It won't be as intense as the cold that descended upon the Stateline late last week, but an incoming blast of arctic air is to send temperatures into the single digits for at least the next three nights, with below zero readings not to be ruled out.
Though temperatures Tuesday topped out near or even slightly above normal in the Stateline, they're falling quickly thanks to an increasingly well-organized northwesterly wind. By late Tuesday Evening, many Stateline communities were reporting temperatures in the teens with single digit wind chill values. By sunrise Wednesday, most spots will have seen temperatures fall into the single digits, with a few sub-zero chills likely here or there.
Despite nearly unlimited sunshine Wednesday, temperatures will struggle to reach much above the mid-20s in most spots. As high pressure continues to drift closer to the Stateline, winds will relax Wednesday Night, allowing temperatures to cool even more efficiently. This will provide the greatest potential for temperatures to fall below zero in a few communities, though a scattering of high and mid-level clouds may be just enough to keep temperatures right around 0° in the City of Rockford proper.
An unseasonably strong Canadian high pressure system will pass directly overhead Thursday, placing the heart of the cold air over the Stateline at that time. Temperatures in many of our hometowns may not even reach 20°. As the high slides off to the east Thursday Night, winds begin to shift to a more southerly direction. Initially, temperatures will plummet into the single digits, but should begin to rise overnight as those southerly winds lock in.
From there, a gush of Pacific air is to ride into the area as the jet stream realigns. This should send temperatures to much more seasonable levels Friday, and will promise a much warmer weekend with highs in the 40s both Saturday and Sunday.