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

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000 FXUS64 KMRX 172006 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 306 PM EST Wed Jan 17 2018 .SHORT TERM...(Tonight and Thursday)... Current water vapor imagery and RAP upper air analysis indicates a closed low across the Southern Appalachians. At the surface, the cold front is now along the Atlantic Seaboard with a surface high pressure back to the west across the Lower Mississippi River Valley. Cold air continues to advect into the Southern Appalachians behind the departing cold front. Some flurries have lingered across the area today but it appears that any accumulating snowfall has come to an end. The main story tonight will be the bitterly cold airmass that will be in place. Cloud cover will decrease tonight as drier air continues to advect into the forecast area. Winds will weaken as the surface high pressure approaches the region. Add in the recent snow cover and this recipe will make for the coldest night of the season. Winds will remain in the 5-10 mph range across the higher elevations and issued a wind chill advisory for the E TN mountains, SW NC, and Washington and Russell counties in SW VA. For these locations expect wind chill values in the 0 to minus 10 degree range overnight. Dropped overnight lows by a couple of degrees with most locations in the single digits. There has been some melting today with the sunshine and any remaining moisture on the roads will refreeze and turn into black ice. Please use extra caution while traveling tonight. The pattern will begin to shift some moving into Thursday with a shortwave ridge moving over the area. Upper level height rises and ample supply of insolation will lead to warmer temperatures. Forecast highs will generally be in the 30s. .LONG TERM...(Thursday night through Tuesday)... High pressure and westerly flow will be present through the the rest of the work week and into the weekend. Dry weather and mostly clear skies will be present...with a slight warming trend to the temperatures each day. By Sunday...the mid level flow will transition to out of the southwest...bringing warm air and more moisture to the area. A low pressure system developing over the MS Valley will move to the east through Sunday night and Monday...bringing a frontal boundary will the system. Instability looks low...and PW values are high for this time of would expect scattered to widespread showers across the area. Upper level forcing is present through the day Monday...and a few areas could hear a rumble of thunder or two...but for now...have left mention of thunderstorms out of the forecast until future model runs show more instability and lift. The front is expected to move through by Monday night...and a mid level jet will move through the area...bringing gusty winds of around 30 to 40 mph through Monday afternoon and early evening. By Tuesday morning...northwest flow sets up over the area...with drier and cooler air settling in for the day Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 10 38 20 48 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 7 35 17 46 / 0 0 0 0 Oak Ridge, TN 6 35 17 47 / 0 0 0 0 Tri Cities Airport, TN 6 34 15 47 / 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...Wind Chill Advisory from 7 PM this evening to 9 AM EST Thursday for Cherokee-Clay. TN...Wind Chill Advisory from 7 PM this evening to 9 AM EST Thursday for Blount Smoky Mountains-Cocke Smoky Mountains-East Polk- Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi. VA...Wind Chill Advisory from 7 PM this evening to 9 AM EST Thursday for Russell-Washington. && $$ MA/JW is the U.S. government's official web portal to all federal, state and local government web resources and services.