Knoxville is starting off warm and muggy this morning, with highs near 86°F expected this afternoon. The real story, though, arrives late tonight, when a corridor of thunderstorms is forecast to roll in and linger into Saturday morning, packing the kind of brief, intense downpours that can quickly turn low-lying spots into shallow ponds.
Tonight Into Saturday
Showers and thunderstorms are expected to ramp up after 9 p.m. Friday, with the main window of concern from around midnight to noon Saturday (May 30, 2026). Forecasters are watching for so-called "training" storms - multiple thunderstorm cells tracking over the same neighborhoods - which can wring out very heavy rain in a short time. Some locations could see 1–2 inches of rain in just an hour, raising the risk of localized flash flooding and fast-forming water pooling in flood-prone areas and along small streams, according to the National Weather Service Morristown.
What To Expect
This afternoon should stay partly sunny and warm, with a high near 86°F and a light north breeze. Tonight’s low is expected to dip only to around 66°F, keeping that muggy feel in place.
Showers and thunderstorms are likely tonight, with a 60–70% chance of rain. Most spots can expect around a quarter to a half inch of new rainfall, but any stronger storm could drop much higher totals in a hurry. For hour-by-hour timing and neighborhood-level details, check the National Weather Service.
Impact On Travel And Plans
If you have Friday night outdoor plans, it is a good idea to line up a backup - the heaviest downpours may arrive after dark, and early Saturday events could be soggy and slow to get going.
On the roads, drivers should watch for standing water, sudden loss of visibility and slick spots. Do not drive through flooded streets, and plan for extra travel time Saturday morning. Keeping an eye on local radar and weather alerts will help if you have early travel or work commitments.
Weekend Outlook
Rain chances ease Saturday afternoon as the storms move out, with highs slipping back into the upper 70s near 79°F. Sunday looks like a decent rebound day - partly sunny, just a slight chance of a shower and a high near 80°F. A drier pattern is expected to settle in next week, which should gradually reduce the flood risk, according to the National Weather Service Morristown.
