textproduct: Morristown

KEY MESSAGES

Updated at 657 PM EST Tue Jan 20 2026

- A jump in temperatures today and Thursday. Light precipitation event tonight into Thursday that will mostly fall as rain, but possibly a mix over higher terrain.

- Confidence in a significant winter storm affecting the southern Appalachian region Saturday into Sunday is increasing. However, it must be stressed that details on where the axis of heaviest precipitation and resulting wintry precip totals remain unclear. This weekend's system should be monitored closely over the next couple of days.

- Cold air behind this weekend's storm will keep temperatures at/below freezing for at least a day or two. This will prolong the effects of any winter weather, with power outages possible as well.

DISCUSSION

Issued at 657 PM EST Tue Jan 20 2026

Early in the day Wednesday should for the most part be quite nice, with valley temperatures reaching the low 50s. High pressure centered over the Appalachians at this time will move east, allowing SWly flow to aid in temperature rises. Thursday will be about the same temperature-wise, but flow reverts back to the west. We will see some precipitation move in later Wednesday, into Thursday coinciding with a cold front separate from the system this weekend. This will primarily be rain for much of us, but as temperatures fall into Friday, a rain/snow mix is possible in the higher terrain with this sort of appetizer system that'll precede the one this coming weekend grabbing everyone's attention. A couple of forecast soundings across SWVA depict potential warm nosing aloft, dry air within the dendritic growth zone, and sfc temperatures near or above freezing. QPF so far is anywhere from a hundredth of an inch to near two tenths.

Friday will be post-frontal and what will begin a rather long period of below normal temperatures through the forecast time- frame, with potentially no sign of relief until early next week. Although, if the ground is completely covered in a mix of wintery precipitation, that could impact just how warm it can get.

Following the Thursday frontal passage, it sets the stage for what could be a long-duration winter event this weekend. The frontal boundary possibly stalls somewhere to our south, meanwhile at the same time, strong Arctic high pressure exceeding 1050 mb dives south from western/central Canada. Once the stationary boundary exits and cold high pressure is centered over the western Great Lakes late Friday, what appears to be multiple low pressure centers form off of the Baja coast and near the Four Corners region underneath a closed low aloft. Separate from that, a boundary forms along the Gulf coast. The aforementioned closed low becomes absorbed into the mean flow and shifts eastward, the upper support needed for possibly multiple days of precipitation, as well as a very strong jet to our north.

The caveats/challenges with this event: for one, we are still far out, therefore, things are still changing with each model run. The 18z NAM ends Saturday morning for example, so not through the entire event. The beginning and end of the event keep shifting. The degree of cold air, strength/location of the Arctic high isn't entirely known which could affect the rain snow line. The axis of heaviest liquid precipitation could be anywhere from GA to across our region, or to our north. Just how much liquid precipitation keeps changing as well. Another localized type feature to watch out for is the inverted trough and just how strong that could get paired with the strength and location of the surface high. As newer model runs have populated in the last couple of hours such as the Canadian and UKMET, consensus is trending towards warmer air aloft shifting further north, possibly to the TN and VA state line, but this will need close monitoring. Needless to say, rain, freezing rain, and snowfall amounts will likely increase or decrease once we get closer and the aforementioned features come more in line. There is still too much uncertainty to say for certain where the changeover could be.

AVIATION

(06Z TAFS) Issued at 1214 AM EST Wed Jan 21 2026

The main aviation impacts will be late in this forecast period. SW winds may become gusty this afternoon at TYS, in the 20-25 kt range. In the evening, LLWS will be mentioned as surface winds drop but winds aloft remain 30-40 kt. Lower cigs may spread in during the evening, but at this time are expected to stay at VFR levels, dropping to MVFR after the end of this TAF period.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 53 38 52 37 / 30 60 30 40 Knoxville McGhee Tyson Airport, TN 53 37 52 33 / 20 50 20 40 Oak Ridge, TN 50 35 50 32 / 30 50 20 30 Tri Cities Airport, TN 50 33 48 29 / 20 40 20 30

MRX WATCHES/WARNINGS/ADVISORIES

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