Winter storm arrives this weekend bringing heavy, wet snow

Published: Mar. 12, 2021 at 6:44 PM MST
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RAPID CITY, S.D. (KEVN) - Models are starting to come together, but there is still a lot of uncertainty with this storm system. To show that no forecast is a guarantee, Denver is expecting much less snowfall totals than what they were thinking in the previous days. This is why I have held off from showing snow totals for so long - until now. Winter Storm Watches and Winter Storm Warnings are in place from Saturday night through Monday morning.

For those in the watch, you can expect the potential for 6″+ of snowfall. The watch is for the Wyoming Black Hills, northern foothills (Spearfish), Sturgis/Piedmont foothills, Rapid City and areas to the south and east. This is where things are more uncertain for multiple reasons, which I will explain soon. The warnings are for those in the Black Hills and south through Fall River County. Southern Campbell County is also in a warning, which includes the city of Wright. Those places can expect 8″-16″+ of snow. These spots are more certain because of the higher elevation, which means colder temperatures and a longer duration of snowfall.

Rain is expected to move into the area Saturday afternoon and evening. The changeover to snow will be quick for those in the higher elevations of the southern/central hills. Moisture will continue to pour in through the night. Rain will continue for much of the night for the lower elevations, while snow falls for much of the Black Hills. The make it or break it part of the forecast is just how quickly the rain changes over to snow for those at lower elevations. If it occurs in the morning around daybreak, you can expect significant snowfall totals. If it occurs midday or during the early afternoon, you can expect much lower snowfall totals. This will be something for you to keep an eye on for when you wake up Sunday and go about your day. If it snows early on, it would be best to stay home and avoid the roads.

Highest accumulations will be in the Black Hills. 10″-16″ or higher look to be likely from Lead/Deadwood down through Deerfield, Hill City, Custer and into Hot Springs. Travel impacts will be the highest in these locations. Snow covered roads with some ice underneath from initial melting. The southern plains along the Nebraska State line from Pine Ridge to Martin could see anywhere from 6″-12″ of snow with higher amounts possible. The uncertainty mentioned above is more for Spearfish, Sturgis, Rapid City and Pennington County. The northern foothills could see 4″-8″ of snow with higher amounts possible. Rapid City will see around 5″-10″ of snow. Higher amounts are expected if rain changes to snow early in the morning. Remember, many of these snow totals are subject to if the changeover happens early or late in the day. If the changeover to snow is earlier in the morning, expect totals to be near the higher end of the range. Like I said above, if the changeover is later, say midday to early afternoon, you can expect snow totals probably less than 5″.

Travel will be very difficult with reduced visibility and slippery roads - especially in the hills and southern plains. Power outages are possible with this storm system as heavy wet snow could snap some tree branches and hit power lines. it will be breezy with gusts ranging from 30-40 mph. While visibility could be significantly reduced at times, this will not be anywhere near a blizzard. For that to happen, sustained winds will have to be 35 mph or higher and visibility will need to be 1/4 of a mile or less for three hours or longer. We’re not expecting anything close to this with the storm this weekend.

This is our preliminary snowfall forecast. Since the snow doesn’t really start to fall Saturday night and Sunday, there will and mostly likely will be changes to the snowfall map through the day Saturday. Because this is an ever-changing forecast so stay tuned for updates through the day Saturday, up until the moisture begins to move into the area.

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