Knoxville, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

829
FXUS64 KMRX 251204 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
704 AM EST Thu Dec 25 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 646 AM EST Thu Dec 25 2025

- Unseasonable warm weather today through the weekend. Near
  record temperatures possible across Chattanooga.

- Low rain chances across southwest Virginia and northeast
  Tennessee for today through Friday night.

- Widespread rain for Sunday night and Monday morning with a
  strong cold front.

- Much colder airmass moves into the Tennessee valley and
  southern Appalachians for late Sunday and especially early next
  week. Wind chills may drop below zero across the higher
  elevations Monday night.

&&

.DISCUSSION...
Issued at 1239 AM EST Thu Dec 25 2025

Currently have a good deal of cloud cover over the region but
with some breaks allowing patchy fog development. Due to the low
dewpoint depressions, do expect patchy fog to continue overnight.

Main weather story for the rest of the week into the first half of
the weekend will be a strong ridge of high pressure and anomaly high
heights over the southern half of the United States. This ridge will
produce unusual warmth for late December with highs around 20
degrees above normal. Near Record highs are possible today,
Friday and Saturday across Chattanooga area.

Christmas Day:

                 Forecast High     Normal High      Record High
Chattanooga:           73               52               75
Knoxville Airport:     69               49               76
Tri-Cities:            64               48               74

A series of jet streaks will move quickly with the fast flow from
the Ohio valley into the central Appalachians for today through
Friday night.  A back door frontal boundary will also approach
southwest Virginia today and be near the area tonight and friday
before lifting north. Due to increasing isentropic lift with each
wave and some fronto-genetic forcing, rain showers chances are
expected for mainly southwest Virginia and northeast Tennessee.
HREF/REFS/LREF and deterministic models show only light QPF amounts
with these systems and generally less than 0.20 inch.

A major pattern change will occur late this weekend and especially
early next week. Ensemble cluster analysis and deterministic
models show a digging upper trough over the eastern third of the
nation. A strong 300mb jet of 160-165kts digs into the Ohio valley
and central Appalachians producing a good deal of jet dynamics as
a strong frontal boundary moves into the area late Sunday night
and Monday morning. Widespread showers is expected especially
early Monday morning.

Much colder airmass quickly moves into the region for Monday and
Tuesday with highs 30+ degrees colder than this week. Highs Monday
will be early in the morning then temperatures falling during the
day.

Wind chills may drop below zero across the higher elevations Monday
night with single digits and teens in the valley. Cold airmass will
settle into the region for Tuesday. A slow moderation will begin
Wednesday.

&&

.AVIATION...
(12Z TAFS)
Issued at 646 AM EST Thu Dec 25 2025

Widespread low clouds should continue across eastern TN through
the period, with a mix of VFR and MVFR expected for KTYS and KTRI.
If clouds dissipate in considerable fashion this afternoon, then
patchy fog could be on the table once again. Winds should remain
fairly low through the period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  57  73  60 /   0  10   0  20
Knoxville McGhee Tyson Airport, TN  69  58  71  59 /  20  10  20  40
Oak Ridge, TN                       68  57  68  59 /  10  10  20  40
Tri Cities Airport, TN              64  55  65  56 /  50  50  40  70

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

DISCUSSION...DH
AVIATION...CD