Temperatures expected to drop into the upper 20s to lower 30s across the Chicago area – Frost Advisories/Freeze Warnings in effect from 1AM to 9AM CDT later tonight into Friday morning
Frost and Freezing temperatures are expected to occur later tonight and early Friday morning across northern Illinois into northwestern Indiana. Sensitive outdoor plants and vegetation will be killed unless protected or brought indoors.
A Freeze Warning for temperatures in the upper 20s to lower 30s will be in effect from 1AM to 9AM CDT tonight and Friday morning for Winnebago, Boone, McHenry, Ogle, Lee, DeKalb and Kane Counties (dark-blue-shaded area on the headlined map). A Frost Advisory for temperatures in the low to middle 30s is in effect for basically the remainder of the Chicago area into northwest Indiana including the city of Chicago and Cook County (lighter-blue-shaded area on the headlined map).
Strong west to northwest winds will continue to push colder air into our area today – winds will weaken tonight, as the center of cold Canadian-source high pressure approaches out of the central plains. Clouds will gradually recede off to the east later this afternoon with clearing skies expected tonight. Temperatures will likely struggle to reach 50-degrees this afternoon and thus a simple drop of 15 to 20-degrees will set the stage for frost and freezing temperatures. In the Frost Advisory areas, colder spots could also drop down into the upper 20s.