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

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000 FXUS64 KMRX 120756 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 256 AM EST Tue Dec 12 2017 .SHORT TERM...
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(Today and Tonight)...Much colder air will push in today on gusty west and northwest winds behind the departing cold front. Enough low level instability and moisture for some snow showers/flurries today, especially in the better orographic lift areas of the mountains. Some of this light precip may be liquid in valley areas early, but expect temperatures to be falling during the day. Will keep the winter weather advisory for the TN mountain zones today. Winds will be quite gusty at times, but looks like wind speeds will generally remain below wind advisory levels. For tonight, any lingering snow showers/flurries will end in the higher terrain and remaining clouds will be clearing out. The combination of winds and low temperatures may bring wind chill values to below zero at times in the higher terrain of the E TN mountains, so will keep the wind chill advisory going in these areas. .LONG TERM...(Wednesday through Monday)...Overall...the extended will be rather active as a series of systems moves through the Southern Appalachian Region. The period will begin on Wednesday with dry conditions and northwest flow aloft becoming zonal as the first system approaches the area. A cool air mass will be in place with weak cool advection continuing across the area. The main part of the system will track to our north Wednesday night into early Thursday morning. Moisture is quite limited over the MRX CWA and associated precip should remain confined to northern locations. With the cool air over the region...expected mainly light snow or flurries with little to no accumulations. Zonal flow aloft will put us briefly between systems for much of the day Thursday into Thursday evening. The next system will move in late Thursday night into Friday. The cool air mass will still be over the area for precip to begin as light snow or flurries Thursday night with light snow transitioning to light rain across most lower elevations during the day Friday. Scattered showers will linger into Friday night across much of the northeastern half with rain switching back to light snow and flurries during the night. A ridge of high pressure builds in for a brief period of dry conditions and moderating temperatures on Saturday. Confidence is low by the end of the period but the trend is for another system to move into the area Sunday into Monday. With warmer air in place...the current temperature profile indicates most valley locations should see rain with some snow possible over higher elevations.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 46 27 47 33 / 10 0 0 10 Knoxville McGhee Tyson Airport, TN 42 24 43 30 / 20 0 0 10 Oak Ridge, TN 43 22 42 30 / 20 0 0 10 Tri Cities Airport, TN 40 17 37 27 / 30 10 0 10
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&& .MRX WATCHES/WARNINGS/ADVISORIES...
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NC...None. TN...Winter Weather Advisory until 7 PM EST this evening for Blount Smoky Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Unicoi. Wind Chill Advisory from 10 PM this evening to 7 AM EST Wednesday for Blount Smoky Mountains-Cocke Smoky Mountains- Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Unicoi. VA...None.
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&& $$ LW/MJB

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