textproduct: Morristown

KEY MESSAGES

Updated at 624 PM EST Wed Jan 21 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 1231 PM EST Wed Jan 21 2026

I can't stress enough that the forecast for this weekend continues to have quite a bit of uncertainty associated with it. I also cannot stress enough that if the worst case scenario unfolds, the impacts of this storm are going to be quite bad. The trends over the last day or so in model guidance have favored a northward shift of the heavy snow axis, but this has also introduced a northward jog of the mixed precipitation (sleet and freezing rain) transition zone. Couple this with the significant QPF that's forecast, and again this could prove to be a very high impact winter storm. As such, I would advise anyone reading to continue to monitor future forecasts for any changes that might occur.

The overall setup remains largely the same. A closed upper low off the Baja will eject ENE Friday into Saturday, interacting with a shortwave dropping southeast from Montana and a very cold, +1050mb surface high over the upper midwest, to produce widespread precipitation across the southeast Saturday into Sunday. I have fairly high confidence in onset timing, with most all guidance moving precipitation into East Tennessee during the mid morning hours, perhaps by daybreak though in the southern plateau and Tennessee valley areas though. But that's about where the high confidence ends.

As mentioned, the trends have favored a northward shift in the heavy snow axis and mixed ptype zones. This is driven by a more pronounced H85 low tracking from the Ozarks in Arkansas, northeastward into Kentucky and the Ohio valley Saturday into Sunday and the track of the associated surface low moving northeast through Georgia into the Carolinas. The consensus now shows the H85 freezing line lifting north of Knoxville by late Sat afternoon/Sat evening, which is a proxy for where your transition of snow to mixed ptypes will be. What this leaves us with is roughly a 40 percent chance of greater than 6 inches of snow in our northern plateau and up into our western Virginia counties like Lee and Wise, with near zero chances for snowfall in that range as far south as the I-40 corridor. Meanwhile, the odds for notable ice accumulations in the central and southern Tennessee valley have gone up substantially. This seems reasonable based on current guidance, which has trended drier with surface dewpoints (indicating lower wet bulb temperatures and the likelihood that through evaporative cooling processes we can keep surface temperatures at/below freezing through the day Saturday) during the day Saturday despite a warm nose aloft. While there remains considerable uncertainty, which I'll address momentarily, there seems to be enough concern for the potential impacts of this system to go ahead and hoist up a Winter Storm Watch for Saturday and Sunday for the entire forecast area this afternoon.

Let's talk uncertainty. What is the bust potential for this event?

If the northward/warmer trend continues, then we could see snowfall totals in our northern areas continue to dwindle, and may also mean that a sizable portion of our forecast area transitions to an all rain event at some point Saturday evening. Whether the northward trend continues, abates, or whether there's a reversion to a colder, more southern track, remains an unknown. I would say the odds do not favor a southern/colder adjustment based on trends in the upper level pattern over the CONUS, but we just don't know. Additionally, the current forecast reflects over 2" of liquid equivalent QPF Sat and Sun across much of our CWA. We do not have a good handle on how much of this is going to go towards snow, sleet, freezing rain, or possibly rain. If these QPF amounts are correct, and some of the more troubling ice forecasts are near accurate, this storm gets into February 2015 ice storm territory real quick. But if the QPF amounts are right and the warming trend continues, then it's a different story.

Again, I would like to reiterate that there is still a lot of uncertainty with this system. And frankly there's still plenty of time for the forecast to change. Please continue to monitor the forecast for any changes.

Beyond the weekend storm, cold air is going to be in place with lows in the single digits Monday night. Whatever falls is likely to remain in place for a least a day or two. And if the icing scenario plays out, power outages could be a concern with the cold weather in place.

AVIATION

(00Z TAFS) Issued at 624 PM EST Wed Jan 21 2026

Light rain is moving in, and will continue for the next several hours before gradually diminishing later tonight. Expect conditions to dip to MVFR all sites and possibly even IFR, with the highest probability of IFR conditions looking to be at CHA overnight. In addition, winds 2 kft above the surface look marginal for LLWS, and have kept the LLWS in for several hours tonight at both CHA and TRI where the surface winds should be light. Conditions will improve to VFR all sites during the morning hours and then continue to the end of the period.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 40 53 38 46 / 70 20 20 20 Knoxville McGhee Tyson Airport, TN 37 53 34 43 / 50 10 10 10 Oak Ridge, TN 35 52 33 42 / 50 10 10 10 Tri Cities Airport, TN 35 49 29 42 / 40 10 10 10

MRX WATCHES/WARNINGS/ADVISORIES

NC...Winter Storm Watch from late Friday night through Sunday evening for Cherokee-Clay.

TN...Winter Storm Watch from late Friday night through Sunday evening for Anderson-Bledsoe-Blount Smoky Mountains-Bradley- Campbell-Claiborne-Cocke Smoky Mountains-East Polk-Grainger- Hamblen-Hamilton-Hancock-Hawkins-Jefferson-Johnson-Knox- Loudon-Marion-McMinn-Meigs-Morgan-North Sevier-Northwest Blount-Northwest Carter-Northwest Cocke-Northwest Greene- Northwest Monroe-Rhea-Roane-Scott TN-Sequatchie-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi-Union-Washington TN-West Polk.

VA...Winter Storm Watch from late Friday night through Sunday evening for Lee-Russell-Scott VA-Washington VA-Wise.