A frost advisory has been issued for the northwestern two-thirds of Iowa by the National Weather Service.

Overnight lows will dip into the low-to-mid 30s, and frost is possible from the early morning hours to 8 a.m. The Frost Advisory includes Warren, Polk, and Jasper Counties locally — however, patchy frost is also a possibility across Marion, Mahaska, and Lucas Counties.

Typically, the first frost of fall is between September 27h and October 2nd across south central Iowa.

Brisk conditions are expected to continue through Sunday, with afternoon highs in the upper 50s and overnight lows in the upper 30s over the weekend. Warmer air returns Monday, with highs approaching the low 70s by the middle of next week.