KSDK -- A frost advisory has been issued for a large portion of the NewsChannel 5 viewing area for early Thursday morning.

A clear sky and light winds will allow frost to develop, especially over the eastern Ozarks into southern Illinois where it will be more widespread. Temperatures in the coldest areas will drop into the low and mid 30s.

Even around St. Louis, there will be some patchy frost early Thursday morning.

Another surge of chilly air arrives for the weekend giving some of us frosty mornings both Saturday and Sunday.