Knoxville, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

334
FXUS64 KMRX 131740
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1240 PM EST Tue Jan 13 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 1233 PM EST Tue Jan 13 2026

- Significant Accumulating snow is likely across the higher elevations,
  with lighter accumulations (dusting to 1/2 inch) for the
  Plateau and valley from late Wednesday afternoon/evening through
  Thursday morning.

- Additional snow showers will be possible this weekend,
  especially over the higher elevations.

&&

.DISCUSSION...
Issued at 1233 PM EST Tue Jan 13 2026

The main concern for the next several days is the potential for
snowfall Wednesday into Thursday. Thus the discussion will largely
focus on the potential of snow during that time-frame.

For Tonight, surface ridging will give way to increasing bounday
layer southwest winds. Sky will be mostly clear in the evening with
increasing clouds toward sunrise. Overall, another good radiational
cooling night and have lowered mins below NBM guidance.

For Wednesday through Thursday, a deepening upper trough across the
eastern United States will produce widespread precipitation. For
Wednesday, a strong 300mb jet of 120-130 knots over the eastern Ohio
valley will place the area under the favored right entrance region.
This jet structure will enhance a frontal boundary moving across the
area during the afternoon and evening. Strong fronto-genetic forcing
is noted around 00Z tightening the thermal gradient along this
boundary.

Initially widespread rain band will spread across the region
associated with the baroclinic band. Vertical temperature profile
quickly cools off due to the forcing with the snow level dropping
quickly. The higher elevations will see snow by 3 to 4 pm, then snow
levels dropping. The dendritic growth zone will be favorable around
00Z then moisture levels become more shallow. REFS shows 60-70
percent probabilities of 4 inch or more across the highest
elevations but most of the higher terrain will see 2 to 4 inches
across the far east Tennessee mountains with 1 to 3 inches across
southwest Virginia mountains.

We have issued a winter weather advisory for these areas from 3 pm
Wednesday through 11 am Thursday.

REFS does show 30 to 50 probabilities of dusting to 1/2 inch
(possibly 1 inch higher ridges) across the Plateau and lower
elevations of southwest Virginia and northeast Tennessee. Plan on
issuing a SPS to message this possibility.

Due to orographic lift and cold air squeezing out left over moisture
have continued chance of shower showers (high elevations) and
flurries for the lower terrain through much of Thursday morning.

For Thursday night and Friday, upper trough has moved east of the
area with another system moving across the Great Lakes and Ohio
valley. The forcing with this system looks to stay north of the
area. Milder temperatures and dry conditions expected. with surface
ridging.

Another deep upper trough digs into the Ohio valley for Friday night
and Saturday. A series of short-waves will move across the region
producing occasional mixture of rain and snow. Ensemble clusters
show varying solutions with this system thus the confidence is low.

&&

.AVIATION...
(18Z TAFS)
Issued at 1233 PM EST Tue Jan 13 2026

Will see VFR conditions for the period.  Winds 2kft off the surface
combined with light surface winds look borderline for LLWS at CHA
and TRI overnight, so will continue to include LLWS at both
locations. However, surface winds will be a bit stronger at TYS so
will not include LLWS at TYS. Very near the end of the period
approaching rain and lower cigs will be be on the doorstep, but will
not include in the TAFS for now as the probability that it arrives
before 18Z still looks low.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             38  52  24  36 /   0  70  30   0
Knoxville McGhee Tyson Airport, TN  40  49  21  32 /   0  90  60  10
Oak Ridge, TN                       36  48  20  32 /  10 100  60  10
Tri Cities Airport, TN              31  48  19  28 /   0  90  70  20

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Winter Weather Advisory from 3 PM Wednesday to 11 AM EST
     Thursday for Blount Smoky Mountains-Cocke Smoky Mountains-
     Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast
     Greene-Southeast Monroe-Unicoi.

VA...Winter Weather Advisory from 3 PM Wednesday to 11 AM EST
     Thursday for Russell-Wise.

&&

$$

DISCUSSION...DH
AVIATION...99