Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
055 FXUS64 KMRX 220551 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1251 AM EST Sat Nov 22 2025 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 1229 AM EST Sat Nov 22 2025 - Showers and a few thunderstorms early this morning, with clearing skies this afternoon. A few strong storms are still possible mainly in the northern Plateau counties. - Mild temperatures continue through the weekend and the first part of next week. - Another system brings rain to the area Tuesday/Wednesday, followed by colder temperatures for Thanksgiving. && .DISCUSSION... Issued at 1229 AM EST Sat Nov 22 2025 A warm front has lifted north of the region with some light rain lingering in portions of southwest North Carolina and southwest Virginia. An additional surface boundary stretches along the Ohio River with a notable shortwave impulse aloft. This shortwave will translate across the Ohio River Valley and towards the central Appalachians, driving the aforementioned front through the forecast area late tonight/early Saturday morning. Additional scattered showers and a few thunderstorms are expected with this feature. Relative to the previous synoptic hour runs, the 00Z HRRR and NAM3k keep the shortwave ever so slightly further north and a tad more progressive. These latest models runs suggest the greatest coverage is expected along and north of I-40 in closer proximity to the upper level dynamics. Between hi-res soundings and HREF ensemble mean, it is generally expected for there to be around 400-800J/kg of MUCAPE among a strong but largely unidirectionally sheared environment. While the timing of these storms of just before or around sunrise is typically unfavorable in a diurnal sense, soundings do show weak surface based CAPE between 200-400J/kg at times. Because of this, isolated damaging wind threat and the very low potential for a brief and weak tornado cannot be totally ruled out. Latest updraft helicity tracks from the HRRR and NAM highlight the northern plateau with the greatest potential to see a brief spin-up. Overall, timing of this low end severe threat looks to be around 9-13Z(or 4 to 8 AM ET), in which the shortwave impulse will then depart the region. A few light showers may pop-up around mid day as the front moves through the region, but no sig weather is expected. Slight cooling trend into Sunday as high pressure settles into the region promoting dry weather into the new work week. The next system looks to occur Monday night through Tuesday night as surface low pressure develops near the northern Great Lakes Region. A period of isentropic lift and a shortwave will bring initial rain chances Monday night, followed by the main longwave trough and a cold front Tuesday night. NBM probabilities of 1" or more of rain increase to 30-50% for a portion of the area, mainly south of I-40. Will keep an eye on the potential for some gusty mountain winds with this system as well. Cooler than normal temperatures and dry conditions will follow. && .AVIATION... (06Z TAFS) Issued at 1229 AM EST Sat Nov 22 2025 Low end LLWS around 30 knots can be seen on the Morristown radar and will likely affect TRI and TYS. A mix of IFR and MVFR conditions are likely through the morning hours. Showers with a few thunderstorms will move into the region in the early morning hours. Clearing skies are expected by late morning or early afternoon behind a frontal passage. Light winds will become northwesterly by this evening. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 75 50 69 44 / 20 10 0 0 Knoxville McGhee Tyson Airport, TN 72 48 65 41 / 40 10 0 0 Oak Ridge, TN 71 46 65 40 / 40 10 0 0 Tri Cities Airport, TN 67 45 60 35 / 70 20 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...KRS AVIATION...McD