Marine Weather and Tide Forecast for Oak Ridge, TN

SHORT TERM
(Today and tonight)
Issued at 247 AM EDT Sat Jun 21 2025

Key Messages:

1. Mostly dry with increasing heat and humidity.

2. Slight chance of a storm over parts of the Southern Appalachians this afternoon and evening.

Discussion:

Satellite imagery this morning, particularly the night fog difference channel, shows some fog trying to form over basically the same parts of the forecast area that were under the Dense Fog Advisory Friday morning. Not expecting this to repeat, though there could be some very isolated patches of dense fog this morning.

A near 1020 mb high sits just east of the region with an almost 590 dam ridge aloft, according to SPC meso. Expect heights to continue to expand into tomorrow. Surface high pressure is expected to strengthen along with it. Albeit weak, flow will start increasing out of the south this afternoon, thus, temperatures and dew points will be a bit higher compared to yesterday. We may just break the latest 90 degree recording since 1997 at Knoxville this afternoon. Normally, we would have officially seen 90 degrees there already.

Overall, a dry day can be expected with the exception of parts of the Southern Appalachians, where there's an isolated chance of a storm this afternoon and evening, primarily from orographic lift and differential heating. A couple hundred J/kg MUCAPE, ample moisture, and nearly no capping, will allow the opportunity for your typical run of the mill afternoon storm. As typically the case with this set-up, activity wanes close to and after sunset.
No official SPC risk outlook is overhead, however they do place much of the forecast area under a general thunderstorm threat.
Heavy rain could be possible with any storm, with PWATs exceeding one inch.

LONG TERM
(Sunday through Friday)
Issued at 247 AM EDT Sat Jun 21 2025

Key Messages:

1. Heat wave expected across much of the area with heat indices from the upper 90s to low 100s.

2. Dry for most areas, for much of the next week. However, some terrain-based convection will be possible at times.

Discussion:

Not much has changed regarding the upcoming heat wave that will affect the area next week. A large ridge of high pressure will be nearly stationary over the Southeast and into the mid-Atlantic seaboard all week. Highs on Sunday are expected to be in the low 90s throughout much of the lower elevations of our forecast area, but those will rise into the mid and upper 90s by the Tue/Wed timeframe.
Heat indices will climb over 100 (possibly up to 105 degrees)
Tuesday through Friday. As is typical, the NBM mean dewpoints appear too high each afternoon. Even with a mix of the NBM and NBM 10th percentile, heat indices will reach 100-105. Record high temperatures (between 96-102 at the 3 climo sites) are not likely to be broken given current guidance. However, it is possible that the current NBM high temps could be underdone by midweek once we have several dry days in a row and soil moisture decreases from recent rainfall. The forecast will nudge up the NBM's highs a bit on Wednesday and Thursday as the drier ground conditions develop.

Expect largely dry conditions given the strong ridge aloft. However, the models are hinting at afternoon convection developing in the NC/TN mountains, so there will be a slight chance PoP mentioned there through the early and middle portions of next week. Rain chances may expand into the TN Valley late in the week when the ridge aloft shows some signs of weakening.

AVIATION
(18Z TAFS)
Issued at 114 PM EDT Sat Jun 21 2025

Light winds and VFR conditions expected for the TAF cycle. For KCHA, VCSH possible this afternoon per latest radar and satellite trends but influence from high pressure and associated subsidence inversion should limit coverage and vertical growth. Persistance forecast expected for tomorrow afternoon.

PRELIMINARY POINT TEMPS/POPS
Chattanooga Airport, TN 71 94 72 95 / 0 10 0 10 Knoxville McGhee Tyson Airport, TN 69 92 72 93 / 0 10 0 10 Oak Ridge, TN 69 93 72 93 / 0 10 0 10 Tri Cities Airport, TN 66 91 67 92 / 0 10 0 10

MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.