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000
FXUS64 KMRX 171941
AFDMRX

AREA FORECAST DISCUSSION
National Weather Service Morristown TN
341 PM EDT Sat Apr 17 2021

.SHORT TERM...(Tonight and Sunday)...

Upper level flow has transitioned to zonal today as the shortwave
moving through the Ohio Valley continues to wash out. At the
surface, lower pressure was noted east of the southern
Appalachians, while high pressure encompasses much of the plains.
Recent visible satellite imagery continues to depict some clearing
taking place this afternoon as much drier air moves into the area.
The short term period will be quiet, as the region remains
underneath zonal flow tonight and on Sunday. A disturbance begins
to move into the Ohio Valley late Sunday and Sunday night. As a
result, may see an increase in upper lvl clouds Sunday afternoon.
Otherwise, temperatures will remain near to slightly below average
with overnight lows in the upper 30s to mid 40s and highs on
Sunday in the upper 50s to upper 60s.

Diegan

.LONG TERM...(Sunday night through Saturday)...

Warming temperatures to start the week with a cold front at mid week
bringing colder temperatures Wednesday and Thursday. Warming
temperatures again Friday and Saturday with a new system moving in
Saturday. Weak upper troughing across the forecast area to start the
extended period Sunday night with a few showers northern Cumberland
Plateau. Skies will be partly cloudy and lows in the 40s. Monday
improving weather with skies mostly sunny as weak high pressure at
the surface builds in. Mid and upper trough shifts east. Monday
night the weak surface high pressure at the surface and aloft will
shift east. Winds stay light  but shift to a more south southeast
direction. Highs Monday closer to average in the mid 60s o lower 70s
and lows Tuesday lower to mid 40s. Tuesday forecast area is still
mostly dry with continued warming with highs in the upper 60s to mid
70s. Showers develop Tuesday afternoon and evening ahead of frontal
system moving into the Ohio and mid Mississippi Valley ahead of
troughing moving into the mid section of the country. A surface low
is forecast to track from north Texas early Tuesday toward the lower
Ohio Valley later in the day and then deepening as it moves into
Ohio Tuesday night. A few storms are possible late afternoon and
evening. Showers linger overnight ahead of front but not much rain
expected initially. Late Tuesday night and Wednesday a large area of
showers will accompany the front. Much colder airmass moves in
behind the front with precipitation behind the front through the day
Wednesday. Temperatures will be much colder with highs in the 50s
and temperatures possibly falling through the day. Cold air
advection behind the front will drop temperatures down into the 30s
with frost possible western sections if winds lower enough
overnight. Thursday will be another cool day but sunny. Friday lows
again in the 30s and lower 40s but some increase in clouds ahead of
next system. The next system will approach late Friday and Saturday.
More significant rainfall possible late Friday night and Saturday
and continued warmer temperatures.

TD

&&

.AVIATION...
18Z TAF DISCUSSION.

Overall expecting a VFR forecast with some MVFR later in the
period at TYS and TRI. Cannot rule out an occasional isolated
shower this afternoon mainly near TRI but confidence is to low to
include mention. Otherwise, expect a BKN layer around 040-060
through the afternoon and evening with possibilty of gradual
lowering to 025-030 from 09-12Z at TYS and TRI. For CHA, expect
clouds to scatter out overnight. While guidance develops fog
Sunday morning at TYS and TRI, believe clouds may stick around and
inhibit fog formation so will leave this out of the forecast for
now. Winds will remain light and variable.

Diegan


&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             46  70  47  72  48 /   0   0   0   0  10
Knoxville McGhee Tyson Airport, TN  45  67  45  69  45 /   0  10  10   0  10
Oak Ridge, TN                       42  67  46  69  46 /   0  10  10   0   0
Tri Cities Airport, TN              42  63  40  67  42 /  10  10  10  10  10

&&

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

$$