SIOUX FALLS, S.D. (KELO) — The temperatures will be perfect for sweater-weather, but at what cost?

It is set to be a wet weekend as we enter into fall on Saturday, September 23. Storms are in effect as this is being written, and will continue to circulate throughout the weekend, bringing rain, thunder and chances of hail.

Already in the southwestern South Dakota things are kicking off, with Pennington, Oglala Lakota and Fall River counties under a severe thunderstorm watch. This will be in effect till 9:00 p.m. mountain time, and brings the threat of large hail, strong winds and pockets of heavy rain and possible tornadoes.

Storm warning in effect for Friday, September 22, 2023

By 5:00 p.m. on Friday, that storm system will have pushed itself into the center of the state, stretching from Mission, up to Mobridge and over toward Bison as smaller systems begin to enter the state near Belle Fourche and Edgemont.

Friday, September 22, 2023

Those smaller systems will shrink and vanish as they head northeast into the state, though Pine Ridge may see some action from the smallest one before it dissipates.

By 10:00 p.m. the system will be mostly east of the Missouri River, hitting an area from Highmore to Ipswich while still stretching back to cover Herreid and McLaughlin.

Friday, September 22, 2023

Just as that system finally pushes most of the way out of South Dakota, with some action left southeast of Aberdeen, the southwest portion of the state will be bracing once again for another round.

This will enter the state around midnight, and by 2:00 p.m. it will be directly over the Black Hills region, stretching east as it prepares to roll through the state.

Early Saturday morning outlook

By 7:00 a.m. Saturday this system will have ballooned outward, stretching from below Valentine, Nebraska, up to Eagle Butte and back to Buffalo, with heavy rains and hails possible in spots throughout.

7:00 a.m. Saturday, September 23, 2023

By 8:00 a.m. on Saturday, the system is projected to split in two, with the top half drawing up to sweep over Eagle Butte and Pierre, while the lower cell will power through toward Yankton, Mitchell and Sioux Falls, bringing heavy rain and large hail.

By 11:00 a.m., the system will have reached Madison, Brookings and Watertown, and we could see the two systems start to recombine, stretching across the northern reaches of the state in a low arc from Buffalo all the way to Sisseton and down to Luverne, Minnesota as the day passes into noon.

Saturday, 8:00 a.m. to noon

From noon to midnight on Saturday, things will begin to clear out for much of South Dakota, as the system pushes north and east, though a concentration of activity seems intent on spinning around the Aberdeen area.

Saturday, noon to midnight

Come Sunday morning, most of the activity will have left South Dakota.

Overall, much of the state will expect to see between 0.5 to 1.25 inches of rain, though the Cheyenne River Sioux Reservation will receive much more; potentially up to 3 inches.

Weekend precipitation through Sunday

Despite being the area through which most of these systems enter the state, the southern reaches of South Dakota can likely expect less than half an inch overall.