textproduct: Sioux Falls

KEY MESSAGES

- Scattered showers along with a stray thunderstorm are possible Friday evening near and north of I-90. Severe weather is not expected, but wind gusts up to 55 mph can't be ruled out.

- Another round is possible early Saturday morning along and south of Highway 18. Severe weather is once again not anticipated, but small hail and wind gusts to 45-50 mph are possible.

- After a brief warm-up Friday, the weekend through early next week will see cooler highs in the 70s to lower 80s and lower relative humidity values.

UPDATE

Issued at 907 PM CDT Thu Jun 11 2026

Scattered light showers/sprinkles over northern South Dakota are moving into the Highway 14 corridor this evening along and ahead of an upper wave moving across the northern Plains. This activity should gradually decrease through tonight as the already limited elevated instability continues to wane. Otherwise, a quiet night is ahead with lows in the 50s and diminishing winds across the area. Despite the clearing skies and recent rainfall, fog is unlikely to develop given that winds will remain slightly elevated heading into tomorrow morning.

A warmer day is in store for Friday as more sunshine is expected, with highs back into the 80s across the area. Most of the day and most of the area will be dry, but scattered showers look to develop mainly north of I-90 late tomorrow afternoon into the early evening as a boundary moves across the area. Some elevated instability may lead to a couple of lightning strikes, but the main concern looks to be some gusty winds with these showers. This is supported by inverted-V soundings showing the potential for deep mixing which may help bring down some stronger wind gusts of up to 55 mph to the surface. The main factor that will limit this potential for strong winds is that showers may not really get going until closer to sunset, when the nocturnal low level inversion begins to take shape and this may help prevent some of these stronger winds from making it to the ground. Some uncertainty as to whether or not these showers develop west or east of the James River, but look for this activity to move from west to east through the evening, exiting into central Minnesota by 11 pm to midnight.

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 /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1227 AM CDT Fri Jun 12 2026

VFR conditions are expected for the TAF period. Light west/southwest winds and mainly clear skies are expected through the overnight hours. These winds will turn more out of the southwest for tomorrow afternoon with gusts strengthening up to 15-30 knots. Latest hi- resolution guidance shows showers developing north of I-90. Some uncertainty remains regarding precisely where the showers will develop and track along with the timing of the showers. For now, the best timing for these showers is the late afternoon and evening hours. Have not included mention of the showers in a TAF at this time but will include them once confidence increases. A few rumbles of thunder and gusty winds are possible in the showers as well. The weakening showers along with weakening winds will finish out the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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