ST. LOUIS – St. Louis area residents could wake up Saturday morning to the first frost of the season.

Jet stream forecast

The National Weather Service said, “Cooler air will move into the region to end the week, with temperatures dropping into the mid-30s for many locations Friday night into Saturday morning.”

The NWS said plant parents should have a plan to protect sensitive vegetation.

Meteorologist Chris Higgins says that the jet stream is expected to dip south. It will usher in the coldest air of fall, Friday into the weekend.

“Some of you may see your first decent frost over the weekend! The AC and furnace may be taking a break for now, but they need energy. Assistance knows no down time! Please remember our friends at Heat-Up St. Louis as we get ready for colder times ahead!” writes Higgins on Facebook.