055
FXUS64 KMRX 222300 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
600 PM EST Wed Jan 22 2025

...New AVIATION...

.SHORT TERM...
(This evening through Thursday)
Issued at 318 PM EST Wed Jan 22 2025

Key Message:

1. Dry and cold conditions will continue tonight into tomorrow, but
temperatures will rise at least slightly above freezing for many
places, which hasn`t happened since Sunday.

This Evening/Tonight

Currently this afternoon, a trough is centered to our west with
Arctic high pressure to our northeast. This will continue the dry
and notably cold pattern that has been been in place. Dry air and
subsidence overnight will promote another significant drop in
temperatures. Slight WAA during the day and some light winds
produced by the MSLP gradient will likely limit the drop to be more
in the teens instead of single digits.

Thursday

On Thursday, troughing will gradually approach the area from the
west with westerly to northwesterly flow advecting low-level
moisture. During the day, the result will be an increase in cloud
cover, which will also limit daytime heating in more western areas.
Otherwise, many places will likely rise above freezing for the first
time since this past Sunday.

&&

.LONG TERM...
(Thursday night through next Wednesday)
Issued at 318 PM EST Wed Jan 22 2025

Key Messages:

1. Flurries and light snow showers are possible Thursday night into
Friday, more focused in the higher terrain.

2. A system may move into the all or part of the area Sunday night
into Monday with wintry precipitation possible in the northern half
of the area. Confidence in impacts is still fairly low.

3. Drier and milder conditions arrive by the middle of next week.

Thursday Night through Monday

At the start of the period, troughing will be to our northwest with
westerly to northwesterly flow in the lower levels. Low-level
moisture and CAA are anticipated during this time. This pattern will
continue into at least Friday morning, leading to an increase in
cloud cover and potential for flurries and light snow showers. The
pattern is definitely not ideal for orographic lift based on the
direction and strength of the flow, but some enhancement is still
likely. Light accumulations are possible along some of the highest
peaks, but moisture will likely be too limited to see much in other
places. By Friday evening, a lot of this moisture will have exited
the area to the east with height rises and more zonal flow expected
heading into Saturday. This will help to warm temperatures back
closer to normal with dry weather returning.

By Sunday, the focus will turn more towards the upper-level flow
pattern as two jet streaks in excess of 120 kts come into view. The
southern one will extend from northern Mexico into the southern
Plains with another likely being placed to our northeast. Models do
differ on the strength and placement of these jets, but they will
likely produce a double jet structure somewhere around the region.
The ageostrophic vertical circulation will increase large-scale
ascent and bring a return in precipitation chances. At this time, it
is unclear how far north this area will be and how far south
subfreezing temperatures at or below 850mb will extend. There is a
pretty good consensus for northern portions of the area to be
sufficiently cold enough for wintry precipitation Sunday night into
Monday with less certainty further south. There is also even more
limited confidence on the northward extent of precipitation. For
these reasons, low probability HWO wording will be kept as there is
still at least some potential for wintry precipitation. Otherwise,
any QPF totals would be fairly light for places that just see rain.

Tuesday and Wednesday

Beyond this system, broader height rises are anticipated Tuesday
into Wednesday with expanding high pressure from the south. This
will allow temperatures to rise near to possibly even above normal.
The region would also likely remain dry during this time with some
activity possibly approaching from the southwest later on.

&&

.AVIATION...
(00Z TAFS)
Issued at 600 PM EST Wed Jan 22 2025

VFR conditions and light winds are forecast through this TAF
period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             33  19  41  25 /   0   0   0  10
Knoxville McGhee Tyson Airport, TN  31  16  39  23 /   0   0   0  10
Oak Ridge, TN                       30  17  39  22 /   0   0   0  10
Tri Cities Airport, TN              29  13  35  19 /   0   0   0  10

&&

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

$$

SHORT TERM...BW
LONG TERM....BW
AVIATION...DGS