textproduct: Morristown

KEY MESSAGES

Updated at 715 PM EDT Sat Sep 12 2026 - Scattered to numerous showers and thunderstorms across the area today, capable of some gusty winds and heavy rains. Some localized flash flooding wouldn't be out of the question.

- A return to upper ridging aloft, and subsequent hot temperatures, appears likely for this coming week.

DISCUSSION

Issued at 237 PM EDT Sat Sep 12 2026

A shortwave trough will be moving from Middle Tennessee eastward through the southern Appalachians this afternoon into tonight. Ahead of this feature, widespread showers, with some embedded thunderstorms, are ongoing across the Cumberland plateau and the Tennessee valley. Do not believe there's much of a risk of any severe storms today, as instability is somewhat limited (MLCAPE values are on the order of about 1,500 J/kg). A couple of stronger storms capable of winds in the 40-50 mph range could occur, but overall the threat is limited I think. Additionally, PWATs are quite high (between 1.8 and 2.0" across our CWA) so heavy rains and some localized flooding issues could arise if there is any training of convection. This appears to be a limited threat as well, given storm motions, but worth keeping an eye on for sure.

The shortwave shifts east of the forecast area by late this evening and the overnight hours. We likely keep some lingering showers, especially in the northern mountains thanks to aided lift from increasingly upslope flow, into the morning hours on Sunday. But otherwise we should see increasingly dry conditions to finish out the weekend.

Afterwards, upper ridging builds back into the region, with little to no chance of rain outside of perhaps the East Tennessee mountains, and afternoon temperatures rising firmly back into the upper 80s to mid 90s by Tue/Wed of this coming week.

We'll have to wait and see how the latter part of the week shapes up. Currently some deterministic guidance bring an upper low from off the southeast coastline, westward across northern Florida and into the Gulf. This would weaken the ridge and could lead to much better rain chances across the area. But suffice it to say the details would matter greatly, so for now the forecast just shows a gradual increase in rain chances towards the end of next week.

AVIATION

(00Z TAFS) Issued at 715 PM EDT Sat Sep 12 2026

Rain is exiting the area to the east, and cloud cover will follow over the next few hours. Clearing skies and calm winds will favor fog and low clouds developing later tonight, mainly after midnight, at all sites. Confidence is high that LIFR conditions or lower will develop. Confidence is lower in whether it will be fog or low cigs, but both are possible. Gradual return to VFR conditions is expected by noon tomorrow.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 89 70 94 70 / 70 10 0 0 Knoxville McGhee Tyson Airport, TN 84 69 90 69 / 80 20 0 0 Oak Ridge, TN 85 68 90 68 / 80 20 0 0 Tri Cities Airport, TN 80 66 85 65 / 80 30 10 0

MRX WATCHES/WARNINGS/ADVISORIES

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