Area Forecast Discussion

KEY MESSAGES

- Showers will move across the area through early afternoon, with a few thunderstorms possible east of I-29. Severe weather is not expected but brief heavy downpours are possible.

- Additional showers and a few non-severe storms are possible north of I-90 this afternoon. Isolated wind gusts to 40 mph may accompany storms, and there is a non-zero chance of weak funnels with developing showers or storms this afternoon.

- 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.

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

UPDATE

Issued at 425 AM CDT Thu Jun 11 2026

Cluster of severe storms is remaining well to our south so far this early morning, but will continue to watch for potential of a few stronger storms along the elevated warm front which looks to be encroaching on the Hwy 20 corridor as of 4 AM. Latest CAMs remain consistent with keeping the severe threat south of our forecast area as the growing MCS tracks east along the I-80 corridor, but isolated small hail or gusty winds may develop with stronger updrafts from Sioux City to Storm Lake early this morning.

Farther north, we'll see a broad area of mainly light rain move east across the forecast area through midday-early afternoon. As this clears to the east, a compact upper wave could trigger scattered showers or a few weak thunderstorms toward Highway 14, and perhaps as far south as I-90 during the mid-late afternoon. Severe weather is not expected due to limited instability. However, RAP continues to show a pocket of enhanced stretching potential beneath the wave, so cannot rule out a weak funnel during the developing stage of showers. NBM seems on the high side of guidance with highs today considering the influx of cooler air with the aforementioned wave, so nudged our highs down a few degrees, especially where the showers could occur north of I-90 this afternoon. With this, some locations may struggle to reach 70F, with some solutions keeping these areas in the mid 60s.

No significant changes beyond today in the forecast. We will see a brief warm-up Friday before another shot of cooler air spills into the region this weekend. This looks to hang around through the first part of next week with highs in the 70s to lower 80s Saturday through Tuesday on the cool side of normal for mid June. More notable than the cooler temperatures, though, is the relative lack of humidity through much of next week. Dew points in the 40s, or even some 30s, are highly favored for the weekend through Tuesday, with ensembles showing less than a 20% chance of dew points exceeding 50F during this period.

As far as rain chances, we could see scattered showers/storms develop in southwest Minnesota Friday evening, with chances in northwest Iowa during the day Saturday. Given the drier air noted above, heavy rainfall is not expected and severe weather risks are low in both cases.

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 /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 640 AM CDT Thu Jun 11 2026

Off and on showers will move east across the forecast area through 18-19Z, with a chance for additional spotty showers or storms toward Highway 14 and into southwest Minnesota mid to late afternoon. Expect thunder to be isolated at best, so have no mention of that in the TAFs. However, heavier showers may produce MVFR-localized IFR visibility at times.

Behind the main area of showers this morning, will see west to northwest winds gusting 20-30kt, locally higher. Any showers or storms this afternoon will also be capable of brief erratic gusts up to 35kt.

Any showers and gusty winds are expected to diminish by sunset with VFR conditions and light west winds through the end of the TAF period.

FSD WATCHES / WARNINGS / ADVISORIES

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