Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
137 FXUS64 KMRX 230006 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 806 PM EDT Fri Aug 22 2025 ...New AVIATION... .DISCUSSION... Issued at 105 PM EDT Fri Aug 22 2025 Key Messages: 1. Diurnal convection today and through the weekend. Greatest coverage across southeast Tennessee, southwest North Carolina, and the higher elevations. 2. Drier and cooler behind a cold front next week as high pressure arrives. Discussion: Diurnal convection continues each afternoon with a weak shortwave trough and low-level convergence within southeasterly flow. A majority of convection is forecast to be south of Interstate 40 where instability is higher and across higher elevation regions. With weak flow and PW values between 1.8 to 2.0 inches, heavy rain rates and slow moving convection could result in some localized flash flooding concerns this afternoon and tomorrow afternoon. A cold front moves across the region on Sunday. Showers and a few thunderstorms are expected, but low-level winds will shift to the W/WNW ahead of the front bringing in some drier air. For this reason, widespread heavy convection is not a guarantee. There`s a high chance >70% chance that most areas receive at least 0.01 inch of precipitation this weekend, but the probabilities are much lower for values exceeding 0.25". Behind the cold front, colder and drier air arrives next week. High pressure will keep us dry and temperatures around 10 degrees below normal. A few weak disturbances may result in some increased mid-level or high clouds mid-week, but with the low-level dry air, do not expected precipitation. && .AVIATION... (00Z TAFS) Issued at 751 PM EDT Fri Aug 22 2025 Thunderstorms around parts of the forecast area tonight, nearest to TRI. CAMs suggest activity should wane with time the next couple of hours. MVFR CIG and perhaps fog, possible at CHA and TRI overnight and into Saturday morning. Conditions should improve to VFR near daybreak, before the chance for showers and storms returns in the afternoon and evening ahead of a FROPA late Sunday. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 71 86 70 86 / 20 70 50 50 Knoxville McGhee Tyson Airport, TN 70 86 70 83 / 20 70 60 50 Oak Ridge, TN 70 86 68 84 / 20 70 60 50 Tri Cities Airport, TN 66 84 66 80 / 10 70 60 70 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION... AVIATION...KS