123
FXUS64 KMRX 092327
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
627 PM EST Sun Nov 9 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 608 PM EST Sun Nov 9 2025

- Much colder air will usher into the region tonight through
  Tuesday. Temperatures will be as much as 20 degrees below normal
  by Monday and single digit windchills are expected across the
  higher terrain Sunday night through Monday Night.

- Behind the front, snow will be a concern for many areas through
  early Tuesday morning. The Smokies are looking at a significant
  snowfall event, possibly exceeding 12" at higher peaks such as
  Mount LeConte, while the remainder of the east TN mountains and
  higher terrain of our VA counties see lighter amounts generally
  in the 1 to 4 inch range.

- Generally speaking, valley accumulations should wind up around
  half an inch or less, and mostly occur Monday evening and
  Monday night. There could be some places that get an inch or so,
  but confidence in exactly where those accumulations occur is
  very low.

- Dry and more seasonal temperatures will return to the area mid
  to late week.

&&

.DISCUSSION...
Issued at 205 PM EST Sun Nov 9 2025

A cold front continues to progress east of the area this afternoon
as winds have become breezy and from WNW behind the departing
surface boundary. Satellite imagery helps distinguish shortwave
energy aiding in the amplification of upper-level troughing over
the Ozarks and Mississippi River Valley.

As we head into the evening, H85 winds will veer more northwesterly
and amplify to around 25-30kts as the highly anomalous troughing
makes way atop the Ohio and Tennessee Valley. Latest NAM cross-
sections suggest H85 temperatures approaching 0C around the 21Z
timeframe. The cooling temperatures and nwly flow 700mb and lower
will promote the start of a northwest flow snowfall event. Tonight
into early Monday moisture will be more on the shallow side, with
saturation not occurring much higher in the atmosphere than the
-10 to -12C heights. Light accumulating snowfall will be limited
 to higher elevations of southwest Virginia and the Tennessee
 mountains. However, tallest peaks generally 5000ft plus could see
 some moderate to heavy snowfall where orographic lift helps
 overcome the more shallow moisture. Some snow flurries or weaker
 snow showers cannot be ruled out across valley locations during
 this time, but the lack of DGZ moisture and lag of cooling
 grounds will hinder valley floor accumulations.

A secondary impulse is expected to round the base of the trough
Monday afternoon into Monday evening. Increased vorticity and
reinforcement of the northwesterly flow will give us an additional
shot of wintry precipitation. In fact, the nwly flow will expand
through a majority the vertical column, increasing lapse rates while
temperatures will continue to cool and saturation expands to the low
to mid -20C. This enhanced flow will be a little shorter in duration
than the initial push, however, the moisture and strength of the
winds are more favorable for NWFS. Overall, HREF probabilities of 4"
or greater are 50-90% across the E TN mountains, with probabilities
of 10" greater at 50% for the very highest peaks in the Smoky
Mountains. These values being for an event total tonight through
Monday night.

Overall, the current forecast was in pretty good shape. Some minor
tweaks to snowfall values with slightly higher totals at those
tallest peaks. Increased the wording of 10-12in to 10-15in in the
Winter Storm Warnings while also expanding it include Greene
mountain Zone and Unicoi county. Advisory products remain
largely untouched excluding the addition of Lee county VA, but
will continue to evaluate the potential accumulations with the 2nd
impulse. Future advisories are not totally out of the question
for the northern plateau. Valley accumulations should generally be
less than 1", and would be most likely to occur during the 2nd
impulse as well. However, a few CAMs do show very thin bands of an
inch or so due to the enhanced moisture depth and lapse rates.
Will keep monitoring this, but continue to think due to the low
confidence in where exactly a band may setup, we are okay without
an advisory. Lastly, temperatures will be very cold during this
period. The majority of the area will see lows into the 20s both
tonight and Monday night. This will pose a period of single digit
windchill for the higher terrain as well.

Dry weather with a gradual return to near seasonal temperatures is
expected Tuesday into late week following the ejection of the trough
to the north and east. By the end of 7 day period, PoP chances make
a return ahead of an approaching front associated with an occluding
surface low over the mid-west.

&&

.AVIATION...
(00Z TAFS)
Issued at 608 PM EST Sun Nov 9 2025

A few showers and then snow showers/flurries will be around,
mainly tonight and again late in the period and especially at
TYS/TRI. CHA may briefly dip to MVFR early in the period with a
shower, but will likely see mainly VFR conditions and little
precipitation. TYS and especially TRI are more likely to see
conditions lower to MVFR tonight, and then again late in the
period at least at TRI. Westerly winds will be gusty at times,
especially during the day Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             28  39  25  49 /   0  10  10   0
Knoxville McGhee Tyson Airport, TN  28  34  24  45 /  30  20  20   0
Oak Ridge, TN                       27  34  23  44 /  20  20  10   0
Tri Cities Airport, TN              28  33  21  40 /  50  30  50   0

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Winter Weather Advisory until 7 AM EST Tuesday for Johnson-
     Southeast Carter-Southeast Monroe.

     Winter Storm Warning until 7 AM EST Tuesday for Blount Smoky
     Mountains-Cocke Smoky Mountains-Sevier Smoky Mountains-
     Southeast Greene-Unicoi.

VA...Winter Weather Advisory until 7 AM EST Tuesday for Lee-Russell-
     Washington VA-Wise.

&&

$$

DISCUSSION...KRS
AVIATION...99