textproduct: Sioux Falls

KEY MESSAGES

- A Red Flag Warning is in effect for most areas through 8pm. Avoid any outdoor burning as a fire could quickly spread out of control!

- Scattered thunderstorms are likely west of the James River later this evening and overnight. Isolated strong to severe storms are possible.

- Isolated severe storms are again possible Thursday afternoon over parts of southwest MN and northwest IA, especially along and east of Highway-60.

- A return to more seasonable temperatures with highs in the mid 50s to lower 60s is expected Friday through the middle of next week.

- A very good chance (30%-60%) for showers and thunderstorms returns Sunday into Monday. Some locally heavier rain will be possible.

DISCUSSION

Issued at 109 PM CDT Wed Apr 22 2026

Strong winds will continue into the evening, but the lower humidities will diminish around sunset. It should be noted however that fairly strong southerly flow will continue through the night. Otherwise, a cluster of showers and thunderstorms will become likely in central SD later this evening into the overnight hours. With 1000-1500 J/kg CAPE potential and some drier low levels hail to the size of half dollars and wind gusts to 65mph will be possible. These storms should be confined to areas west of the James River and possibly mainly closer to the Missouri River in central SD. The weak mid and upper level wave associated with this development drifts east through the night, but instability wanes towards I-29, so expect any stronger storms to generally weaken as they head east late tonight into early Thursday morning.

The late tonight and early morning activity will diminish through the morning, but given the amount of clouds left behind as well as the progression of the pre-frontal trough, the threat for severe weather seems pretty limited for Thursday afternoon and likely shifted a bit east. For now, the best chance for isolated severe storms will be mid to late afternoon and mainly east of a Marshall to Sioux City line. If we can break out of the cloud cover and warm enough, there will be about 1000 J/kg CAPE with about 30 knots of shear so the potential for half dollar hail and 60 mph winds will exist.

Friday looks cool and dry with winds remaining mostly below 15 to 20 mph, so not too bad of a day. Highs mainly in the 60s.

On Saturday, low pressure to the northwest will drift east but not move very much, as jet energy wraps around the southern edge into the area. Saturday into Sunday a southern stream jet will also spread into the Central Plains and bring additional upper level support to the area. What this means is that from roughly Saturday into early Monday the area will see periods of moderate to strong mid level warm advection, which will bring periodic chances for showers and thunderstorms. The strongest period of lift appears to arrive on Sunday but for now the various models focus is all over the place so confidence is a bit low on the exact location of the more organized showers and storms. Of note the canadian ensemble and ec ensemble indicate most of the area will see a 60-90 percent chance for a half an inch or more of rain while the GEFS indicates something similar, just to the southeast of the area. Probabilities of an inch or more are running about 30-40 percent. Long story short, will need to watch trends to see if we can really get some meaningful rainfall in the area.

Low pressure wraps up to the north Tuesday into Wednesday, leaving the area in faster west to northwest flow and likely mostly dry conditions. There will be some spotty chances for showers and thunderstorms but for now that looks like a very isolated threat. Temperatures will be near the seasonal normals.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1215 PM CDT Wed Apr 22 2026

Southerly winds will gust to 35 to 45 mph into the evening. Scattered thunderstorms are likely near and west of the James River later this evening into the overnight. While the storms will weaken, scattered showers and isolated thunderstorms will be possible east of the James River on Thursday morning. Later tonight into Thursday morning, MVFR and possibly IFR ceilings will develop with the better chances in northwest IA.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning until 8 PM CDT this evening for SDZ038>040- 050-052>071. MN...Red Flag Warning until 8 PM CDT this evening for MNZ071-072- 080-081-089-090-097-098. IA...Red Flag Warning until 8 PM CDT this evening for IAZ001-002- 012. NE...Red Flag Warning until 8 PM CDT this evening for NEZ013-014.