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

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000 FXUS64 KMRX 082022 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 322 PM EST Fri Dec 8 2017 .SHORT TERM (Tonight through Saturday night)...
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Radar has shown a decreasing trend to precip intensity in the last few hours. However we will continue to see at least light snow or flurries overnight until the midlevel frontogenetic forcing associated with the upper jet pushes to our east. Model cross sections indicate that this will persist until late tonight. The northeast mountains and northeast TN Valley and parts of SW VA will likely have the most accumulation due to the longer duration of lift/moisture there, perhaps another 1-2 inches. Central and southern Valley locations and SW NC should have less than an inch of additional snowfall. All current advisories/warnings will be continued through 7 AM Saturday morning. Drier air aloft will build in behind the exiting jet and trough, but a second, more amplified trough axis will be approaching. Clouds will be decreasing through the morning and early afternoon before increasing again from the northwest. The thermal trough will create steep lapse rates in the late afternoon and evening across northern sections, generating scatterd snow showers, and a 30 kt upslope flow will enhance snowfall in the higher terrain. Fast movement of the trough and limited moisture depth should hold accumulations below 2 inches in most of the mountains, with less than an inch in lower elevations of NE TN and SW VA. Wind chills Saturday night will be in the single digits to below zero. A Wind Chill Advisory may need to be considered as we get closer to that period. .LONG TERM (Sunday through Thursday)... Mostly below normal temperatures through this part of the extended as a couple short waves rotate southeast around a nearly stationary upper level low across eastern Canada. From Sunday through Monday flat ridging allows for substantial warming from the upper 30s to lower 40s Sunday to about 10 degrees warmer Monday. A new deepening of the trough over the eastern states by Monday night into Tuesday and a clipper system will bring another round of snow and colder temperatures to the higher elevations and northern parts of the forecast area. These areas may get an inch or two with a dusting at lower elevations. Temperatures will drop 10 degrees for highs Tuesday once again and fall to the teens to lower 20s as skies clear early Wednesday. Wednesday looks very cold with highs upper 20s to upper 30s. Then warming into the 40s Thursday and Friday. A fast moving clipper will brush northeast areas Wednesday night into early Thursday followed by a stronger but warmer system Thursday night and Friday.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 27 42 23 42 / 30 0 0 0 Knoxville McGhee Tyson Airport, TN 27 39 23 39 / 60 10 0 0 Oak Ridge, TN 26 39 23 39 / 20 10 0 0 Tri Cities Airport, TN 29 38 21 36 / 80 20 30 0
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...Winter Storm Warning until 7 AM EST Saturday for Cherokee-Clay. TN...Winter Weather Advisory until 7 AM EST Saturday for Blount Smoky Mountains-Cocke Smoky Mountains-East Polk-Johnson-Northwest Carter-Northwest Greene-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi- Washington TN. VA...Winter Weather Advisory until 7 AM EST Saturday for Washington. && $$ DGS/TD

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