Winter Storm Warning in place for the Stateline area, for our western counties until 6pm Sunday and 12am Monday for the rest of the area.
Snow has developed west of the area and has been tracking east through the afternoon and early evening. So far Rockford has seen 1.5" of snow. Currently there is a bit of a lull with clearing taking place west of Rockford, but we aren't done with the snow just yet. We do expect snow to pick up this evening, and we will notice moderate to at times heavy snow falling. Visibility will drop quite a bit in the moderate and heavy snow bands.
Timing out the snow, a good chunk of it will fall overnight tonight and early tomorrow morning. Anywhere from 3-6" will be on the ground Sunday morning, with an additional 3-6" through Sunday afternoon. The snow Saturday evening and early Sunday morning will be drier and more powdery because it will have a high snow to liquid ratio. With gusty southerly winds
overnight this will create a blowing snow and a low visibility hazard. Of course you will also need to watch for roads that are slick and snow and ice covered. By Sunday afternoon with temperatures in the low 30's the snow will turn wetter and slushier in nature, which will make it harder to blow around but also harder to shovel.
In total about 8-12" of snow will fall between Saturday afternoon and Sunday evening. With totals dropping quickly south of I-80.
Here is a quick check at road conditions, but for more of an updated version click here. While travel will be hazardous through Saturday night and Sunday, it will be a lot better by Monday morning with snow ending by Sunday night.
A low pressure system is currently settled in the central plains with a warm front extending through Iowa and northern Missouri and into central Illinois. Surface winds are out of the south, which draws in a lot of moisture from the Gulf of Mexico. As we go up in the upper levels of the atmosphere, the jet stream is positioned overhead and is oriented somewhat zonal - or moving from west to east. The jet stream intensifies over the Great Lakes region, what that means for us is that we are in the right rear entrance region of the jet stream. Essentially this means we are in an area with enhanced lift, and when you combine that with added moisture, and then additional lift from the transportation of warm air nearby, you get enough ingredients to support snow fall.