textproduct: Morristown

KEY MESSAGES

Updated at 732 PM EDT Mon Sep 21 2026

- Well above normal temperatures to persist through Tuesday. But relief is on the way, with a pattern change expected mid-week and much cooler temperatures to follow.

- Scattered to numerous showers are expected Monday through Wednesday.

- A few strong to severe storm with damaging winds could occur Monday, with damaging winds being the primary threat. Localized flooding will be possible each day through Wednesday as well.

DISCUSSION

Issued at 204 PM EDT Mon Sep 21 2026

Currently a few thunderstorms out there, but also some scattered clouds in the southern valley from morning/early afternoon convection. Low confidence on location and coverage of expected storms this afternoon as CAMs have been exceptionally poor with morning convection and afternoon initialization. If/when storms do form then the atmosphere should support fairly robust thunderstorm growth, with the strongest storms capable of producing damaging winds/microbursts, small hail, and isolated flooding as they'll be moving very slow. A similar set up is in place for tomorrow as well.

On Wednesday the pattern change gets underway and we begin to see a break in the relentless heat. By Wednesday a rex block pattern takes shape as an upper ridge builds over the Canadian side of the Great Lakes region, and the aforementioned Ohio valley upper low deepens over the Ohio valley and central Appalachian region. With the upper low to our north and NW flow aloft, this will push the cold front through the southern Appalachians and allow the cooldown to begin. By Thursday through the weekend we should see highs topping out only in the 70's for every except southeast TN where they may squeak across the 80 degree mark. This pattern will also be fairly dry with a more Canadian airmass moving in.

AVIATION

(00Z TAFS) Issued at 732 PM EDT Mon Sep 21 2026

Will have some SHRA/TSRA INVOF KTRI through 01z, but afterwards I expect the remainder of the night to be free of convection for all terminals. Some additional convection could pop up overnight, but confidence in where exactly that occurs is too low to include in the TAFs at this time. Otherwise, for tonight, expect fog once again at KTRI, especially in light of them receiving rainfall at/near the terminal this evening. Have played it similar to last night, with prevailing 3SM and a TEMPO down to 1SM. Didn't go lower as we may have some lingering mid and high clouds which could disrupt the fog some. For tomorrow, storm coverage should be similar or higher, but still not expecting wall to wall coverage so just have a PROB30 in at all sites for now.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 70 91 68 86 / 50 70 30 60 Knoxville McGhee Tyson Airport, TN 69 87 67 82 / 50 70 50 80 Oak Ridge, TN 68 86 66 82 / 40 70 40 70 Tri Cities Airport, TN 65 82 63 77 / 60 80 70 80

MRX WATCHES/WARNINGS/ADVISORIES

NC...NONE. TN...NONE. VA...NONE.