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

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FXUS64 KMRX 170856

Area Forecast Discussion
National Weather Service Morristown TN
356 AM EST Sun Dec 17 2017

.SHORT TERM...(Today and Tonight)...
Low will be moving towards the area today and will leave a
boundary to our south. North of this boundary will be a region of
isentropic lift causing precipitation over the forecast area.
Precipitation will move in from the south/southwest during the
morning hours. Temperatures in the southern areas should be just
above freezing at this time, so am currently not expecting
widespread frozen precipitation, but a few of the higher
elevations could see a brief wintry mix before temperatures warm
up. Am not expecting much in the way of QPF accumulations today,
especially in NE Tennessee/SW Virginia, with most people seeing
less than a tenth in the north and a quarter inch or so near
Chattanooga. With the increased cloud coverage daytime high
temperatures should remain a few degrees cooler than what we saw

Best area of lift moves off to the east and the moisture along
with it as the day wears on. Precipitation should come to an end
for most with the setting sun, but a few stray showers could
linger into the nighttime hours. With somewhat southerly flow and
continued cloud coverage overnight, temperatures are expected to
remain a bit warmer, around 10 degrees warmer than this morning.

.LONG TERM...(Monday through Saturday)...
Upper ridging strengthens over the region Monday. A weak shortwave
moves through westerly flow south of our area increasing clouds but
no rainfall. Another stronger shortwave trough moves east across
the Southern Mississippi Valley Tuesday with increased southwest
flow and moisture moving into the Southern Appalachians. This will
result in likely rain chances late Tuesday and Tuesday night south
and chance north. The upper level trough axis then to move through
the area Wednesday with the best lift and moisture across southeast
TN and southwest NC. More ridging across the eastern states again
Wednesday night through Thursday with mostly clear skies. Friday and
into the weekend a deepening trough over the Rockies gets kicked
east into the Southern Plains. A surface low over the southern
plains on Thursday moves into the Great Lakes Friday. The trailing
cold front will move across the Tennessee Valley Friday and into the
Southern Appalachians by Saturday morning. A secondary front
saturday will bring more rain and mild temperatures. Temperatures
will stay mild with highs in the 50s to lower 60s all week and lows
mostly mid 30s to mid 40s.


Chattanooga Airport, TN             47  43  60  49 /  60  50  20  30
Knoxville McGhee Tyson Airport, TN  45  40  59  45 /  60  40  10  20
Oak Ridge, TN                       44  39  59  45 /  60  30  10  20
Tri Cities Airport, TN              46  37  57  39 /  40  30  10  20




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