Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
037 FXUS64 KMRX 160539 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 139 AM EDT Thu Oct 16 2025 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 138 AM EDT Thu Oct 16 2025 - Dry and mild conditions will continue today with cooler overnight lows in northeasters areas. Patchy frost is possible. - A system will affect the region this weekend, bringing potential of strong winds in the mountains Saturday night. Showers and storms are likely by Sunday, and the severe threat is dependent on how slow the front moves in during the afternoon. - Drier and cooler conditions return by Monday, followed by a warming trend and possible showers and storms mid-week. && .DISCUSSION... Issued at 138 AM EDT Thu Oct 16 2025 Currently early this morning, broad ridging is centered to our west with surface high pressure over the upper Great Lakes, continuing northeasterly flow and dry and mild conditions. Heading into tonight, ridging will gradually shift eastward with surface high pressure settling just northeast of our area. The combination of increasing subsidence and weaker MSLP gradient/winds will allow for temperatures to drop more than recent nights in the northeast. Some places could reach the upper 30s with patchy fog definitely possible for some. On Friday, the flow aloft will become more zonal with surface high pressure weakening as it progresses east of our area. This will continue the warm and dry conditions with a more southerly shift in winds. On Saturday, the pattern to our northwest will be the main focus as troughing deepens and becomes negatively tilted with cyclogenesis taking place across the Great Plains. Models still differ some on timing and exact evolution, but the consensus is for a surface low below 1,000mb to develop and progress to the Great Lakes by the evening. Strong upper divergence due to upper divergence to the north will strengthen 850mb flow to over 50 kts ahead of the cold front. During the day on Saturday, the result in our area will be unseasonably warm temperatures and increasing southerly winds. Depending on the exact orientation of the 850mb jet and MSLP gradient, a mountain wave event could transpire overnight. However, there are still questions about these details. The next question will be about the timing of the cold front on Sunday. The latest GFS solution is actually slower than the NAM. A slower timing could allow for better destabilization in our area ahead of convection in the afternoon. Based on the overall pattern, strong directional and speed shear would almost certainly be in place with increasing instability supporting a notable severe risk. This risk would be greatest in southern portions of the area where probabilities for sufficient instability are highest. Essentially, the slower the timing in the front, the higher the severe risk will be in our area. Troughing and the associated cold front are expected to be east of the area by Sunday evening, leading to cooler and drier conditions. An area of high pressure will keep the region dry on Monday. By the end of the period, there are indications of another trough/system moving into the region. Some sources suggest this setup to also be potentially dynamic and conducive for storms in the eastern U.S. with a return of rain chances in our area at a minimum. && .AVIATION... (06Z TAFS) Issued at 138 AM EDT Thu Oct 16 2025 The main question into the early morning hours will be potential development of fog at TRI. Confidence is not as high as last night, so BCFG was maintained, but actual reductions at the terminal are still possible. Otherwise, VFR will persist through the day with northerly to northeasterly winds of around 10 kts. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 79 53 81 59 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 75 49 77 56 / 0 0 0 0 Oak Ridge, TN 75 49 76 55 / 0 0 0 0 Tri Cities Airport, TN 70 40 72 50 / 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...BW AVIATION...BW