Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
227 FXUS64 KMRX 181723 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1223 PM EST Tue Nov 18 2025 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 1200 PM EST Tue Nov 18 2025 - Low relative humidity this afternoon/evening with increasing winds. This will lead to enhanced fire danger. - Warmer, above normal temperatures continue Tuesday through Friday, with warmest days on Wednesday and Thursday. - Light rainfall tonight with potential for a few thunderstorms. Rain chances will begin to increase again Thursday afternoon, with more widespread rain coverage Friday into Saturday. && .DISCUSSION... Issued at 1200 PM EST Tue Nov 18 2025 Winds will begin to increase today and the flow will turn more southwesterly ahead of an approaching upper level shortwave. Limited moisture return and warm temperatures will result in low relative humidity values across the region this afternoon and evening. The low relative humidity and increasing winds, especially across the Cumberland Plateau and higher elevations of southwest Virginia, will bring another day of Enhanced Fire Danger across the entire area through the evening hours. Quick moving shortwave moves across the Great Lakes and Ohio Valley tonight with a surface front moving southeastward across the forecast area overnight. A majority of the synoptic ascent is north of our forecast area, so precipitation across our region is forecast to be more scattered/less widespread with primary forcing directly along the front. With limited low-level moisture ahead of the front, the surface airmass will remain cool and stable. Any limited instability is forecast to remain elevated. While there is a low chance for an elevated thunderstorm, the majority of precipitation tonight into Wednesday morning is expected to be scattered rain showers. With a 850mb LLJ around 50 kt this evening across Kentucky through southwest Virginia, some higher elevations will have wind gusts up to around 40 mph. We dry out Wednesday afternoon with shortwave ridging across the region. As troughing amplifies across the Southern Great Plains and Southern Rockies, we will be within SW flow aloft with isentropic lift increasing across the region on Thursday. This will increase clouds and chances for light stratiform rain showers late on Thursday. Temperatures remain warm on Wednesday and Thursday with temperatures near record values, especially south of Knoxville. Daily Record High Maximum Temperatures Date Chattanooga Knoxville Tri-Cities Oak Ridge 11-18 79(2016) 80(1985) 79(1958) 77(2016) 11-19 77(1985) 83(1985) 78(1985) 80(1985) 11-20 78(1942) 80(1906) 75(1988) 74(1992) As the primary shortwave vort max moves across the Tennessee Valley late Friday and Friday night, chances for rain, and a few thunderstorms, will increase across the region. Behind the departing shortwave and surface front, we begin to dry out by late Saturday into Sunday. Drier weather is forecast to continue into early next week ahead of a stronger low pressure system that is expected to develop across the Southern Great Plains and move our direction by the middle of next week. && .AVIATION... (18Z TAFS) Issued at 1200 PM EST Tue Nov 18 2025 VFR through this afternoon. MVFR conditions due to low cigs at all sites tonight as scattered rain showers move through the area. MVFR then persists through the end of the period, except CHA where a return to VFR is forecast late in the period. At TYS, gusty southerly winds expected through late tonight. At TRI, LLWS is expected tonight. Surface winds at TYS should be high enough that LLWS criteria isn`t met but will be borderline. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 59 76 55 76 / 70 10 0 10 Knoxville McGhee Tyson Airport, TN 56 71 53 71 / 80 10 10 10 Oak Ridge, TN 54 70 52 69 / 90 10 10 10 Tri Cities Airport, TN 49 63 51 66 / 80 10 10 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...JB AVIATION...99