Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
637 FXUS64 KMRX 211119 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 719 AM EDT Fri Aug 21 2026 ...New AVIATION... .KEY MESSAGES... Updated at 710 AM EDT Fri Aug 21 2026 - Isolated showers and storms are possible through the early morning hours. - 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 135 AM EDT Fri Aug 21 2026 In the upper levels, a trough is over the Ohio Valley, extending down to Florida. At the surface, a weak cold front or stationary boundary stretches from the KY/VA border into West TN. Strong to severe storms near the TN/AL border are starting to weaken. This activity may get into the Central TN Valley before it dissipates completely. The CAMs have isolated showers and storms continuing into the morning hours. This afternoon and evening the trough will still be over the Ohio Valley but the surface boundary will likely be a little farther downstream either over the Tennessee Valley or farther east over the North Carolina mountains and into NW Georgia. The CAMs show that showers and storms will be more scattered in NE Tennessee, SW Virginia and the East Tennessee mountains this afternoon and evening. Elsewhere, storms will be more isolated. The SPC Outlook keeps the marginal severe risk to our east over North Carolina. The exact placement of the boundary will be a factor in whether or not we have strong storms on this side of the mountains. Shortly after sunset this evening showers and storms will dissipate. This weekend, a deep trough will be over the East Coast but the trough axis will be well to our east. Therefore, the weekend will be mostly dry. Temperatures will be near normal. The NBM has low rain chances early next week increasing to 40-50% chances by midweek. The pattern will be similar but the trough over the East Coast will lift to the north early in the week. The ridge to the west will be centered over the Rockies. A shortwave may move through the pattern midweek. && .AVIATION... (12Z TAFS) Issued at 710 AM EDT Fri Aug 21 2026 TS early this morning is progressing smoothly to the northeast and should be out of the area within roughly the first hour of the period. Today is expected to be VFR skies with light winds less than 10 knots. A low chance for additional showers or TS is possible in the afternoon, maintained a PROB30 at KTRI for that possibility. Odds are remote near KTYS and not expected at KCHA. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 92 71 93 69 / 20 0 0 0 Knoxville McGhee Tyson Airport, TN 88 69 88 67 / 40 20 10 20 Oak Ridge, TN 87 68 89 65 / 40 10 0 10 Tri Cities Airport, TN 84 65 83 63 / 80 40 30 30 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...McD AVIATION...Wellington