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

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FXUS64 KMRX 202341

National Weather Service Morristown TN
741 PM EDT Sun Oct 20 2019



.SHORT TERM...(Tonight and Monday)...Low clouds are breaking up
across the area and this trend will continue into this evening. Some
low clouds and fog may redevelop tonight especially northeast. Will
include patchy fog for later tonight. A low pressure system will be
moving from the Plains into the western Great Lakes region on Monday
with a cold front moving through western Tennessee Monday afternoon.
Showers will begin to move into western portions of our area late
Monday ahead of this system. Convective energy looks very limited,
but perhaps enough for a few rumbles of thunder over the Plateau
late. Low level winds will be turning more south to southeasterly
later tonight into Monday, which will add a downslope component west
of the mountains and should help to limit clouds and increase
temperatures in the northern and perhaps central valley areas on

.LONG TERM...(Monday night through Sunday)...The period begins in
the midst of the convective system, with categorical POPs
expected Monday night. The advertised temporary LLJ will keep
alive the marginal risk of isolated wind damage, and some locally
gusty winds in general. Still thinking winds aren`t yet deserving
of an advisory, and will allow another look to be made in
following forecast packages. But once the system blows through by
the end of the morning Tuesday, a couple of dry, fall-like days
will follow. Models continue to advertise another chance of rain
late in the week, but they continue to show discrepancies. GFS
remains open with the H5 trough and thus earlier with the event
for Fri and Fri night, but the ECMWF continues to show a closed
low as it did yesterday, and the Canadian concurs, both closing
off the low near the southern Rockies Fri morning, resulting in a
slower eastward progression and a resultant rainy weekend. The
best I could do is go with scattered POPs from Fri to Sunday this
far out. Experience tells me the closed low solution is more
probable, except for the GFS having won some of these tug-of-wars
of late. Time will tell.



Ceilings across the terminals range from VFR/MVFR with heights around
the 3 kft level. IFR to LIFR conditions will return later tonight
with plentiful low level moisture trapped below an inversion.
Best chances for LIFR conditions will be at TYS and TRI with only
MVFR forecast for now at CHA. Low ceilings should mix out quickly
after sunrise with southerly winds increasing throughout the day
ahead an approaching system. Precipitation is forecast just beyond
the end of the TAF cycle.




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