776
FXUS64 KMRX 150823
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
323 AM EST Fri Nov 15 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Today and tonight)
Issued at 316 AM EST Fri Nov 15 2024

Key Messages:

1. A few light showers will linger across the east TN and southwest
VA mountains through late morning and perhaps early afternoon.

2. Most areas keep clouds through the day.

3. Temperatures will be near normal to slightly below normal.

Discussion:

Upper level trough is now to our east and high pressure is to our
west. The ridge axis is centered along the Mississippi River Valley.
Because of this, northwesterly flow will continue across the area
through the day. This results in upslope flow continuing across the
east TN and southwest VA mountains. Therefore, a few light showers
can be expected through late morning and perhaps even into the early
afternoon hours as low-level moisture remains in place. Showers will
be light and less than one tenth of an inch of rainfall is expected.

Guidance shows cloud cover in place through the day for most areas.
This is common this time of year, due to low level moisture getting
trapped on the windward side of the Appalachians. The southern TN
Valley and southwest NC are the only areas likely see some sun by
this afternoon.

Northwest flow and clouds will keep temperatures on the cool side,
with temperatures near to slightly below normal.



&&

.LONG TERM...
(Saturday through Thursday)
Issued at 316 AM EST Fri Nov 15 2024

Key Messages:

1. Dry weather expected this weekend through Monday. Chances for
rain increase Tuesday into Thursday with an approaching front but
details remain uncertain.

2. Above normal temperatures expected Saturday - Tuesday. Much
colder air filters in behind the frontal passage Thursday.

Discussion:

A strong ridge axis builds into the region promoting dry weather and
a warming trend this weekend. While temperatures are not expected to
approach record levels, Sunday through Tuesday will likely observe
temperatures 10-15 degrees above normal for mid-November. By Tuesday
we begin to see a shift in the synoptic pattern as a very dynamic
trough digs into the central CONUS promoting cyclogenesis in the Mid-
west.

Unfortunately there still remains quite a lot of uncertainty with
this weather system as long range guidance just does not want to
come to agreement this far out. The largest disagreements generally
revolve around where exactly the low develops and how it tracks.
Nonetheless, the forecast area will see a return of precipitation
chances Tuesday and through the late second half of the week as a
cold front approaches the area. The initial increase in rain chances
look to be associated with southern stream moisture and an initial
vort max, with a potential brief lull in activity early Wednesday
before a secondary vort max swings through the trough guiding a
surface boundary eastward Wed/Thu.

Depending how far south the the surface low and associated upper-
level features sink, this could also lead to breezy conditions area
wide with the potential for downslope enhancement in the
mountains/foothills with the secondary shortwave energy. By Friday
morning, ensemble probability for rainfall greater than or equal to
0.50" ranges from 40-70%. Probability for wind gusts greater than or
equal to 40mph in the East Tennessee mountains & foothills ranges
from 50-70% Thursday night into Friday morning.

As the frontal passage occurs late week, we can expect much cooler
temperatures associated with H5 height falls. Precipitation chances
will linger into the weekend as a closed upper low swirls over the
Great Lakes region, which could lead to some frozen precipitation in
high elevations with a WNW/NW flow setup, though confidence in
potential accumulation is very low at this time.

&&

.AVIATION...
(06Z TAFS)
Issued at 1243 AM EST Fri Nov 15 2024

A bit of a tricky aviation forecast. Most guidance suggests that
all sites will go MVFR soon. However, northwesterly downsloping
winds will continue off of the Cumberland Plateau through the
night. This could keep CHA and TYS VFR longer than anticipated. So
confidence is low at CHA and TYS overnight. Higher confidence at
TRI where northwesterly downslope winds don`t affect them like
CHA and TYS. VFR conditions anticipated tomorrow afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             62  44  64  43 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  58  43  63  40 /   0   0   0   0
Oak Ridge, TN                       59  43  62  39 /   0   0   0   0
Tri Cities Airport, TN              57  42  60  35 /   0   0   0   0

&&

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

$$

SHORT TERM...
LONG TERM....KRS
AVIATION...