Freezing Rain First

Update 11:30am = Thankfully, a large chunk of this batch of showers across the Stateline at this time is evaporating before it reaches the ground. This virga is keeping road conditions in a decent state. Some light sleet is being reported. You should still take it easy on the gas pedal as some driving conditions may change rapidly.

Original Post = This messy and massive winter storm is going to be causing travel problems from now through Tuesday night. A FREEZING RAIN ADVISORY (purple shading) has been posted for all WREX counties in northern Illinois. This is going to continue into this evening at which time our temperatures will hopefully rise above the freezing mark. Freezing rain is the worst case scenario for driving conditions. Sleet and even snow to some extent provides at least a minuscule amount of traction, but freezing rain turns area roadways into skating rinks. The batch of showers depicted on radar as snow is reportedly falling in the liquid form in the Quad Cities. Surface temperatures are still in the mid 20s as of 10am, which means most of these raindrops are going to freeze on contact. The afternoon commute appears pretty icy at this point so use caution as you head out.

The map above shows the large portion of the upper Midwest that this storm system is going to affect. Winter Storm Watches (blue shading) continue for Illinois counties along highway 20, but I expect this watch will be upgraded to a warning (pink shading) this afternoon.

With ExacTrack you can see in the image on the left (4am Tuesday) , there should be enough warm air moving in overnight to push the entire column of air above the freezing mark. The rain should be widespread and completely cover the viewing area. Freezing rain may still be a problem up in southern Wisconsin, which is why Justin will closely be watching our surface temperatures to monitor this situation. The image to the right is a still shot of 10am Tuesday. At that point, enough cold air on the backside of this storm system should move in to change all of our precipitation into snow. The snow appears moderate to heavy in nature from roughly 10am to 6pm.

As for the snowfall forecast (along the right hand side of the screen), I haven't changed it too much from what Justin posted last night. What I did do was shift some of the higher amounts to the north, but not by much. This is a very challenging forecast because there is going to be a sharp cutoff with the heaviest snow. Over a 30 mile stretch there could be as much as 6 inches of snow around Roscoe/Rockton, but as little as 1 inch near Rochelle. The models continue to flip-flop between snowfall amounts, which typically occurs. I usually lean on the track of the low to predict snowfall amounts. When an area of low pressure slides to the south of us between Oklahoma and Michigan, we normally get hit pretty hard. That is why with us still being 24 hours out from snowfall, I'm not going to stray from the 3-6" snow prediction for the Rockford metro.

In complicated scenarios like this one we use the terms possible and potential quite a bit, because a degree or two here and a track switch of a few miles there can cause major changes in the outcome. That is why you will want to bookmark this page over the next 24-36 hours as this event unfolds. -ADAM