Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
673 FXUS64 KMRX 101730 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 130 PM EDT Sun Aug 10 2025 ...New DISCUSSION, AVIATION... .DISCUSSION... Issued at 109 PM EDT Sun Aug 10 2025 Key Messages: 1. Isolated to scattered convection is expected Monday with the greatest coverage along the higher terrain. 2. Increasing moisture by the middle of the week with increasing chances for showers and thunderstorms, especially during the afternoon hours. Heavy rain rates possible, with isolated flooding as the primary hazard. Discussion: The large upper level ridge over the Eastern US is still in control of our weather, and to our west there is troughing over the Great Plains region. Isolated weak convection is still possible this afternoon mainly over the higher terrain, but most areas will continue to be dry. The light easterly flow in the lower levels will turn more southeasterly on Monday with an uptick in moisture, and while many locations will continue to be dry Monday isolated to scattered showers and storms will affect more areas than today especially during the afternoon. The higher terrain will see the greatest coverage again Monday. By midweek the upper trough over the Plains will be moving east across the Great Lakes Region and into the Northeastern US, with a weak cold front sagging south into the Ohio Valley before stalling out. Our low level flow will turn more southerly, and Gulf moisture will increase over our area. NAEFS data shows PW values increasing to above the 90th percentile for this time of year during much of the Tuesday into Thursday period, and with plenty of available deep moisture we will see scattered to numerous showers and thunderstorms, especially each afternoon, which may be enhanced by weak impulses in the flow that are not able to be confidently timed from this far out. Very heavy rain rates can be expected with the stronger convection, and localized flooding will be possible especially for urban and other flood prone locations. For the latter part of the week into the weekend there is still considerable uncertainty, but it looks likely that broad upper ridging will be in place over the region and the plume of deeper tropical moisture will be shifting off to our southeast. However, with no strong drying expected we will still see mainly scattered showers and storms each day through the weekend. Temperatures will generally run near to a little above normal for the extended period. && .AVIATION... (18Z TAFS) Issued at 109 PM EDT Sun Aug 10 2025 Will start out VFR all sites, and both TYS and TRI are likely to stay VFR for the period. Some MVFR level cigs, and possibly a shower, will move into CHA during the period most likely during the late night or early morning hours. Winds will generally be light. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 71 88 73 87 / 10 40 20 70 Knoxville McGhee Tyson Airport, TN 70 88 71 87 / 10 30 20 50 Oak Ridge, TN 70 89 71 88 / 0 30 10 50 Tri Cities Airport, TN 65 86 67 86 / 10 30 20 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION... AVIATION...