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

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FXUS64 KMRX 210807
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
307 AM EST Tue Nov 21 2017

.SHORT TERM...(Today through Thursday night)...
A low level ridge off the NC/SC coast will produce a southerly
flow that will advect higher theta-e air across GA and into the
Appalachians today, while a cold front will advance toward our
area from the NW. Satellite and obs show low clouds spreading N
across GA, nearly to our SW NC counties. Model moisture profiles
show that it is confined below 850 mb with very dry air above, but
with some isentropic lift from a 30-40 kt wind at 290-295 K,
drizzle or light rain will be a possibility today, mainly in the
mountains. NAM QPF amounts over a tenth in SW NC seem rather high
given the lack of moisture depth, and just a few hundredths of an
inch seems more realistic. The cold front sweeps through our area
late tonight, which will be a dry fropa for most of the area with
the low level moisture/isentropic lift having pushed east of the
mountains by that time.

Surface high pressure will build over the region for the rest of
the short term period, with a dry W to NW flow aloft. A shortwave
trough that crosses the area on Thursday will have too little
moisture with it to affect the sensible weather, other than
perhaps an increase in high/mid clouds.

.LONG TERM...(Friday through Monday)...
Some rather decent weather is in store for the last few days of
November even though another upper trough and cold front will be
building across the region over the weekend. The front moves
through on Saturday but there is no low level inflow of moist air
off the Gulf due to the presence of a large surface ridge over the
Southeast states. Another amplified ridge pattern fills in behind
the early weekend system for a gradual return to sunshine. The
sunshine won`t be too effective in warming the lower atmosphere
Sunday and Monday with highs rising only to the 40s both days.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             56  41  55  35 /  10   0   0   0
Knoxville McGhee Tyson Airport, TN  55  41  53  35 /  10  10   0   0
Oak Ridge, TN                       57  40  53  34 /   0   0   0   0
Tri Cities Airport, TN              59  40  53  28 /  10  10   0   0

&&

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

$$
24/99




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