textproduct: Morristown

KEY MESSAGES

Updated at 1229 PM EST Thu Dec 18 2025

- Wind Advisory for strong mountain winds; meanwhile widespread showers, and isolated thunder in the south are expected this afternoon into early Friday morning.

- Colder temperatures behind a front on Friday, but rebound quickly over the weekend and remain mild next week with mainly dry conditions.

DISCUSSION

Issued at 1229 PM EST Thu Dec 18 2025

So far, wind obs in the mountains have not been too impressive and under Advisory criteria, with even Cove Mountian only touching 40 mph with the latest ob. The winds are expected to increase as we go through the afternoon, as the NAM shows the 850 mb LLJ around 50 kt in the next few hours, and HREF probs of 40+ kt gusts rising over a larger area across the mountains and foothills. Can't rule out an isolated gust to 55 mph on some mountain peaks, but the probability of reaching this high is low in the HREF. For the TN Valley, we have had a surface inversion this morning that has been preventing winds from reaching the ground at most spots. Looking at the model soundings, that inversion lingers well into the evening until the arrival of a line of showers. The timing of this line appears to be between 03-07Z based on the CAMS. Stronger portions of the line could bring winds aloft down to the surface, with 40 to 50 mph gusts possible. There is some elevated CAPE tonight, enough to warrant a mention of isolated thunderstorms, but not enough for a widespread severe threat. The intensity of the line will be diminishing as it moves from the Cumberland Plateau through the TN Valley.

On the backside of the system early Friday morning, the potential window for snow between the exiting moisture and building cold air appears to close quickly behind the surface front. The upper trough follows closely behind the front, and so dry air aloft builds in rapidly and ends any precip chances by sunrise Friday morning.

Colder temperatures follow the strong cold front on Friday, with highs in the 40s. Highs rebound back to the 50s for Saturday and Sunday. A weak disturbance may bring some light rain Saturday night into Sunday but with low probabilities of measureable rainfall. High temps should be mostly in the 50s for next week. There are some more weak disturbances shown in the models that bring low rain chances next week, mainly Tuesday-Wednesday, but these appear to have little to no impacts, if they happen at all. The general pattern late in the week of a large ridge over TX/LA will favor dry and mild conditions around Christmas.

AVIATION

(18Z TAFS) Issued at 1229 PM EST Thu Dec 18 2025

CHA is expected to have prevailing MVFR cigs through the rest of the afternoon, with downslope winds at TYS and TRI maintaining VFR cigs. A line of showers will spread across the area from west to east from approximately 03-07Z ahead of a cold front. MVFR to IFR conditions are expected with the showers, along with gusty winds. The front will follow shortly after the line of showers, shifting winds to west and lifting vis and cigs.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 36 50 29 58 / 90 0 0 0 Knoxville McGhee Tyson Airport, TN 36 45 27 58 / 100 10 0 0 Oak Ridge, TN 33 45 26 55 / 90 0 0 0 Tri Cities Airport, TN 36 42 25 56 / 90 10 0 0

MRX WATCHES/WARNINGS/ADVISORIES

NC...NONE. TN...Wind Advisory until 4 AM EST Friday for Blount Smoky Mountains- Cocke Smoky Mountains-Johnson-Sevier Smoky Mountains- Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi.

VA...NONE.