Knoxville started Wednesday, May 20, 2026, in a sticky haze, with pockets of fog and a muggy mid-60s feel. The fog should thin out by midmorning, clearing the way for a hot, humid afternoon with highs near 89°F and a growing chance of showers and thunderstorms late in the day, right as the evening commute ramps up.
Afternoon Storm Risk
Showers and thunderstorms become more likely after about 2 p.m., with around a 50% chance through the late afternoon and evening. Most storms look to stay scattered, but a few late-day cells could pack a punch with small hail and isolated damaging wind gusts. Brief heavy downpours and frequent lightning could slow things down during the drive home. According to the National Weather Service, a marginal severe threat is on the table for parts of northeast Tennessee this evening.
Thursday And The Weekend
The unsettled pattern hangs on into Thursday and the holiday weekend as additional disturbances track through a warm, moist southwest flow. Forecast guidance points to more widespread showers and thunderstorms on Thursday, with some locations picking up around a quarter to a half inch of rain and locally higher totals where storms train over the same spots. Storm chances stick around through Memorial Day. You can dig into the full point forecast and hourly breakdown from the National Weather Service.
What To Bring
For afternoon plans, a rain jacket or poncho is a smart addition to the bag, and be ready to pause outdoor activities if lightning moves in. If you are out on the roads during the evening commute, watch for sudden downpours and reduced visibility, and check local alerts along with the latest National Weather Service forecast before you head out.
