NWS: Sioux Falls under winter storm watch

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Sioux Falls has been added to the list of South Dakota areas under a winter storm watch as a "significant" snow storm moves through the area this week.

Sioux Falls could see as much as 10 to 12 inches of snow paired with ice, while areas like Brookings, Madison and Mitchell could see more than 18, the National Weather Service said.

"A good portion of South Dakota ... is going to get snow and wind," meteorologist Brad Adams said. Potential wind gusts could reach up to 50 mph in Sioux Falls Thursday.

A winter storm watch is in effect from late Wednesday through Friday morning in Minnehaha County. Blizzard conditions are possible. All counties in southeast South Dakota, except for Union County.

When will the snow start and end?

Adams said rain will begin to fall overnight on Tuesday and will turn to snow by Wednesday evening as temperatures drop. The heaviest burst of snow will likely happen Wednesday night, he said.

Accumulating snow is expected to cease by Thursday night, with a few final flakes falling until Friday morning.

What about flooding?

After the snow ends, temperatures are expected to rise into the 50s by early next week, Adams said. The warm-up, combined with significant snowfall, is a source of concern for flooding, especially since most river levels are still high.

"We're going to see increases ... back in the moderate to major crests," hydrologist Mike Gillispie said.

However, Gillispie says the flooding will not reach the levels seen in previous weeks, with most rivers cresting a half-foot to a foot below what they were in late March. The Big Sioux River at Dell Rapids, for example, is expected to crest at 15 feet, compared with the 16 feet it reached a few weeks ago.

Thawed ground also means some moisture will soak into the earth rather than accumulate on top of it, Gillispie said. Low overnight temperatures through the weekend will also help slow the melting process, with rivers not expected to crest until mid to late next week.

"It doesn't look as bad," Gillispie said.

NWS Daily Sioux Falls Forecast

Monday: Sunny, with a high near 70. Breezy, with a southwest wind 15 to 20 mph becoming northwest in the afternoon. Winds could gust as high as 30 mph.

Monday Night: Mostly clear, with a low around 41. Northwest wind 10 to 15 mph decreasing to 5 to 10 mph after midnight.

Tuesday: A chance of rain, mainly between 1 p.m. and 4 p.m. Mostly cloudy, with a high near 57. North wind 5 to 10 mph becoming east in the morning. Chance of precipitation is 30%.

Tuesday Night: Rain, mainly after 1 a.m. Low around 36. Breezy, with an east wind 15 to 20 mph, with gusts as high as 30 mph. Chance of precipitation is 80%.

Wednesday: Rain likely. Cloudy, with a high near 39. Breezy, with an east wind 20 to 25 mph, with gusts as high as 40 mph. Chance of precipitation is 70%.

Wednesday Night: Rain before midnight, then rain and snow between midnight and 1 a.m., then snow after 1 a.m. The snow could be heavy at times. Patchy blowing snow after 2 a.m. Low around 30. Blustery. Chance of precipitation is 90%. New snow accumulation of around 4 inches.

Thursday: Snow. The snow could be heavy at times. Areas of blowing snow. High near 33. Windy. Chance of precipitation is 80%. New snow accumulation of around 7 inches.

Thursday Night: A chance of snow. Areas of blowing snow. Cloudy, with a low around 27. Windy. Chance of precipitation is 50%.

Friday: Areas of blowing snow before 1 p.m. Mostly cloudy, with a high near 37. Breezy.

Friday Night: Partly cloudy, with a low around 24.

Saturday: Mostly sunny, with a high near 41.

Saturday Night: Partly cloudy, with a low around 26.

Sunday: Mostly sunny, with a high near 46.