Weekend Storm Chances
by Kelly Smith, Meteorologist
December 03, 2011 12:00 AM
Snow showers are beginning to taper off and move out of our area. Visibilities are still low in some locations, mainly in northwest Iowa where snow continues to fall. The snow should give way to mostly cloudy skies by later tonight. Roads still remain slippery in many locations, including Sioux Falls where around .2 inches was reported, however, close to an inch of snow fell in the east-southeast side of town. Preliminary reports show two inches of snow fell in Vermillion and three and a half in North Sioux City. Temperatures will remain below freezing overnight; so even the snow will come to an end the roads will still remain slick. Wind speeds remain fairly low at around 5 to 15 miles per hour, but keep in mind it does not take much to blow the snow around. The image to your left is from North Sioux City taken late Saturday afternoon. Winter Weather Advisories remain in effect through 12AM Sunday CST, and are the counties shaded in purple.
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This particular system has been very difficult to forecast as the weather models we use to forecast have differed significantly in the forecasted track. As we get closer to the event, the models should come into better agreement on the exact track and intensity. Slight changes with this storm mean very large changes. For example, if the track were to change by even 30 miles that would effect almost two hundred thousand more people than it currently affects.Our in-house weather model: Futurecast brings the system just south of Sioux Falls. This track would bring the majority of the heavy snowfall into portions of Iowa exactly where the Winter Weather Advisories have been issued. As for timing, Futurecast has the first snow flakes falling by 10am Saturday.
(Futurecast Valid Saturday 12pm CST)As the day goes on another wave of snow will move north and increase the snowfall band to the north and west.
(Futurecast Valid 6pm CST Saturday)Futurecast brings the band of snow north just south of I-90, but large accumulations are not expected in Sioux Falls and as of now it looks cold enough that any and all precipitation will fall as snow.
(Futurecast accumulations)Snow fall smounts will differ from one location to another and it is quite possible that the snow band that does set up will be very narrow. A narrow snow band could bring one location quite a bit of snow while another a short distance away could possibly see only flurries. Snow storms also tend to "wobble" and if this system makes any slight changes it could mean a large increase or decrease in snow amounts. Keep in mind that Spencer, Iowa is around 80 miles away from Sioux Falls and if the snow storm moves even 40 miles to the northwest Sioux Falls would see quite a bit more snow. However, the opposite is true as well, if the system moves 40 miles southeast Sioux Falls could very well not see any snowfall.This storm system has the potential to effect quite a large area, but notice almost the entire state of South Dakota will remain dry as the system looks to move farther south
(Snow Totals)As with any storm, the weather is constantly changing. If you do have travel plans in and around Iowa keep an eye on this system as it has the potential to cause many travel issues. We are keeping a close eye on this system and will update as needed.Follow KDLT Weather on Twitter for Updates and Storm Reports.