Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
358 FXUS64 KMRX 211844 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 244 PM EDT Fri Aug 21 2026 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 225 PM EDT Fri Aug 21 2026 - This afternoon and evening, scattered showers and storms are expected in Northeast Tennessee, Southwest Virginia and the East Tennessee Mountains. Elsewhere, showers and storms will be more isolated. - Mostly dry conditions with near normal temperatures through the weekend and early next week. && .DISCUSSION... Issued at 225 PM EDT Fri Aug 21 2026 Cu have developed across the region. Scattered showers have popped up along the TN/KY border - these should gradually drift eastward over the afternoon hours. Additional showers and storms develop this afternoon with coverage limited to isolated to widely scattered at best. Storm motions will vary given weaker flow aloft. Any outflow boundaries could spawn additional showers and storms. Severe weather is not expected this afternoon, but brief downpours and gusty winds will be possible with any passing shower. An isolated severe wind report cannot be ruled out. We`ll dry out after sunset with winds becoming calm. The development of patchy dense fog is likely in low lying areas & locations near bodies of water. Temperatures will top out this afternoon near normal, in the 80s, with cooler/drier air on tap for the upcoming weekend. We get a brief break from the excessive humidity this weekend into early next week. Mostly dry and seasonable temperatures on are tap for Saturday and Sunday as a sfc high pressure builds into the region. This high pressure will usher in drier air from the north- central NOAM. Temperatures gradually rebound back toward normal mid- week. That means the return of more humid weather & rain chances too. Northwesterly flow aloft will provide a continuous flow of weak shortwaves mid-week through the end of the work week. The NBM PoPs are generally 20-40 percent range next Wednesday thru Friday, peaking in the afternoon hours, but not widespread rain event on the horizon. && .AVIATION... (18Z TAFS) Issued at 225 PM EDT Fri Aug 21 2026 Immediate concern will be the scattered showers and thunderstorms this afternoon. Low confidence due to limited coverage, but all sites may see a brief period of TSRA this afternoon. May need to AMD on the fly to address this. Beyond this TS threat, there is a signal for patchy fog development overnight as skies clear and winds turn light to calm. KTRI and KTYS have the best signal for FG development. Winds turn more WSWerly after sunrise with SCT high clouds and a return to VFR. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 70 93 68 91 / 0 0 10 0 Knoxville McGhee Tyson Airport, TN 69 89 66 86 / 20 10 20 0 Oak Ridge, TN 68 90 64 87 / 10 10 10 0 Tri Cities Airport, TN 65 84 63 81 / 30 20 30 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...BH AVIATION...BH