It continues to look like winter and a cold snap will return to the Midwest next week but model guidance continues to differ on exact solutions regarding how long it will last along with just how cold it will get....I dig into a brief update on the latest thinking below...
Numerical model guidance is in agreement on a weather system of some fashion developing and moving through portions of the Midwest early next week, most likely leading to another day of above normal temperatures on Monday across Illinois. It is what transpires after that which is in question. A trough should develop over the northern U.S. into our region but the strength and depth of that will determine just how cold we get next week. You can see the evolution of this below. This loop runs from Sunday night through next Tuesday night, showing the trough situating itself over our region.
Just for some basic understanding of meteorology, below is a representation of a trough and a ridge and the shape of them usually. As you can see in the above loop, a trough is the main feature. Usually active weather and below normal temperatures are associated with a trough while more quiet and dry weather and above normal temperatures are associated with a ridge.
Looking at actual surface temperatures from just *ONE* model (saying this as things could change), we can see the very cold air invading the state of Illinois late Monday night and Tuesday morning behind the cold frontal passage. This model continues to say that areas across the northern part of the state could get well into the single digits on Wednesday morning with teens likely for the rest.
With several things remaining in question regarding this shot of cold air, expect more updates in the future as we get closer to next week....