Jan 31-Feb 1st - Sick of Snow?? Too bad! Several Inches of Snow On The Way For Portions of Illinois Tomorrow

For those who love the snow, we aren't done yet and this continues to be a pattern for snow lovers. Over the past several days, numerical model guidance has been showing a weak system moving through portions of the Midwest, including here in Illinois and producing a few inches of snow. Lately, the trend has been to move this system and swath of snow a little further north each model cycle run for the last 36 hours. This has led to places like the Chicago metro area looking to see more snow out of this than previously thought two days ago. 

A quick look into some details and timing below, as well as our thinking on expected snowfall totals..

Our system will take a similar track as our last one, coming ashore western Canada and quickly diving southeast into the northern plains by early tomorrow afternoon, as shown in the image below. It will then continue southeast late tomorrow afternoon and evening, entering the Midwest.

The driving mechanisms of this system are mostly aloft with really no hint of a surface reflection. The low amplitude wave will run along a tight thermal gradient, or baroclinic zone and help induce a fairly impressive period of warm air advection into our area. This will help in developing a fairly widespread area of light to moderate snow by tomorrow morning, initially to our west and northwest. You can see the strong warm air advection below in red, with the southwesterly winds aimed into Illinois below.

Snow will slowly overspread northern Illinois and portions of central Illinois beginning tomorrow afternoon, moving in from west to east and eventually reaching the Chicago metro area by the late afternoon and early evening hours. Once snow begins, look for it to snow over a given area for about a 6 to 8 hour period. Unfortunately, the timing of this does not look good for the Thursday late afternoon/evening rush hour across the region. The loop below runs from late tomorrow morning through 4am on Friday as the snow eventually departs much of the area after midnight tomorrow night.

The biggest problem of this event for travel is going to be the very cold temperatures across the area while snow is falling. The loop below runs from noon tomorrow through early morning on Friday. Temperatures across northern Illinois start off around or just below zero while rising into the single digits. A little further southern, temperatures attempt to get into the teens but either way, once snow begins to fall, it will stick and accumulate fairly rapidly given both the very cold temperatures at the surface and higher up in the atmosphere.

Much like we saw this past Saturday night across this same area, this snowfall will again be very light and fluffy, not like the wet and heavy snow.