternoon, which should allow for generally lighter winds. However, decent mixing would support occasional gusts to around 20 mph.

As far as temperatures, modest overnight winds and mid-high level clouds have kept readings rather mild with 3 am temperatures still in the 50s most areas. Should still see readings dip into the mid to upper 40s by daybreak, but mild start will set the stage for an equally mild day. Despite recent rains and greening grasses, have seen temperatures overperform the NBM guidance in recent days. With aforementioned mixing expected, decided to nudge temps/dew points a little warmer/drier this afternoon. This yields relative humidity levels as low as 20 to 25 percent near and east of I-29, which could lead to localized elevated fire weather conditions in areas where the Spring green-up is lagging. Coordinated issuance of a Special Weather Statement in our MN counties where satellite greenness estimates indicate this may be more of a concern than locations farther to the west and south.

DISCUSSION

Issued at 130 PM CDT Sat May 2 2026

A fast moving wave will track southeast into ND and MN into tonight. This will spread some mid level moisture through the area that happens to reside within the dgz. With some very weak instability lifting from about 700 mb a few showers will be likely this evening. Severe weather is not expected but with a very dry sub cloud layer a few wind gusts to 35 to 45 mph will be possible. The better chances will be near and east of I-29.

A weak front will settle into the area late tonight but have little affect on temperatures Sunday. Winds will turn from the north to more westerly on Sunday evening. Highs mild in the mid 60s to lower 70s. Model soundings indicate maybe a little patchy cumulus in the afternoon but no instability for showers, so looking dry.

A weak wave and marginal instability, generally 500 J/kg CAPE or lower, will move into the area Monday. A broad trough to the north will settle south and push cooler air into the area. Near and ahead of this front, generally south of I-90, the environment may support some gusty winds to around 50 mph with the stronger showers or isolated thunderstorms that may develop later Monday afternoon and Monday evening.

Northwest flow aloft remains in place Tuesday through next weekend. This will bring a series of waves through the area but for now moisture looks fairly limited so the threat for more than scattered showers and isolated thunderstorms remains low. Currently the better chances appear to come with a weaker wave Wednesday into Wednesday night then Thursday night into Friday with a bit stronger wave.

Outside of the shower and thunderstorm potential will be frost and freeze potential with light winds on Wednesday morning and Thursday morning. Fairly widespread morning lows of 30 to 35 are expected.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1245 AM CDT Sun May 3 2026

VFR conditions expected through the period. Isolated light showers/sprinkles linger to start the period mainly southeast of a KMML to KFSD to KYKN line and are moving to the south and east. This activity has been able to still bring gusts to around 25-30 kts down to the surface when it passes through, and this will be a possibility at KSUX for the next couple of hours (30% chance). Otherwise, LLWS concerns continue for northwest Iowa and adjacent areas of South Dakota and Minnesota over the next few hours.

A cold front clears the area by sunrise, turning winds north- northwesterly area-wide this morning into the afternoon. Winds will then gradually turn back westerly and then southwesterly this evening. Winds gusts this afternoon top out around 20 kts.

FSD WATCHES/WARNINGS/ADVISORIES

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