Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
145 FXUS64 KMRX 031334 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 834 AM EST Wed Dec 3 2025 ...New UPDATE... .KEY MESSAGES... Updated at 823 AM EST Wed Dec 3 2025 - Dry weather today and Thursday before increasing precipitation chances late Thursday into Friday. - Moderate chances for light snowfall across extreme northeast TN and southwest Virginia early Friday morning. Low probability light freezing rain/wintry mix central TN valley. Minor impacts possible. - Very low probability of rainfall this weekend. && .UPDATE... Issued at 823 AM EST Wed Dec 3 2025 Cloud cover is expected to linger into the early afternoon hours as lingering moisture remains trapped below an inversion. There is some hope for clearing mid to late afternoon, starting in the south then moving northward. Unfortunately, due to the persistent cloud cover I had to lower afternoon temps by a few degrees. && .DISCUSSION... Issued at 1230 AM EST Wed Dec 3 2025 Low-level moisture still locked in across the region. Though the moisture is shallow, NAM soundings show moisture up to around -8 to -10 degrees Celsius. This aligns with the reports from earlier this evening of a few light flurries/snow showers across our northern areas. Because moisture is lingering, made an increase to sky cover through the rest of the night and late morning. The NBM wanted to clear things out way too fast. Sunny skies by this afternoon. Then, dry weather through Thursday with below normal temperatures. As we have been discussing, we are still watching an incoming system on Thursday night into Friday. We still aren`t in range of the Hi- Res models, but the rest of the model data suggests moderate probabilities of some light snow up across extreme northeast TN and into portions of southwest VA, as well as portions of the east TN mountains. LREF probs from DESI show between a 40 to 60% probability of seeing at least 0.5 inches of snow across these areas. The higher- end probs (60s) are along the TN/NC border up in northeast TN and into the eastern portions of Washington County, VA. Whereas locations between Rogersville and Tri-Cities are more in the 30 to 40% prob range. Upping the snow amounts to 1" drops the probabilities to around 40% for extreme northeast TN and eastern Washington County, VA. LREF Probs for trace amounts of freezing rain or light wintery mix across the central TN valley is around 30%. Areas south of Knoxville should be all rain. The opportunity for any snow accumulation across northeastern areas will be short- lived though. Increasing southerly flow will bring about warming temperatures, transitioning any frozen precip over to rain by late morning/early afternoon. Low confidence forecast through the rest of the period. Some models show a dry Saturday, while the latest NAM and ECMWF keep light showers in place. Latest NBM keeps slight chance POPs in through Saturday. Slight chance/chance Pops then remain in place through the rest of the period due to an active pattern across the U.S. This makes it difficult to pinpoint exactly when and where any one system will be moving through the the flow. Thus, this is why the NBM is hanging onto Pops beyond the weekend. && .AVIATION... (12Z TAFS) Issued at 616 AM EST Wed Dec 3 2025 Based on the latest trends and latest data, MVFR ceilings are now expected to last longer into the day than the previous issuance. CHA is still likely to improve first by around noon. The other two sites, however, could remain MVFR through the afternoon. Winds will be fairly light and shifting to be more westerly. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 46 31 49 37 / 0 0 10 70 Knoxville McGhee Tyson Airport, TN 43 29 45 33 / 0 0 10 60 Oak Ridge, TN 44 28 45 32 / 0 0 0 60 Tri Cities Airport, TN 41 26 43 29 / 0 0 0 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...99 AVIATION...McD