171 FXUS64 KMRX 170216 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1016 PM EDT Wed Apr 16 2025 ...New UPDATE... .UPDATE... Issued at 1013 PM EDT Wed Apr 16 2025 Forecast remains in good shape this evening with just some minor touch ups to the hourly T/Td trends based on latest surface observations. A quiet but cool overnight is expected. && .SHORT TERM... (This evening through Thursday) Issued at 300 PM EDT Wed Apr 16 2025 High pressure now lies over the forecast area. A weak surface trough was just across the Appalachians in NC. The pressure gradient was relaxing but with the trough to the east there was still some gusty winds over southwest Virginia and northeast Tennessee. Good mixing has allowed dew points to drop into the upper 20s to around 32. Relative humidity values are in the 20s today somewhat higher than on Tuesday but still low. Kept dew points low through about 7pm with RH values 20 to 25 percent over much of the area. Then rise slowly tonight as temperatures drop quickly and winds decouple. Temperatures this afternoon are in the 60s which is a few degrees warmer in most places than Tuesday. For tonight and Thursday winds decrease as high pressure shifts east and will be over the southern Appalchians late tonight and Thursday morning. Some frost will form across mainly southwest Virginia and northeast Tennessee with lows in the mid to upper 30s. Also southwest North Carolina will drop into the upper 30s with patchy frost there. A weak warm front will move northward later Thursday morning through the afternoon from southwest to northeast and produce some sprinkles and possible light showers. Do not expect any significant rainfall. Temperatures may be held down slightly in the northeast. Otherwise high temperatures closer to the average of upper 60s to near 70 northeast to lower to mid 70s central and southwest. For fire weather Thursday expect RH values as low as 25 percent in spots but mostly around 30 percent, could be higher with more clouds north. && .LONG TERM... (Thursday night through next Wednesday) Issued at 300 PM EDT Wed Apr 16 2025 Key Messages: 1. Warming trend Friday. 2. Potential for weak system late Sunday into Monday, timing uncertain along with exact impacts, but next good chance for at least scattered showers and thunderstorms. Discussion: Increased cloudiness near enhanced vorticity on Thursday will attempt to spark some high based showers. Looks unlikely that any of it reaches the ground between the combination of brief coverage, weak forcing, and low level dry air turning anything that falls into likely virga, but cannot completely rule out some drivers having to turn on their wipers once or twice. Ridge of high pressure anchors itself off the southeastern coast by Saturday and plays a significant role in maintaining a pleasantly warm regional atmosphere over our area from the weekend onwards into next week. NBM keeps slight chance PoPs in on a SW to NE tangent along the western and northern edges of Tennessee and Virginia over the weekend. If the deterministic guidance is any clue, we might be drier than that area wide, keeping rain chances off further west, at least until sometime later on Sunday. A weak upper shortwave will then attempt to bring a cold front into the area late Sunday into Monday timeframe, this should help spark showers and storms ahead of the front. Not certain this front will be able to push through or just wash out entirely leaving a warmer pattern in place. Beyond Monday, the upper ridge offshore is likely to flatten out, as depicted by both ensemble means. && .AVIATION... (00Z TAFS) Issued at 737 PM EDT Wed Apr 16 2025 Winds will become light and variable tonight with VFR conditions through the TAF cycle. High to mid-level clouds will be around at times, most notably tomorrow afternoon, as a weak front progresses across the region. Rain chances are less than 20%, thus, no mention has been included at this time. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 45 75 53 83 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 41 72 51 83 / 0 10 0 0 Oak Ridge, TN 41 72 50 81 / 0 10 0 0 Tri Cities Airport, TN 36 69 48 81 / 0 10 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...TD AVIATION...KRS