Knoxville and Oak Ridge woke up to a soupy mix of fog and low clouds Friday, with temperatures stuck in the mid-60s and visibility trimmed on valley roads. That cool, gray start will not last. By midday, the area flips to hot and humid, with mostly sunny skies and a high near 90°F. Heat index values should land in the mid-90s this afternoon, so if you are outside, keep the water, sunscreen, and shade breaks close by, and allow a little extra time for the morning drive where the haze hangs on.
Afternoon Heat Cranks Up
Afternoon highs around 90°F, paired with light southwest breezes, will make exposed spots feel downright sweltering. It is a good day to scale back heavy yard work or workouts during the hottest part of the afternoon. This is not Knoxville's first fog-to-furnace flip this month, as a similar fog-to-heat setup on June 10 played out almost the same way. Heat will rule today ahead of a shift in the pattern late Saturday.
Evening Into Saturday: Storms Likely
After about 8 p.m. Friday, a chance of showers and thunderstorms moves in, with storm coverage building into Saturday. By Saturday afternoon and evening, showers and storms are likely across much of the region. Some cells could kick out gusty outflow winds around 25 mph, and new rainfall totals of roughly one quarter to one half inch are on the table. Slow-moving or training storms might dump heavier rain over the same spots, which could trigger localized flooding. Forecasters at the National Weather Service Morristown office note that storm coverage should peak sometime between Saturday and Sunday.
Next Week Heat Spike
Once the weekend system slides through, a strong ridge builds in and temperatures climb again. Highs reach near 92°F on Monday, then push into the mid-90s by midweek and into the upper 90s by Thursday. Heat index values may top 100°F in parts of the Tennessee Valley on Wednesday and Thursday. Plan ahead by shifting strenuous work to early morning or late evening and checking on neighbors or family members who are more vulnerable to the heat.
Quick Safety Tips
Hydrate steadily, seek shade or air-conditioned space during the hottest hours, and avoid heavy outdoor exertion between about noon and 6 p.m. If you have outdoor plans on Saturday, keep a backup indoor option ready, keep an eye on radar for incoming thunderstorms, and never drive through flooded roadways. Stay tuned to updated forecasts and local emergency channels if conditions start to change.
