Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
856 FXUS64 KMRX 041130 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 730 AM EDT Mon Aug 4 2025 ...New AVIATION... .DISCUSSION... Issued at 131 AM EDT Mon Aug 4 2025 Key Messages: 1. Daily rain chances will continue through the week as a trough remains parked over the region. 2. Below normal temperatures expected through mid week, warming back up to near normal by next weekend. Discussion: The CAD wedge has built in strongly across the Southeast and the southern Appalachians, giving very pleasant temperatures and dewpoints this evening for early August. This will remain in place for the next few days, giving below normal temperatures through the middle of the week. Aloft, we will have a weak low pressure at 850 mb, currently over AL, that will drift slowly NE. Today and tonight, the southerly flow of Gulf moisture over the CAD wedge will produce isentropic lift across the region, with further lifting provided by an upper level jet streak. Precip today will be focused mainly in our eastern sections. There will be very little instability, so thunderstorms should be few and far between, less than what the NBM probabilities of thunder would suggest. The upper level forcing and precip axis shifts to the east on Tuesday, which should result in mainly scattered to isolated showers west of the mountains. A mid/upper level trough will continue to sit over the area for the remainder of the week. The flow under this trough will be weak and non-descript, with little in the way of synoptic forcing or advection. But instability will be present, enough to give at least a chance of showers and thunderstorms each afternoon, likely favoring the terrain areas with a diurnal trend. One uncertainty is the track of a tropical low pressure system off the SE coast, and whether that system will move inland late in the week and spread deeper moisture into our area. If so, we could be looking at a very wet pattern next weekend. && .AVIATION... (12Z TAFS) Issued at 727 AM EDT Mon Aug 4 2025 Uncertain about how long MVFR CIGs persist at CHA today, probabilities drop to around 50% between 21z and 06z before increasing again, so lower confidence there. Otherwise VFR conditions should persist at TYS and TRI, outside of a rain shower dragging conditions downward. Stratiform rain this evening across much of western North Carolina into tonight may cross over and impact TYS and TRI. Thunder is not expected. MVFR probabilities increase for all sites after 06z but kept it out of the TAFs for now. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 75 66 79 67 / 50 40 40 30 Knoxville McGhee Tyson Airport, TN 81 66 80 67 / 40 50 50 40 Oak Ridge, TN 81 66 80 67 / 30 40 40 20 Tri Cities Airport, TN 80 63 77 63 / 20 60 70 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...DGS AVIATION...Wellington