After a very warm start to the week, the weather will be changing dramatically late in the week as a major storm system approach is the region. In the short-term forecast, today will be a pleasant day with highs in the 70s and breezy winds from the northwest, especially in northern South Dakota. Quiet weather trends will continue for most areas tonight with lows between 45 and 50. However, there could be a few scattered thunderstorms in northwestern South Dakota overnight. Tomorrow will feature increasing clouds and the chance of shower and thunderstorm activity late in the day and into the evening, mainly in eastern KELOLAND. Sioux Falls could make it up to 80 in the afternoon, while Rapid City will be cooler only in the upper 60s with north winds.
The weather forecast gets more unsettled as we head towards Thursday and Friday. Areas of showers and thunderstorms are likely on Thursday. Sioux Falls will still have a chance to hit 70 degrees, but much cooler 50s will be filtering into western South Dakota. In fact, the colder weather will continue to get progressively worse into Friday as rain changes and mixes with snow in eastern Wyoming, western Nebraska, and parts of the Black Hills Thursday night into Friday.
This storm system will become very strong on Friday as the center of low pressure travels just south of KELOLAND. Rain will be likely in most areas, with snow possible in the northern Black Hills. To our south, severe weather will be possible across much of Iowa on Friday. As the storm system passes through the region Friday night into Saturday, sharply colder winds of 25-50mph will accompany cold rain which may mix with or change to snow through Saturday morning in parts of KELOLAND. At this time, we can only speculate as to how much snow will occur.
We do get snow in early October here every few years, so this certainly something to watch. The most aggressive solution for snowfall for much of our area comes from the European model, which has shown more accuracy with these types of storms. With or without snow, highs into the 40s on Saturday will feel very cold and there is a good chance of a frost or killing freeze Saturday night, especially in the northeast. More details later today.