textproduct: Sioux Falls

KEY MESSAGES

- Late tonight into early Thursday morning showers and thunderstorms are expected to develop across the region. Storms will move east through early afternoon Thursday.

- A few strong to severe storms may develop early Thursday morning (5-9 am) for portions of northwest Iowa. Isolated wind gusts to 65 mph and hail up to ping pong ball size would be the main threats.

- Friday through the first half of next week will see cooler highs in the 70s to 80s and lower relative humidity values.

- Saturday will see a chance of thunderstorms over mainly northwest Iowa. At this time severe risk appears to be low.

DISCUSSION

Issued at 147 PM CDT Wed Jun 10 2026

A cold front draped from central Canada south through the central Plains will gradually make its way east through the afternoon today. To the east of the front an influx of moisture advection will work to destabilize the atmosphere. As the upper wave passes over the cold front it will work as a focus for shower and thunderstorm initiation. Short term guidance is in fairly good agreement that any stronger storms will be well east of the region into central Iowa this afternoon and evening, where the better dynamic setup is. One thing to watch this afternoon is a band of vorticity advection and enhanced stretching potential that could result in brief funnels late this afternoon for areas along and east of Highway 60. If any funnels form they should be weak and short lived.

Late Wednesday night into early Thursday morning an area of weak WWA coupled with an increasing LLJ swings through central South Dakota. This may trigger showers and thunderstorms. These storms will progress northeast through early Thursday afternoon. Instability is low, less than 500 J/kg, but could be enough for a few lightning strikes. For areas north of Highway 18, severe weather is not anticipated, however a few brief, heavy downpours are possible. Around daybreak a surface low will move northeast out of central Nebraska. Instability will rapidly increase ahead of the low as 0-6 km Bulk shear ramps up 70-75 kts. In addition, synoptic support in the form of a jet streak right entrance region, a mid-level trough axis, and continued intensification of the LLJ may work to focus storms into a more organized area of supercells. These will then quickly grow upscale into a mesoscale convective system (MCS). There remains some uncertainty in the track of the low, with most guidance keeping the initial stronger supercells just to the south of our CWA. However, a few bring isolated strong to severe supercells into our northeast Nebraska counties and into northwest Iowa, mostly east of Highway 60. These stronger storms will be capable of producing hail to ping-pong balls and wind gusts of 65 mph. As the strongest storms are expected during the morning commute, roughly 6 - 9 am, we will need to monitor the trends. Any lingering showers and thunderstorms should be east of the CWA by the early afternoon. Highs Thursday afternoon will be cooler thanks to CAA behind the wave, in the 70s.

Mostly zonal flow aloft and dry conditions are expected for Friday. At the surface west winds become southerly through the day. A strong push of WAA will warm afternoon highs in to the 80s and 90s. Friday overnight a weak cold front pushes through the region, brining low chances (<25%) of rain to areas along and north of Highway 14. As the front progresses to the southeast there will be additional low to medium chances (<40%) for light rain over portions of southeast South Dakota, northeast Nebraska, and northwest Iowa from roughly daybreak through the afternoon. Highs Saturday will be slightly cooler in the upper 70s to mid-80s. Northwesterly flow in the mid- levels keep cooler temperatures in the forecast for Sunday as well, with highs in the low to mid 70s. This trend of 70s for highs continues into the first half of next week. Dew points during this time will also be lower, in the 40s to low 50s. If you have any outdoor projects, this would be a great time to work on them without the heat and humidity.

Monday night into Tuesday a strong upper wave will work through the region bringing chances of rain to the area. Details on instability and potential for strong storms are uncertain at this time.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 635 PM CDT Wed Jun 10 2026

VFR conditions begin the TAF period. Latest satellite shows a weak CU field that is beginning to dissipate early this evening. This will leave quiet conditions for the rest of the evening hours. Chances for rain will increase over the course of the overnight hours, with the highest chances for rain (50-70%) coming across parts of northwest Iowa, especially just east of KSUX. Thunderstorms are possible around KSUX as well but confidence is too low to include in a TAF at this time. Rain looks to last through the morning hours before exiting during the afternoon timeframe. Ceilings are expected to remain at VFR levels though visibilities could drop to MVFR thresholds in falling rain. A few showers could persist for the rest of the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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