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

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS64 KMRX 091949

Area Forecast Discussion
National Weather Service Morristown TN
249 PM EST Fri Dec 9 2016

.SHORT TERM...(Tonight and Saturday)...An area of surface high
pressure will drift across the area during the period.  It will be
the coldest night of the season so far in valley areas tonight with
winds becoming light under a mainly clear sky.  Tomorrow will
feature plenty of sunshine with just some increase in high clouds
especially late in the day, but it will still be rather cool.  Will
make only minor adjustments to MAV temps.

.LONG TERM...(Saturday Night through Friday)...At the beginning of
this period, we will be under and upper level zonal pattern, with
not significant troughs of ridges over the US.  At the surface, cold
high pressure has settled over the area.  On Sunday, as the surface
high slides to the east, a return flow from the south begins, and
out west a surface low and associated cold front begin to gather
organization in the Plains and Miss Valley. Ahead of the front, an
upper shortwave will be moving toward us Sunday night with chances
of rain increasing.  Also Sunday night, fast 850 mb winds will be
moving into the area, but the pattern is not lined up for the full
mountain wave effect, as the 850 mb winds look to be lined up along
the TN/NC ridgeline, rather than across the ridgeline, and the
surface low drifts farther north...into the Great Lakes, rather than
the favored mid Miss Valley for a classic mountain wave event. Still
looks like an opportunity for a possible wind advisory for the
mountains for late Sunday and into Sunday night. Looks like that
cold front will pass through on Monday, then high pressure builds in
again.  Then the much talked about arctic blast will hit with the
initial frontal passage roughly around Tuesday night or Wednesday,
but that cold push is somewhat up in the air as models still show
great differences in timing, but there is good agreement that
Thursday and Friday will be cold.  Not crazy about the post-frontal
POPs that the blend has come up with; have cut the POPs generally
about 10% overall in the Wed-Fri timeframe, thinking that the timing
of these systems--some member having a slower solution with
lingering POPs in the warmer air, while other solutions are colder
and drier, with the averaging getting some more abundant moisture
than will really be in the cold air. Anyway, at this point, any
wintry precip in the latter half of the week should be light.


Chattanooga Airport, TN             22  45  28  51 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  19  41  25  50 /   0   0   0  10
Oak Ridge, TN                       19  42  25  49 /   0   0   0  10
Tri Cities Airport, TN              16  39  21  46 /   0   0   0   0




LW/GM is the U.S. government's official web portal to all federal, state and local government web resources and services.