textproduct: Sioux Falls

KEY MESSAGES

- Scattered showers with isolated thunderstorms be possible by late afternoon along and south of Highway-14. While severe weather is not expected, but an occasionally strong wind gusts up to 45 mph can't be ruled out.

- Additional showers and thunderstorms will be possible by Saturday morning along and south of U.S. Highway 18. While severe weather is not expected, small hail and wind gusts up to 45 mph will be possible with any stronger activity.

- After warmer conditions today, more seasonable conditions are expected over the weekend into early next week with highs mainly in the 70s to lower 80s.

UPDATE

Issued at 354 AM CDT Fri Jun 12 2026

A warmer and breezy day ahead! No significant changes forecast-wise. With the return of increasing westerly to southwesterly surface winds, expect temperatures to rebound with highs peaking in the low to upper 80s for the day. Otherwise, our focus will shift to our next rain chances (30%-40%) this afternoon as a weak wave intersects an approaching cold front leading to scattered showers with isolated thunderstorms. While severe weather is not expected, pockets of moderate rainfall along with occasional strokes of lightning will be possible with this developing activity with the focus being across areas along and south of Highway-14. Nonetheless, should see most of this activity progress out of the area by late evening. While there is potential for additional redevelopment across northwestern IA as the nocturnal LLJ strengthens overnight into Saturday morning; confidence is low on the coverage and evolution at this point given the weaker forcing. Nonetheless, if things can manage to get going; small hail and damaging winds up to 45 mph would be the primary hazards with any stronger activity. Lastly, most of this activity should push east of our area by midday on Saturday.

DISCUSSION

Issued at 242 PM CDT Thu Jun 11 2026

Light rain showers continue to taper off and move east out of the region this afternoon. A second round of showers and thunderstorms is possible this afternoon as the axis of the upper wave swings through the region. Instability is low and so severe weather is not anticipated. However, an area of enhanced stretching potential and vorticity advection will follow the trough axis. As updrafts for showers are forming a few brief, weak funnels may also form. Area most likely to see showers and possibly funnels is north of I-90 with the better probability along and north of Highway 14. Showers exit east by the early evening hours. Cooler and breezy northwest winds flow in behind the trough, limiting our highs today. Widespread gusts of 25-30 mph are expected with south central South Dakota possibly seeing gusts to 35 mph. Similar to the previous discussion, the NBM is continuing to come in a bit too warm. There is some difference in guidance on how far south the cooler air will penetrate. In general, along and north of I-90 will be in the low 70s decreasing to the upper 60s as you move north. Temperatures warm into the mid 70s as you move south. Overnight lows will be in the 50s.

Friday will see the upper pattern become more zonal as high pressure builds in at the surface. For most of the region dry conditions are expected with mostly clear skies. Highs will climb into the 80s with a few 90s sprinkled along the Missouri River Valley. Friday afternoon a weak mid-level disturbance approaches from the northwest. At the same time a surface inverted trough will approach out of the southwest. West winds at the surface will increase and become southwesterly as the trough passes through. Gusts of 20-30 mph will continue into Friday evening. WAA will push north on the nose of the inverted trough, enhancing ascent in an area of low- level convergence along Highway 14 in eastern South Dakota and western Minnesota. Isolated to scattered showers and thunderstorms may form as a result. Convective parameters are borderline to low with only about a 10% probability of severe weather development. However, deep layer shear is strong in the 50-60 kt range. This may result in isolated organized updraft or two capable of producing small to marginally severe hail. Deep, inverted V soundings indicate strong wind gusts of 50+ mph are the most likely threat. Storms exit to the east late Friday evening.

A mid-level short wave dives southeast into the region early Saturday morning, dragging an associated surface low and cold front with it. To the southwest, a second surface low pressure and warm front will begin to move northeast. Between the two an area of convergence will form south of Highway 18 and along and north of I- 80. In this area instability and mid-level lapse rates will increase over an area of 45-55 kts of deep layer shear. As the cold front progresses southeast Saturday morning another round of showers and thunderstorms is possible, mostly south of Highway 18. Similar to Friday night's storms, the convective set up is on the borderline to low side for severe weather (10% probability). Stronger storms that develop could produce small hail and strong wind gusts of 45 mph. Showers move east through the late morning and should be clear of the region by early afternoon. Winds behind the front will become northwesterly and breezy with gusts of 25-35 mph. The strongest gusts are expected over central South Dakota where a few gusts to 40 mph are possible. High temperatures will be cooler thanks to CAA behind the front, in the 70s to possibly low 80s for the southern Missouri River area.

Sunday a couple reinforcing pushes of CAA comes behind a series of dry short waves. Highs will be in the 70s. Winds will remain out of the northwest and diurnally breezy. Afternoon gusts between 20-25 mph are expected. Monday a stronger upper wave will begin to influence the region. Current guidance is in low agreement on progression of both the wave and attendant convective parameters. As of now, isolated to scattered showers and thunderstorms are possible from the late afternoon Monday into the overnight hours. Severe weather risks appear low, but the trends with this system will need to be monitored. Showers may linger into Tuesday afternoon. Wednesday through the end of the week looks to be dry.

Highs Sunday through Tuesday will be on the cooler side of climatology, in the 70s to low 80s. In addition, dew points will be low, generally less than 50 F and as low as the mid 30s F. Cooler highs and low dewpoints will make for good conditions to be working and playing outside. Wednesday through the end of the week highs climb back into the 80s and 90s with the return of higher humidity values.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 630 AM CDT Fri Jun 12 2026

Mainly VFR conditions with occasional MVFR vsbys will be possible this TAF period mainly due to developing showers and thunderstorms. Taking a look at satellite imagery, mostly clear conditions continue this morning and should persist through at least the first half of the day. From there, shower and thunderstorm chances will increase heading into the late afternoon to evening hours. However, KSUX was the only TAF site that we had confidence in. Otherwise, increasing westerly surface winds will become more northwesterly behind an approaching front overnight to end the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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