Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
672 FXUS64 KMRX 111114 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 714 AM EDT Mon Aug 11 2025 ...New AVIATION... .DISCUSSION... Issued at 131 AM EDT Mon Aug 11 2025 Key Messages: 1. Isolated to scattered afternoon showers and thunderstorms are expected to continue much of this week with the greatest coverage along the higher terrain. 2. Increasing moisture by the middle of the week with increasing coverage of showers and thunderstorms in the afternoon. Heavy rain rates possible, with isolated flooding as the primary hazard. Discussion: Currently a few remnant showers are moving through the southern Appalachians tonight with most showers evaporating very quickly once they move off of the mountains. Temperatures will be a few degrees warmer than the past few days, with highs generally in the 80`s for much of the Valley. Isolated showers and thunderstorms are possible in the afternoon, with the greatest coverage along the higher terrain of the Plateau and southern Appalachians. With limited atmospheric forcing, these storms will likely not move far from the mountains. Overnight lows will be in the upper 60s to low 70s, with patchy fog possible in some areas where it has rained. As we move through work week, surface winds will turn more southerly, drawing up additional moisture from the Gulf. This will result in a more humid atmosphere, with dew points likely climbing into the low 70s. This increased moisture will lead to a higher probability of scattered afternoon and evening showers and thunderstorms. PWAT values will also be on the rise indicating much more moisture availability throughout the entire depth of the atmosphere. Storms in the afternoon and evening that grow strong enough to tap into this additional moisture will pose an increased flooding threat with heavier rainfall rates than we`ve seen recently. If any specific location, especially a city, gets multiple rounds of rain or a stationary thunderstorm we could quickly see flash flooding develop as rainfall rates overrun the local drainage systems. The long-range forecast suggests a more active pattern could develop towards the end of the week. Models are currently in disagreement, but there is a small potential for a low-pressure system to develop off the southeastern coast, which could bring increased rain chances to the region. We`ll continue to monitor this potential system. Overall, temperatures are expected to remain above normal, with precipitation also trending above normal for the period. && .AVIATION... (12Z TAFS) Issued at 650 AM EDT Mon Aug 11 2025 MVFR cigs will likely move into CHA for a period this morning, then lift back to VFR before moving in again late in the period. TYS and TRI are expected to remain VFR for the period. There will also be isolated to scattered showers around especially this afternoon, but while a thunderstorm cannot be ruled out the probability of one impacting any given terminal looks too low to include for now. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 88 73 87 72 / 40 20 80 40 Knoxville McGhee Tyson Airport, TN 89 71 87 72 / 30 20 60 50 Oak Ridge, TN 90 71 87 72 / 30 10 60 40 Tri Cities Airport, TN 85 68 86 69 / 50 20 60 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION... AVIATION...