Very chilly Friday in store across Chicago area

Brisk northeast winds will prevail Friday as the leading edge of cool high pressure builds into the western Great Lakes and Chicago area. A very chilly day is in store here — perhaps the coldest day of the month so far.

With on-shore flow holding readings in the 40s along and inland of the lakefront, and with expected highs in the lower 50s well inland, a 24-hour high temperature swing of 20 to 25 degrees is likely from the lower 70s Thursday to the upper 40s and lower 50s Friday.

Some patchy light frost may occur late Friday night/early Saturday morning to the west and north of the city in the Fox and Rock river valleys.

It will still be chilly Saturday. On Sunday a more southerly component to the winds finally will allow readings, especially inland, to warm well into the 60s.