Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
530 FXUS64 KMRX 011715 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1215 PM EST Mon Dec 1 2025 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 1123 AM EST Mon Dec 1 2025 - Gusty mountain winds and widespread rain arrive tonight through Tuesday morning. Far northeast mountains, including higher elevations of southwest Virginia, may begin as light freezing rain tonight. Minimal to no localized impacts expected. Only a cold rain expected for most areas. - A changeover to sleet and then snow will occur Tuesday morning into afternoon across higher elevations of East Tennessee and southwest Virginia. Limited accumulations at most. Little to no impacts. - Dry Wednesday, precipitation chances increasing late Thursday into next weekend with multiple systems. Light precipitation amounts probable. && .DISCUSSION... Issued at 1123 AM EST Mon Dec 1 2025 A strong shortwave trough moves east across the Great Plains this evening and tonight with an upper-level dual-jet structure developing across the region with strong, widespread upper-level diffluence and ascent across the Tennessee Valley and Southern Appalachians. The 850mb southerly LLJ will increase in response to this ascent with a warm nose developing around 5-7k ft. Most of our lower elevations will be above freezing with temperatures in the mid to upper 30s, but localized mountain valleys and higher elevations along the TN/NC state line and into southwest Virginia may see precipitation begin as light sleet or freezing rain tonight. The most likely areas to see a trace to a few hundredths of an inch of ice before the changeover to rain will be in the mountain communities near Laurel Creek, Forge Creek, and Brushy Fork in eastern Johnson County, TN near the TN/NC line. Minimal to no impacts are expected for most areas. As temperatures warm within southerly flow, all areas in our forecast area are expected to be predominantly a cold rain. This system shifts east of the region by mid-morning Tuesday with northerly flow and steady or falling temperatures during the day. Some minor snow accumulation is possible across the higher elevations of the East Tennessee and southwest Virginia mountains, and perhaps some localized spots along the plateau near the TN/KY state line. However, localized accumulation would likely only be a dusting to one-half inch, and no impacts are expected. Drier air arrives by Tuesday night. Patchy black ice could be possible in areas that do not fully dry out, but the dry air and wind should evaporate most moisture on surfaces. High pressure and cooler air brings cool, clear conditions to the region on Wednesday. Chance probabilities of precipitation arrive by late week into the weekend as a quick moving cold front and southerly low pressure system approaches our area. Moisture is limited, but some increased clouds on Thursday afternoon and Friday is expected. At this time, this is most likely an all light rain event for most locations. There is a chance for some wintry mix of rain and/or snow across the higher terrain of the mountains. Details are uncertain and forecast confidence in precipitation probabilities, amounts, and types if fairly low on Friday into Saturday. There is considerable uncertainty with whether these systems will remain weak and separate or phase with a resultant stronger low pressure system. A quick moving northerly stream shortwave may impact the region on Sunday or Monday, but details remain uncertain. At the very least, minimal precipitation accumulation is expected with these likely moisture-starved systems. && .AVIATION... (18Z TAFS) Issued at 1123 AM EST Mon Dec 1 2025 VFR conditions this afternoon with lowering cigs during the evening as moisture increases from south to north. MVFR conditions deteriorate rapidly to IFR overnight across the region. Some LLWS is possible during the overnight hours with light winds near the surface and southerly 40 to 50 kt winds at about 5k ft. Precipitation exits the region by the end of the forecast period with gradually improving MVFR conditions by mid-day Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 42 45 27 50 / 100 40 0 0 Knoxville McGhee Tyson Airport, TN 40 44 26 47 / 100 70 0 0 Oak Ridge, TN 38 43 25 46 / 100 60 0 0 Tri Cities Airport, TN 37 42 24 44 / 100 90 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...JB AVIATION...JB