WDEF-TV News 12 Tennessee River Valley weather forecast Overnight: Early PM Showers/Thunderstorms. Mostly cloudy. Mild. Lows: high 60's to near 70. Winds: Near Calm. Saturday: Sunny hot and humid.  PM Showers/Thunderstorms. Highs: low 90's. Winds: SSW @ 5 MPH. Overnight:…