Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
180 FXUS64 KMRX 011135 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 635 AM EST Mon Dec 1 2025 ...New AVIATION... .KEY MESSAGES... Updated at 621 AM EST Mon Dec 1 2025 - Another system will bring gusty mountain winds and widespread rain to the area tonight through Tuesday. Far northeast mountains, including higher elevations of southwest Virginia, may begin as freezing rain Tuesday night. Minor impacts possible. - A changeover to sleet and then snow will occur Tuesday morning into afternoon across some of our northern areas. Limited accumulations at most. Little to no impacts. - Dry Wednesday and Thursday, precipitation chances increasing once again Friday into next weekend. && .DISCUSSION... Issued at 1229 AM EST Mon Dec 1 2025 Today, surface ridging will produce dry conditions until the evening hours. Mostly sunny early, with increasing high and mid- level clouds through the day. For tonight through Tuesday, a northern stream short- wave will dive into the central/southern plains and will phase with a short stream jet energy across the lower Mississippi valley. This will result in strong jet dynamics that will enhancing the fronto- genetic forcing along a boundary over the region. Rain: The HREF ensemble means show between 0.5 and 0.75 inches of rain across northeast TN and southwest VA and 0.75 to 1 inch across the southern TN valley and southwest NC. The REFS means show similar values across our northeastern areas but lower amounts, around 0.5 to 0.75, across the southern areas. Overall, I`d expect a high chance that most areas see at least 0.5 inches and a moderate chance to see 0.75 inches. Some isolated locations could see around 1 to 1.25 inches. Winter: The REFS and HREF both a show that a pocket of freezing rain is likely near the northwest North Carolina/northeast Tennessee state line. The communities of Trade, Mountain City, and Shadey Valley may experience a period of icing from roughly 10 PM tonight through 7 AM Tuesday morning. Possibly effecting eastern sections of Russell and Washington county as well. Freezing rain amounts from a few hundredths of an inch up to a tenth of an inch are expected. Minor impacts are possible, especially across elevated surfaces such as bridges and overpasses. As the system moves east, and colder air builds in from the northwest, deterministic and ensemble probabilities continue to show rain changing to sleet, then snow, Tuesday morning into early afternoon. This is mainly across the northern Plateau, along the TN/KY state line, and portions of southwest VA and the far northeast east Tennessee mountains. Light snow accumulations are possible, generally 1 inch or less. The bulk of the precip will be done by Tuesday afternoon but light snowshowers will likely linger across the east TN mountains Tuesday night due to orographic upslope flow. Little to no impacts expected from the snow. Wind: This system will bring another round of gusty winds, and a probable low-end mountain wave, across the east TN mountains and foothills. Models are showing borderline Wind Advisory criteria. There is a moderate to high chance that a few isolated locations see wind gusts from 40 to 45 mph. The question is, how widespread will the advisory level gusts be. For this reason, will hold off on issuing a Wind Advisory with this forecast package until another round of Hi-Res model data comes in. The most likely timeframe for these higher winds would be from 00Z Tuesday through 12Z Tuesday. For Wednesday and Thursday, upper flow becomes more zonal with surface ridging producing drier and milder conditions. For Friday into next weekend, phasing of an another northern/southern stream systems look plausible with widespread rain. Colder air from wedging into the Carolinas may once again produce a wintry mix across sections of southwest Virginia and northeast Tennessee. && .AVIATION... (12Z TAFS) Issued at 621 AM EST Mon Dec 1 2025 VFR conditions will persist through the first half of the TAF cycle. Increasing low level clouds and rain chances are expected late this evening into the overnight period, generally around 2Z-6Z timeframe. MVFR to IFR cigs will become predominant alongside reduced visibility the activity spreads across the region. A southerly LLJ will also amplify across the region during this time frame. Have included a period of LLWS as latest soundings suggest amplified flow as low as 925mb will promote LLWS. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 51 40 46 27 / 40 100 40 0 Knoxville McGhee Tyson Airport, TN 48 38 45 26 / 20 100 80 0 Oak Ridge, TN 47 37 43 25 / 20 100 60 0 Tri Cities Airport, TN 49 36 43 24 / 0 100 90 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...99 AVIATION...99