Some minor changes to the storm system that will greatly impact portions of the plains and Midwest. A strong low pressure system is currently settled near western Nebraska. This low pressure system will continue to strengthen and track through Kansas into Missouri and then right over the Stateline area. With this current set up in place, some of the heaviest snow will be situated west and north of the Stateline area.
For northern Illinois and southern Wisconsin there are currently Winter Weather Advisories for Jo Daviess, Rock, and Green counties beginning 3am Tuesday through 6am Wednesday morning. These counties have the highest probability to see higher accumulations of snow as well as sleet. For the rest of the Stateline, not much snow is expected, maybe an inch or
so. While areas under the Advisory could see 1-3" and locally higher.
Just west and north of the Stateline however is where the Blizzard conditions are forecasted to take place. The pink shading indicates Winter Storm Warnings, the red indicates Blizzard Warnings, and the neon green indicates Blizzard Watch. These areas look to see significant snow and sleet pile up, as well as the hazard of blowing snow.
Breaking down what you can expect in the Stateline: After midnight tonight areas of snow, sleet, and possible rain will lift north and east from Iowa into northern Illinois and southern Wisconsin as temperatures start off just below freezing. It will start on the patchy side and then begin to increase in coverage. The winter mix will then slowly transition to all rain between 8am and 10am as temperatures rise above freezing. Periods of rain will continue through the afternoon before a dry slot develops and helps to bring some of the precipitation to an end. As the low transitions from being over the area to then the north east, the rain will then transition to a winter mix as cold air is pulled in behind the low pressure system. We could even see this turn to all snow late Tuesday through early Wednesday. The system will be losing moisture, so the snow looks to stay light into Wednesday morning. The totals as discussed above would be including what falls Monday night through Wednesday morning.
This is a very dynamic system and has lots of moving parts. The track of this system could continue to change a bit but overall the take away from this will be to prepare for messy driving conditions late tonight and early Tuesday morning. Areas in southern Wisconsin and far north western Illinois look to see more measurable snow fall, over a couple inches, while southeastern counties look to see a lighter mix and turning to rain sooner.
The First Warn Weather team will continue to update you and keep you posted on what to expect!