textproduct: Sioux Falls

KEY MESSAGES

- While confidence is low that additional storms will develop this afternoon, if storms develop, large hail up to ping pong balls and damaging winds to 65 mph would be the main hazards. A Level 1 of 5 risk for severe storms covers most of the area for this threat. Continue to monitor the latest forecast for the most up to date information.

- Similar to today, a conditional Level 1 of 5 risk for severe storms covers the forecast area Monday afternoon. The chance of development looks lower than today, but if a storm can form, large hail and isolated damaging winds could occur.

- 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 700 AM CDT Sun May 31 2026

Much of the morning activity has weakened though we do still have small areas of thunderstorms within broader scattered showers lifting north across the forecast area this morning. Severe weather is not expected with this activity, but storms may produce brief heavy downpours and of course lightning.

While confidence in exact timing/location of potential storm development this afternoon remains low, CAMs do continue to hint at isolated to scattered development within an unstable airmass. Shear is on the weaker side, but cannot rule out an isolated strong to severe storm with some support from a mid-upper level trough swinging northeast across the region. Given the steep lapse rates, large hail to ping pong ball size could occur.

An even more conditional threat exists for Monday afternoon, but with rising mid-upper level heights, think potential for storm development is even lower than today.

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 /12Z TAFS THROUGH 12Z MONDAY/

Issued at 700 AM CDT Sun May 31 2026

Scattered showers and isolated thunderstorms will lift north across the area this morning. Heavier showers may result in a period of MVFR-IFR visibility, but thunder will be limited in coverage, possibly impacting KHON early in the period. Areas of MVFR-IFR ceilings scattered throughout the area should improve to VFR by midday.

Late afternoon/evening could bring a threat of additional storm development. While exact timing is uncertain, attempted to target most likely window for thunder chances at KFSD/KSUX during the evening. Storm chances decrease after 01/06Z.

FSD WATCHES/WARNINGS/ADVISORIES

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