It’s been a pleasant, if quiet Sunday but changes have been brewing for awhile and are set to move in tonight. There are a few patches of clouds and rain showers coming in from the SW and more rain will come in south of I-90 by late this evening. This approaching storm will be the big weather story for the week to come.
An Areal Flood Watch remains posted, and, as expected, it now goes through late Tuesday. There’s also an unchanged Winter Storm Watch, in place for the Black Hills. In some spots, we could see a fresh 6-12” of snow. This will be aided by strong and cold Canadian winds, and the lift from the Hills themselves. As we’ve been saying for almost a week, the heaviest moisture will be East River, near the Highway 14 corridor. This means areas like Brookings, Huron, Watertown, Pipestone and Marshall. Almost everything tonight will be regular rain tonight. The heavier stuff looks to move into central and south-central SD tonight and could reach Sioux Falls between midnight and sunrise. If you have early outdoor plans, they should be fine. The change-over to snow (for the Black Hills) will come later tomorrow afternoon as winds strengthen. The system will really tighten up right over South Dakota, due to the jet stream’s position just south of the state.
Drier air moves in from the south early on Tuesday. The surface part moves out due east, which is slightly unusual. The past few have headed NNE. That could add to some additional rainfall totals for those in Iowa, SE SD, and Minnesota. The low pulls off towards the Great Lakes late on Tuesday. Cooler than average air sticks around the rest of the week but we’ll have plenty of sunshine!