A strong Colorado low-pressure system will bring an outbreak of severe thunderstorms and even tornadoes to the southern regions of the United States. On the northern end of the storm system, back towards home, we will see strong winds pull cooler air, giving us a chance of wintry precipitation for the first part of the work week.
Starting Monday night, rain is expected to develop over southern and eastern regions of South Dakota. You cannot rule out a thunderstorm over the far south. By Tuesday morning, cooler air will push behind the precipitation, changing the rain over to freezing rain, a wintry mix, or snow.
By the start of Tuesday afternoon, cooler air will continue to filter into the state, changing the rain over to a wintry mix or snow for the west and northern parts of South Dakota before becoming all snow by Tuesday evening.
The bulk of the snow is expected to exit out of the state by Tuesday night. A few isolated snow showers are possible along and east of Interstate 29 for early Wednesday morning.
There are many factors that still need to be worked out with this system on when the precipitation will change over to snow. The forecast models do not completely agree on the forecast snowfall amounts, with the EURO (ECMWF) model showing snow amounts under one inch for the most part, with a few higher amounts across the northeast and parts of the southwest and south-central regions of the state. The American (GFS) is being bolder on snow amounts in the southwest, bringing several inches of snow to that region and a little bit more in parts of the northeast. The Candian (GEM) model is going against the American and EURO models, showing more significant snow in the region.
Besides the snow, strong winds will be pulled into the system, bringing the risk of blowing snow and even possible blizzard conditions. Wind gusts up to 50mph are possible for parts of south-central and southwest and gusts up to 40mph for the rest of us.
Winter Storm Watches are already in effect for southern parts of South Dakota. Keep checking back with WeatherSD for additional information on this storm system.