All is quiet on the Illinois front this afternoon but attention is already turning back to the west where our system of interest is beginning to head in our direction. This continues to look like a fairly impressive event, especially for this early in the snow season and some areas across northern Illinois may end up seeing amounts of a half of foot. Also, the falling snow coupled with strong north winds and crashing temperatures tomorrow morning could make for a very treacherous morning commute across the area.....I dig into the latest below.
Our eventual snow maker is still well to our west and northwest this afternoon, located across southwest British Columbia and will be entering the Pacific Northwest later this afternoon and tonight. The strong shortwave will then dive ESE through Montana and into the northern plains by early tomorrow morning, eventually making its way into the Midwest just beyond that.
For a better visualization, you can see in the loop below our shortwave digging ESE through the northern plains late tonight/overnight and eventually into our region tomorrow morning.
Increasing large scale ascent from upper level divergence and gradual height falls from the digging upper trough will aid in precipitation developing and expanding into northern Illinois later tonight. Precipitation could initially start out as a rain/snow mix but will go over to all snow thanks to cold air advection as the low level cold air sinks southward. Through the morning hours tomorrow, a broad area of snow will also expand southward into central Illinois but we continue to pin point the northern part of the state for the highest snow totals. The loop below runs from 2pm today through 5pm tomorrow afternoon. Lastly, if you look closely in the loop below, you can see some darker blues showing up on the west side of Lake Michigan. With northeast surface winds, there could be some added lake enhanced moisture that leads to slightly higher snowfall totals near adjacent counties to Lake Michigan. Once snow begins late tonight across northern Illinois, it will continue into the early afternoon hours tomorrow until it ends from northwest to southeast as the area of snow sinks southeast through Illinois and Indiana.
With temperatures crashing well into the 20's during the morning hours tomorrow, this coupled with strong north winds and continued falling snow could lead to a very slow and snowy morning commute tomorrow. The loop below runs from 6pm tonight through 2pm tomorrow, showing temperatures dropping from north to south across the state with continued cold air advection.
Our latest thoughts on snowfall totals are below with the highest amounts running from eastern Iowa through the heart of Illinois, including the Chicago metro area. Lighter amounts will be possible as you go further downstate.