Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
316 FXUS64 KMRX 301104 AAA AFDMRX Area Forecast Discussion...UPDATED National Weather Service Morristown TN 704 AM EDT Tue Sep 30 2025 ...New AVIATION... .KEY MESSAGES... Updated at 700 AM EDT Tue Sep 30 2025 - Scattered showers and a few thunderstorms are possible today, focused mainly in the eastern half of the area. - Dry seasonal fall weather is expected Wednesday through the weekend. && .DISCUSSION... Issued at 1254 AM EDT Tue Sep 30 2025 The pattern consists of pinched ridging aloft over the Mississippi Valley with associated strong surface high pressure over Ontario, and an eventual eastern shift to Quebec. Tropical Storm Imelda and Hurricane Humberto almost spin in unison within troughing to our east. The only impacts we can expect from them, will be increased moisture and instability later today to support showers and thunderstorms. Best chances (40-50%) will be along the Appalachians extending from southwest VA south to southwest NC. Parts of the valley may experience anywhere from a 20-35% chance of precipitation. The most recent SPC Outlook for today circles most of our forecast area only for general thunderstorms. Persistent cloud cover today will notably keep temperatures cooler across our most eastern locations. After a couple of warmer than normal days, a dry pattern will be underway Wednesday, persisting until around the middle of the weekend. Temperatures will be a couple of degrees cooler. Drier air will also follow suit. The next chance for precipitation may not be until towards the end of the forecast period when moisture is advected north from a Gulf Coast frontal boundary. && .AVIATION... (12Z TAFS) Issued at 700 AM EDT Tue Sep 30 2025 ISOLD to SCT SHRA and perhaps a few embedded TSRA are expected across east TN this afternoon. Confidence is pretty low, but the best signals in guidance favor KTRI and KCHA seeing some. Otherwise the only concern in the 12z TAF period will be whether fog development occurs tonight. Calm winds and thinning high clouds would seem to favor it. Added in some MVFR VSBY at KTRI late tonight to account for this. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 85 64 85 61 / 20 10 0 0 Knoxville McGhee Tyson Airport, TN 82 61 83 58 / 20 10 0 0 Oak Ridge, TN 82 61 84 57 / 20 0 0 0 Tri Cities Airport, TN 74 56 80 53 / 40 10 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...KS AVIATION...CD