Even Colder Air This Weekend?

Temperatures of late have been very cold across the region. Sunday was spent in the single digits, Monday was spent in the teens, and today has featured highs near 10°. This evening, temperatures are dropping into the single digits with wind chills remaining well-below zero through the entire night. With the coldest stretch of weather thus far this season affecting the area, a popular question has been, "How much longer will it last?" There is a light at the end of the tunnel to end this week, but soon thereafter, arctic air will move back into Northern Illinois and Southern Wisconsin.

Temperatures on Wednesday will reach the lower 20's before warming into the balmy 30's on Thursday and Friday. Some locations south of Rockford may flirt with 40° on Friday. With that system comes some rain and snow, but snow accumulations look light at this time with much of the moisture from our system being pulled to the East Coast where a stronger low is going to develop.
The coastal low is going to take some moderate to heavy rain and snow into the Northeast and New England on Saturday. The more important story for the Stateline regarding this weekend's storm system is the reinforcement of arctic air that will stream southward from Canada on Saturday night. Each time a low pressure system passes by, the winds turn northerly, and that allows colder air to filter into the region. This explains why each time we see snow associated with a low, it typically gets colder after the snow comes to an end. That will hold true this weekend, but the colder air may be even colder than what we have now.

This next arctic air outbreak will likely bring low temperatures in the 10° to 0° range for a string of 2-3 mornings. It also appears as though forecast models want to bring down enough cold air to hold our daytime highs in the single digits on Sunday and Monday. However, it is important to note that we are still a good four days away from this arctic plunge. Therefore, things have time to change, which means the magnitude of the cold air could decrease, meaning temperatures may not get quite as cold as currently advertised.

Nonetheless, it does look like a reinforcing shot of arctic air is likely this weekend into next week with air that is as cold as what we are experiencing now, if not colder.