Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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FXUS64 KMRX 032012

Area Forecast Discussion
National Weather Service Morristown TN
312 PM EST Sat Dec 3 2016

.SHORT TERM (Tonight through Sunday)... Upper-storm system moving
into the region this evening, bringing light isolated to scattered
rain showers into the Southern Valley and Plateau after 00Z. After
midnight, This activity will begin to overspread the entire region,
with the best coverage and intensity occurring after sunrise on
Sunday morning. The heaviest precipitation will occur across the
far Southern Valley and Plateau. However, widespread totals of 0.25
to 1 inch or rainfall is possible through 00z on Monday.
Complicating things overnight will be the height of the melting
level (which will drop to around 3,000 ft). Thus, some very light
snow could occur along the peaks of the East Tennessee and SW
Virginia Mountains. Accumulations will be very light form a dusting
to perhaps 1/2 an inch at most.

The main concern will shift into the day on Sunday during the late
morning through the late evening as a 40-50 kt 850 mb jet will shift
along the high terrain of the North Carolina and East Tennessee
Mountains. These upper-level winds and the strong SE (downslope)
wind component will lead to sustained winds of 15 to 30 mph along
the high terrain of the Smoky Mountains, along with gusts up to 50
mph. These winds could contribute to wildfire growth and spread in
areas that are still burning in the park. This is true, even with
light rain moving into those areas on Sunday as the downslope
component of the winds will act to erode some of the precipitation
shield along the mountains and their surrounding foothills. A wind
advisory has been issued for these areas from 10 AM to 10 PM Sunday.

.LONG TERM (Sunday Night through Saturday)...Scattered rain showers
will continue over the area Sunday evening...with a few showers
lingering over the area through the night as Sunday`s weather system
slowly exits the region.  The area will not see much of a break as
another system moves in from the southwest.  This next system will
bring widespread rain into the area from southwest to northeast for
Monday and Tuesday.  Model consistency becomes quite poor for the
rest of the extended.  Should see a decrease in activity on
Wednesday as the system continues to pull away from the region and
the next system approaches the area. That next system will be a cold
front that will move in around the Thursday time frame.  The ECMWF
is stronger with the frontal passage over the region with deeper
moisture while the GFS has the main lobe of energy to our north with
drier air in place across the MRX CWA. Will go with a
compromise...bringing scattered showers across the area Wednesday
night and Thursday. Much cooler air is expected to push in behind
the front with lows on Thursday night expected to fall into the
teens and 20s and highs Friday only reaching into the 30s. With this
cooler air mass...any lingering showers will transition to light
snow or flurries.  All precip should exits the area for Friday night
and Saturday for cool...dry conditions to begin the weekend.


Chattanooga Airport, TN             43  47  45  56 / 100 100  50  80
Knoxville McGhee Tyson Airport, TN  40  47  42  54 /  90 100  50  70
Oak Ridge, TN                       39  47  42  54 /  90  90  50  60
Tri Cities Airport, TN              35  46  39  53 /  50  80  70  50


NC...Wind Advisory from 10 AM to 10 PM EST Sunday for Cherokee-Clay.

TN...Wind Advisory from 10 AM to 10 PM EST Sunday for Blount Smoky
     Mountains-Cocke Smoky Mountains-East Polk-Johnson-Sevier
     Smoky Mountains-Southeast Carter-Southeast Greene-Southeast



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