We are less than 24 hours away now from snow impacting Illinois as model guidance tries to get a better handle on this system as we get closer. We are still expecting widespread snow accumulations across portions of the state, as you'll see below. Let's dig into the latest.
Our two systems of interest our inching closer with the northern stream wave moving through British Columbia this afternoon with its sights set on crossing the Rockies tomorrow morning and afternoon. This will eventually phase with the slowly meandering southern stream upper level low that is still located across southern Arizona and the Baja region of Mexico. This will continue slowly through the southern plains and eventually turn more northeast heading in our direction.
We can see the entire evolution of this system below....widespread precipitation, in the form of snow on the north and northwest side will streak northeast out of the plains into portions of Illinois by tomorrow afternoon, continuing northeast into the rest of central and northern Illinois by early tomorrow evening. Snow will continue much of the night across about the northern half of the state and then slowly winding down from west to east Thursday afternoon. A secondary disturbance associated with the much colder air could aid in snowfall production continuing into the afternoon hours across northern Illinois and near Lake Michigan.
By early Thursday morning, an arctic front will be plowing eastward across much of the state, ushering in much colder temperatures as you can see on the image below. Snow should still be ongoing across northern portions of the state at this time leading to the snow becoming light and fluffy, accumulating easier and also an increasing chance for blowing and drifting snow Thursday morning and afternoon as strong northwest winds arrive behind the frontal passage.
Here is our latest thinking on expected snowfall totals across the state. Stay tuned for continued updates.