Subj : Area Forecast Discussion For Tri Cities, TN/VA To : All From : Sean Dennis Date : Thu Dec 11 2025 19:00:01 954 FXUS64 KMRX 112337 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 637 PM EST Thu Dec 11 2025 ....New AVIATION... ..KEY MESSAGES... Updated at 632 PM EST Thu Dec 11 2025 - Light snow accumulations across the north tonight into Friday, with impacts most likely across southwest Virginia. - Bitter cold will surge into the area for Sunday into Monday. && ..DISCUSSION... Issued at 1235 PM EST Thu Dec 11 2025 Tonight into early Friday will bring another round of light snow for our far northern areas, especially in SW VA. A weak low pressure system will be diving southeast toward our area out of the Northern Plains, and while it will not have a lot of moisture to work with, a band of isentropic lift and frontogentic forcing north of its associated warm front will bring a band of light precipitation for several hours tonight into early Friday. Thermal profiles suggest this will be mainly snow. The most challenging part of the forecast is exactly where the band will be and for how long, which of course leads to uncertainties about snow amounts. Right now, it appears the main impacts will be along our northern fringe in SW VA. The latest HREF, REFS and NBM probabilities of exceeding an inch across much of SW VA are in the 50-80% range, but generally show low chances of 2 inches of more. This looks reasonable, so will go with amounts of up to 2 inches. Will issue a winter weather advisory for our SW VA counties, with the highest confidence of impacts being across the northern part of the advisory area. Models are in good agreement that a strong cold front will push through our area Saturday night followed by an area of cold high pressure with its origins in Alaska and Western Canada. This system will also have little moisture to work with, and current ensemble data suggests little precipitation. However, a period of snow showers and flurries can be expected Saturday night into Sunday especially north and mountains as the much colder air surges in. It will be quite cold for Sunday into Monday behind the front. Highs Sunday will likely be around or below freezing in valley locations, and Monday morning lows are currently forecast to be in the single digits and teens across our entire area. It currently appears winds will be on the decline once we get later in the night Sunday into Monday which would suppress what could be worse wind chills, but wind chill values in the single digits will be common in the valleys with below zero values for the higher mountains at times Sunday night into Monday morning. High pressure will eventually shift eastward but will keep us dry Monday through at least Tuesday. and Tuesday will be a little warmer. Models are in poor agreement on when the next chance for precipitation will arrive. Current ensemble data supports a gradual warm up continuing for Wednesday and Thursday, with chances for precipitation returning to the forecast by Thursday. && ..AVIATION... (00Z TAFS) Issued at 632 PM EST Thu Dec 11 2025 Light snow still expected overnight tonight into tomorrow morning, with MVFR restrictions most likely KTRI and north. Snow should shrink northward with time through the period after its arrival in East TN, and cannot rule out a brief bout of snow or wintry mix into the central valley to begin the event, though expecting it to remain north of KTYS. Conditions will improve slowly at KTRI back to VFR by 15z, elsewhere gusty southwesterly winds tomorrow afternoon at KCHA and KTYS. && ..PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 33 59 34 58 / 0 10 0 10 Knoxville McGhee Tyson Airport, TN 32 54 33 54 / 20 10 0 0 Oak Ridge, TN 31 54 31 52 / 30 10 0 0 Tri Cities Airport, TN 27 46 30 48 / 50 40 0 0 && ..MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...Winter Weather Advisory from 10 PM this evening to 10 AM EST Friday for Lee-Russell-Scott VA-Washington VA-Wise. && $$ DISCUSSION...99 AVIATION...Wellington --- MBSE BBS v1.1.6 (Linux-x86_64) * Origin: Outpost BBS * Johnson City, TN (618:618/1) .