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

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FXUS64 KMRX 220657
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
257 AM EDT Fri Sep 22 2017

.SHORT TERM (Today through tonight)...-- Changed Discussion --At the beginning of this
period, we are under a rare northeast flow aloft, between high
pressure to our west and northwest over the Miss Valley and a trough
to our east associated with tropical system Jose. Short-range
models show some deep convection developing today over the high
terrain near the TN/NC state line during the afternoon heating, but
with the flow from the northeast, much of this convection/precip
will stay over this high terrain, riding down the ridgeline. The
NE flow will proceed to push this convection across the Hiwassee
and Ocoee Valleys in our extreme southeastern counties this
afternoon. With the convection being driven by the diurnal
heating, it should fade quickly this evening. Drainage winds again
tonight should favor a repeat of localized valley/lake fog late
tonight. Will stick close to guidance temps.

.Long Term (Saturday through Thursday)...Once again, a quiet
and uneventful long-term period in store but change is on the
horizon. High pressure centered over the Great Lakes region will
continue to dominate our weather through the extended, allowing for
above normal temperatures and little to no rain chances.

Have slight chance POPs to start the period Saturday afternoon
across portions of southern plateau, SWNC, and our eastern
mountains. Then no POPs through the rest of the week until Thursday.
Highs Saturday through Wednesday will generally be in the mid to
upper 80s, which is around 5 to 8 degrees above normal. Lows will be
in the low to mid 60s, which is around 5 degrees above normal. High
pressure breaks down on Thursday in response to an upper level
trough moving across the Great Lakes. This trough has an associated
frontal boundary that will make it`s way through our area but beyond
this long-term forecast. The front is across the Ohio River Valley
on Thursday. By Thursday afternoon have slight chance POPs in for
all areas as front draws closer. Highs on Thursday will be a few
degrees cooler as flow becomes more zonal. Highs will be in the
upper 70s to lower 80s.-- End Changed Discussion --

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --Chattanooga Airport, TN 88 66 87 65 / 10 10 10 0
Knoxville McGhee Tyson Airport, TN 87 65 87 64 / 10 10 0 0
Oak Ridge, TN 88 65 87 64 / 10 10 10 0
Tri Cities Airport, TN 85 60 86 58 / 10 0 0 0-- End Changed Discussion --

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

GM/SR

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