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000
FXUS64 KMRX 151853
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
253 PM EDT Tue Aug 15 2017

.SHORT TERM (Tonight and Wednesday)...
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Scattered showers and a few
thunderstorms will linger over the area this evening. PWs remain
high with values around 2 inches...however..there is little
instability to work with...so main concern will continue to be the
potential for heavy rainfall. Much of the lingering activity
should end overnight with only minimal showers possible. On
Wednesday...an old boundary to our south will lift north across
the area as a warm front. This will act as the main focus for
afternoon convective activity. Instability and upper support
remain low but PWs will stay around the 2 inch mark. This will
again translate to the main concern being the potential of heavy
rains. Also...temperatures will be warmer with highs expected to
reach into the 80s and low 90s.

.LONG TERM (Wednesday night through Tuesday)...A ridge near the
Gulf coast will keep the Southern Appalachian region in a westerly
flow through the end of the work week. This will maintain the
humid air mass with PW values of 1.75 to 2 inches. Little forcing
in the moist air mass will mean mainly diurnally- driven storms on
Thursday. Coverage will generally be scattered to isolated in the
afternoon, and favor the higher terrain. But some weak forcing
ahead of a shortwave trough and surface front may bring an
increase in coverage late Thursday night/Friday morning, mainly
for northern sections. Passage of the front/trough around midday
Friday will be folllowed by drier air through the column in the
afternoon.

The ridge to our south retrogrades over TX for the weekend, putting
our area in a weak west to northwest flow through Tuesday. This
should result in PW values The models do not show any significant
forcing or boundaries near our area during this period, so the
forecast will lean toward a typcial summer pattern of isolated
afternoon convection that favors the higher terrain, and
temperatures near normal.
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&&

.PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN             73  92  75  91 /  30  30  10  30
Knoxville McGhee Tyson Airport, TN  71  89  72  90 /  30  30  20  20
Oak Ridge, TN                       71  89  72  90 /  20  30  20  30
Tri Cities Airport, TN              68  86  68  88 /  20  20  20  30
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&&

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

$$

MJB/DGS