textproduct: Morristown

KEY MESSAGES

Updated at 604 PM EST Wed Dec 17 2025

- Strong mountain winds, widespread showers, and isolated thunder in the south are expected Thursday 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 1233 PM EST Wed Dec 17 2025

Over the next 48 hours, a strong, deep upper trough and associated surface cold front will affect the area. Although the center of the surface low will remain well north, in the northern portions of the Great Lakes, the strong amplification of the upper trough and upper jet positioning will result in a pretty dynamic system in the OH/TN Valleys. Today and tonight, the low level air mass will be quite dry, but low levels will gradually moisten through Thursday with isentropic lift and warm advection. The pressure gradient along the Appalachians starts to tighten Thursday morning, and some of the higher peaks, such as Cove Mountain, may start to see gusts near 40 mph as early as 12Z. Gusts in the 40-50 mph range will become more common in the mid to late afternoon for areas in the mountains and foothills that tend to be affected by mountain wave winds. A few isolated spots could reach High Wind criteria Thursday night, but confidence on that is still low. Will hold off on issuing any Wind Advisories for now since we have over 24 hours before its expected start time. If a low level inversion Thursday morning erodes in the afternoon, then Valley locations will likely see some strong winds as well.

Rain with this system arrives Thursday afternoon as isentropically- driven scattered showers in southern sections, with increasing coverage and a northward spread through the evening as QG forcing builds in earnest. A few thunderstorms are possible across the southern tier between 00-06Z, where some forecast soundings indicate weak elevated instability. Despite limited instability, the strong low- level jet could allow heavier showers to mix down gusts of 3040 mph, particularly as the main axis forcing moves through. However, the risk of damaging winds remains low. On the backside of the system early Friday morning, light snow may occur if cold air advection and northwest flow align with lingering moisture. Any accumulations would likely be very light given the short duration of overlap between the exiting moisture and the building cold air.

Colder temperatures follow the strong cold front on Friday, with highs in the 40s. Highs rebound back to the 50s for Saturday and Sunday, and should be mostly in the 50s for next week. There are some 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.

AVIATION

(00Z TAFS) Issued at 604 PM EST Wed Dec 17 2025

LLWS in at all sites by tomorrow morning. VFR at CHA and TYS from now until late tomorrow morning/afternoon when ceilings lower due to the arrival of rain showers. TRI should remain VFR through the period due to downsloping winds off the east TN mountains.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 40 60 36 50 / 0 90 100 0 Knoxville McGhee Tyson Airport, TN 35 62 36 46 / 0 90 100 0 Oak Ridge, TN 34 59 33 45 / 0 80 100 0 Tri Cities Airport, TN 34 60 35 42 / 0 80 100 0

MRX WATCHES/WARNINGS/ADVISORIES

NC...NONE. TN...NONE. VA...NONE.