textproduct: Sioux Falls

KEY MESSAGES

- Warmer today with highs in the upper 80s-lower 90s. Breezy southeast winds gusting 25-35 mph over central South Dakota and decreasing as you move east. - A system wraps north Sunday into Monday and will bring scattered showers and thunderstorms to the area. Severe weather chances are currently low.

- Temperatures heat up this weekend into next week. There is a moderate chance (30-50%) of highs exceeding 95F Tuesday and Wednesday, mainly in portions of southeast South Dakota. Be prepared to enact any heat related safety measures.

- While details in timing and coverage are still uncertain, Tuesday night-Wednesday could see severe risks return.

UPDATE

Issued at 430 AM CDT Sat Jun 6 2026

Have seen some patchy, mainly light fog (visibility 3-5 miles) early this morning, mostly near and north of Highway 14. Not seeing much signal of this on satellite this far south, likely indicative of the patchy and/or more shallow nature of the fog when compared to areas farther north in west-central Minnesota. As such, expect the fog to burn off rather quickly after sunrise with most areas clear of fog by 8 am.

Today and really most of this weekend should be on the quiet side. Scattered showers and storms could lift into areas east of I-29 Sunday, but lack of shear and meager mid-level lapse rates should limit severe potential. Latest Day 2 outlook from SPC did expand the Level 1 of 5/Marginal risk into our far western CWA. This is likely for a low chance that storms in the high plains maintain some strength as they move through central SD after midnight/early Monday morning. However at this time, the severe risk in our area looks low.

Tuesday-Wednesday come into focus for an increase in heat and humidity ahead of an approaching cool front. Latest models are trending a little faster with the front on Wednesday. While not sharply colder in the ensemble data yet, the probabilities for temperatures exceeding 95F in our western counties has dropped 10-20% from the previous model runs, keeping the probability around 30-50% for both Tuesday and Wednesday. That said, with humidity also expected to increase, we are seeing a couple of days with moderate to major Heat Risk with heat indices likely topping 100F in some locations. Plan now to ensure you have access to cooling locations.

While details in timing/location are still coming together, the proximity of the above-mentioned cold front and associated mid to upper level trough will bring severe weather risks back to the region by mid-week as these features move into the hot and humid air mass over our region. This is depicted by the latest Days 4-8 outlooks from SPC which place portions of our area in a 15% risk for Day 4/Tuesday (our SD counties Tuesday night) and Day 5/Wednesday (most of the CWA, east into Minnesota and northern Iowa). Monitor the forecast through the coming days for additional details.

DISCUSSION

Issued at 245 PM CDT Fri Jun 5 2026

Storms have developed over far western Minnesota and are moving east-southeast this afternoon. This activity is associated with an upper wave that will be moving across the northern Midwest into the Great Lakes region through tonight. With the better upper level support off to our northeast, the chance for thunderstorms is low and the chance for severe weather is even lower in our southwest Minnesota counties. If a storm were to sneak in (<20% chance), then it will have around 1,000 to 1,500 J/kg of MLCAPE and around 35-40 kts of shear to work with, which could support an isolated 60 mph wind gust or instance of half dollar hail. The main time frame for this highly conditional threat is through 9-10 pm.

Otherwise, tonight will feature mainly clear skies with calm winds, and thus patchy fog will be possible in spots. The NBM favors areas near and east of I-29 for fog while the REFS favors north of I-90. Would lean towards REFS on this one as there is plenty of moisture north of I-90 left behind from recent thunderstorms and these areas will cool the fastest towards the dew point tonight. Clouds may also linger longer near and south of Highway 20 as well tonight associated with storms to our south, so this could limit fog potential there. Speaking of those storms, they look to develop over eastern Nebraska and southwestern Iowa through the evening hours, but this is expected to remain south of the area through tonight. One thing worth watching with these storms is any potential outflow boundaries that are left behind that could affect weather for Saturday. Some CAMs including the 05.12Z HRRR and RRFS-2 show some storms developing over the Highway-20 corridor tomorrow afternoon and evening, perhaps associated with one of these potential boundaries lifting northward into our area, so that will be something to watch. But when looking at overall chances according to the REFS and HREF, the chance of rain is less than 20%. So otherwise, dry, sunny, and very warm weather is expected on Saturday, and with ridging aloft, look for highs in the upper 80s to lower 90s, hottest along the Missouri River Valley.

On Sunday, guidance shows and upper low moving north across the central Plains. To the west, a surface low will drag a cold front into western South Dakota. The EC Ensemble shows an up to 60% chance of measurable precipitation as early as Sunday morning over northwest Iowa associated with aforementioned upper low but most other guidance brings better rain chances into the afternoon. Cloud cover ahead of this system will mean poor destabilization ahead of any thunderstorms over northwest Iowa, so the severe weather threat potential looks low at this time. The cold front off to our west will help fire off strong to severe storms over the northern High Plains Sunday afternoon/evening, and some of these will try to push into areas west of I-29 into early Monday morning. However, waning instability and storms potentially outrunning the best shear will mean the chances for severe weather locally with this is also fairly low at this time.

The main story heading into the next work week will be the building heat, starting Tuesday. That's when highs look to climb into the 90s area-wide, with the potential for highs nearing 100 along the Missouri River Valley. Then Wednesday may be even hotter as a front turns winds more southwesterly in south- central South Dakota. The NBM has come down a little bit in temperatures, but looking at the LREF, it has a 30-50% chance of highs above 95 in south-central South Dakota and then a 40-70% chance on Wednesday in that area. One limiting factor to this heat being realized on Wednesday is that storms may form along and ahead of the front and so that could affect heating. Either way, keep up to date with the latest forecast and be prepared to take heat related safety measures!

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 633 AM CDT Sat Jun 6 2026

Lingering areas MVFR visibility in BR or MIFG along the Highway 14 corridor east of KHON will dissipate by 13-14Z. Thereafter, VFR conditions are expected to prevail through the period.

Southeast winds increase by midday, with occasional gusts 20-30kt along and west of the James River Valley through sunset.

FSD WATCHES/WARNINGS/ADVISORIES

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