Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
275 FXUS64 KMRX 271741 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1241 PM EST Thu Nov 27 2025 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 1239 PM EST Thu Nov 27 2025 - Dry and colder through Saturday. - Rain returns by Saturday night, with active/rainy weather continuing into the first part of next week. - Gusty winds possible over the higher elevations and foothills of the E TN mountains Saturday night into early Sunday. && .DISCUSSION... Issued at 1239 PM EST Thu Nov 27 2025 Northwest flow is bringing colder air into the region under a deep upper trough situated over the eastern US, and surface high pressure will keep things dry but cold through Friday. Friday will be quite cold with high temperatures currently forecast to be around 10 to 20 degrees below normal. The upper flow will be turning more zonal and the surface high will slide to our east and northeast by Saturday. Temperatures will moderate a bit although highs Saturday will still be below normal. Another upper trough will be approaching from the west by Saturday night into Sunday, with a surface low tracking northeast out of the Plains into the Great Lakes which drags a cold front through our area Sunday. This system will bring precipitation back into the forecast, and while thermal profiles currently look to support mainly rain, there is a very low chance for some brief wintry precip at the onset in a few spots mainly north. Gusty winds are also likely in some of the higher elevations and foothills of the E TN mountains ahead of the front Saturday night into early Sunday as the low level jet increases with a direction that may be favorable for mountain wave enhancement (it is still uncertain but direction looks close to being a bit too westerly). 850 mb flow looks likely to be around 40 kt which is marginal for gusts to reach wind advisory criteria Saturday night into early Sunday over the usual higher elevation and foothills of the E TN mountains assuming the direction is favorable. For the early part of the week, models are in decent agreement that another upper trough will be moving in from the west with a surface low developing on the frontal boundary to our south and then tracking by most likely to our south and east. The details of course are still uncertain, but right now this system looks likely to bring mainly rain, with the bulk of the precipitation occurring Monday night into Tuesday. Current ensemble data does suggest there is a low chance that wintry precipitation will mix in especially across the north and/or higher terrain, with the probability of 24 hour snowfall exceeding 1 inch topping out around 10% across the north. However, given the potential track to our south and east, the trends on this system will bear watching to see if the chance for wintry precip increases especially on our northern and western fringes. As this system exits, the rain may change to snow showers especially over the higher terrain in the cold advection on the back side, although this looks to be brief. High pressure will be building in along with drier air for Wednesday, with mostly dry weather likely to continue Thursday as well. && .AVIATION... (18Z TAFS) Issued at 1239 PM EST Thu Nov 27 2025 VFR conditions are expected for the period all sites. There is a low chance of brief MVFR cigs at TRI late tonight, but will just include some scattered clouds at 3 kft overnight. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 27 47 27 50 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 24 43 24 49 / 0 0 0 0 Oak Ridge, TN 23 43 23 47 / 0 0 0 0 Tri Cities Airport, TN 22 38 20 48 / 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...99 AVIATION...99