textproduct: Sioux Falls

KEY MESSAGES

- An isolated strong to severe storm is possible through 4 am. The main threats will be small hail and wind gusts to 50 mph, but a storm containing a wind gust up to 60 mph can't entirely be ruled out.

- The second chance for severe storms is Sunday afternoon and evening. However, confidence is low in development. If storms can develop, large hail up to ping pong balls and damaging winds to 65 mph would be the main hazards. Continue to monitor the latest forecast for the most up to date information.

- Moderate chances (30-60%) for rain will persist through the bulk of next week. However, severe storm chances continue to look low (near 5% or less) through next week. The better chances for rainfall appear to be Wednesday and Wednesday night.

UPDATE

Issued at 920 PM CDT Sat May 30 2026

An area of light showers over southwest Minnesota continues to lift out of the area this evening, with dry conditions elsewhere. A few showers look to develop near and south of the Missouri River Valley this evening as the low level jet ticks up slightly and where the greatest instability is located right now, around 1,500 J/kg. Despite weak CIN in this area, a lack of appreciable upper level support will limit any potential for thunderstorms through about 11 pm here locally. That changes as an upper wave continues ejecting across the northern High Plains and sends some vorticity our way.

A broken line of strong to severe storms stretching from western Nebraska into eastern Kansas is lifting north/northeast and will begin to move into the Missouri River Valley area in south-central South Dakota around 11 pm and continue to lift and spread east-northeastward through the night. Less instability and weaker shear in our area means the storms will generally be on the weakening trend as they move through, but there will still be around 500-1500 J/kg of CAPE to work with, highest along the Missouri River Valley near and west of the James River. This will be supportive of max wind gusts up to 50 mph and small hail in this area, though an isolated gust up to 65 mph can't be ruled out along with the strongest updraft being able to squeeze out some quarter sized hail. By 3-4 am as the activity pushes east of the James River, severe weather will no longer be expected. However, a disorganized line of showers and non-severe thunderstorms will continue into southwest Minnesota by daybreak.

DISCUSSION

Issued at 1256 PM CDT Sat May 30 2026

The latest runs of the models are more consistent on bringing a wave northward tonight with a broken line of convection. With very weak shear and CAPE values likely limited to 1000 J/kg or less, severe weather is very unlikely. An isolated storm could produce wind gusts to 60 mph or hail to the size of quarters, with the better chances near the Missouri River, possibly as far north as the James River. A few locations could pick up a little heavy rain, but for now storm motion looks quick enough that this heavy rain will likely last an hour or less at any one location. The better chances for this will be late evening into the overnight hours, generally from about 11 pm to 4 am for the stronger storms.

This wave should lift north of the area by late Sunday morning to early afternoon. Some showery activity will be possible through the morning, possibly lingering into the afternoon in southwest MN.

The next chance for showers and thunderstorms will be late Sunday afternoon into Sunday evening. This is a much lower confidence potential as the area could be muddled by cloud cover and even when the cloud cover clears, the latest models are hinting at a decent capping inversion. For now with only weak mid and upper level support, this cap may hold. There could be a slightly better wave move through Nebraska during this time which would bring a bit better chance closer to the Missouri River into parts of northwest IA. Also of note will be some low to mid level warm air advection moving across the area Sunday late afternoon into the night, starting in central SD late afternoon, which might be enough to spark some isolated activity and aid in breaking the cap. All-in-all a very low confidence set up during this time. In fact SPC just downgraded the area from a Slight Risk to Marginal.

Upper level ridging will be in place on Monday and Tuesday and limit any precipitation chances. Upper level troughing does spread into North Dakota Tuesday night through Thursday and could bring some showers and thunderstorms. The best chances should be Wednesday and Wednesday night. Faster westerly flow remains in place through the end of next week and this will likely support periodic chances for showers and storms as well.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 106 AM CDT Sun May 31 2026

A broken line of showers and storms extends across central and south-central South Dakota to start the period, and then more widely scattered showers and isolated storms are located near and east of I- 29. All of this activity is gradually lifting north-northeast this morning. The threat for severe weather remains low, but can't rule out the strongest storms having gusts up to 35 kts and small hail through the rest of the nighttime hours. After this initial round of showers and storms pushes out of the area after sunrise, we'll get a break from any storms through the early to mid afternoon, though MVFR stratus will linger behind this initial round of rain before lifting back to VFR across most of the area by the afternoon.

A second round of storms may develop late this afternoon into the early evening, but is expected to remain isolated. Still, enough confidence to at least include PROB30 groups for all sites with a mention of -TSRA. Winds through the period will be mainly out of the southeast with marginally breezy conditions through the day today. Winds will begin to turn lighter through Sunday evening.

FSD WATCHES/WARNINGS/ADVISORIES

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