WDEF-TV News 12 Tennessee River Valley weather forecast Overnight: Partly cloudy. Mild. Isolated thunderstorms. Lows: high 60's. Winds: Light & Variable Sunday: Mostly Sunny, warm. Highs: low 80's. Winds; NE @ 5-10 MPH. Overnight: Mostly clear. Lows: low/mid 60's. Winds:…