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659
FXUS64 KMRX 051943
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
243 PM EST Thu Dec 5 2019

.SHORT TERM...(Tonight and Friday)...
This afternoon it was sunny with temperatures in the 50s and lower
60s. Winds were light and variable with a couple of locations
reporting some wind gusts between 8 and 12 mph. Satellite imagery
was showing increasing clouds moving into Middle Tennessee.

The next system to affect the region is currently located over the
Four Corners. This shortwave will translate quickly across the
southern Plains tonight. Overnight winds will gradually shift to the
south as the area of high pressure moves off the Carolina coast.
Clouds will be on the increase mainly after midnight. Due to the
southerly winds and increased cloud cover, overnight lows will be
mild - in the 30s and 40s.

By Friday morning the shortwave and associated front will be moving
across Tennessee. The forecast soundings show a dry lower levels
with near saturation from about 8-10kft. Therefore, rainfall amounts
during the late morning through the remainder of the afternoon will
be rather light (less than one tenth). The exception would be areas
south of I-40 such as McMinn, Marion, Hamilton and Bradley Counties
where amounts could be closer to one quarter inch.

.LONG TERM...(Friday night through Thursday)...
Model agreement is a bit better than 24 hours ago, but still some
significant differences in the details. Forecast confidence
continues to be slightly above average for this time of year.

A few patches of light rain may linger into the first part of Friday
night, but while the deeper moisture clears out it appears a lack of
low level drying may allow low clouds to linger into Saturday,
especially south, before breaking up.  High pressure to our north
will slide east Saturday night and Sunday, and flow will turn more
southerly allowing moisture to begin to increase.  Clouds will be
increasing from southwest to northeast later Saturday night and
Sunday, but precip should hold off allowing Sunday to be dry.

A mid/upper level trough will dig into the plains and then shift
east into the Eastern US Sunday night through Tuesday night. The
surface low will track by to our west and into the Great Lakes and
then Eastern Canada, with a cold front pushing through our area most
likely Monday night/early Tuesday.   The best chances for rain will
be Monday afternoon through Tuesday morning. This will be a warm
system on the front end, so the bulk of the precipitation will be
liquid. Colder air moving in behind this system may bring some snow
showers on the back end Tue night, then Wednesday and Thursday look
dry. One thing to watch will be the strength and wind direction in
the low level jet Sunday night through Monday night, as mountain
wave enhancement of the winds may occur.  There may also be some
heavy rainfall especially Monday night/early Tuesday ahead of the
front. However, models have not been consistent and are not in good
agreement at this point with any of these details, and confidence is
still too low to include these in the HWO at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             42  53  43  56 /  10  60  40  10
Knoxville McGhee Tyson Airport, TN  38  50  39  56 /  10  50  20  10
Oak Ridge, TN                       38  49  39  56 /  10  60  20  10
Tri Cities Airport, TN              34  48  36  53 /  10  50  20  10

&&

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

$$

AC/LW