textproduct: Morristown

KEY MESSAGES

Updated at 138 AM EDT Wed Sep 23 2026

- Scattered to numerous thunderstorms today, with lighter rain showers on Thursday. A low chance for flash flooding exists with any prolonged heavy rainfall today.

- Comfortable early fall weather with no rain chances beginning Friday and persisting through the weekend.

DISCUSSION

Issued at 138 AM EDT Wed Sep 23 2026

Here in southern Appalachia, we're getting another bout of homegrown showers and thunderstorms today. A diving trough cutting to the southeast underneath a Rex block will combine a good vort max, some mild upper divergence, and warm and moist air to produce another round of scattered to numerous thunderstorms later today. Effective shear is present underneath all that, around 20 knots, deep layer shear a little stronger, so depending on the storms it's possible there's one or two severe storms for wind gusts, though I'm not as sold on a severe hail risk. Otherwise storm motions are forecast to be near 10 knots, so slow moving storms do present a risk for flash flooding, especially if on previously saturated soils or vulnerable soils. Both 00z REFS and 00z HREF depict heavy rain swaths enough to induce flash flooding in the mountain counties south of Knoxville for today, but I wouldn't take the exact locations as gospel. Thursday skinny and somewhat shallow vertical profiles will still support a few showers, with perhaps more scattered light rain under the still moist atmosphere.

Chattanooga. Congratulations. After 50 days of 90F or hotter weather, you have attained the next part of the year: still warm but not excruciatingly hot. Possibly even more shocking are the low temperatures, after 100+ days of minimums being 60F or greater, Chattanooga will hit the 50s beginning this weekend.

GFS/Euro are in agreement that we'll be on the backside of a solid nor'easter on the Eastern seaboard this weekend, which means we'll be on the receiving end of dry continental air while that storm system matures off the New England coast. Might have a few overperforming radiation nights this weekend in Virginia, skies look to be clear in the low PWAT environment with very dry air present. It is conceivable that a few colder hollows might get into, gasp, the upper 30s Saturday and Sunday mornings! First taste of fall has arrived. Daytime afternoon RH values are likely to lead to a very pleasant weekend, which is the best benefit from dry air plus still mildly warm temperatures.

AVIATION

(06Z TAFS) Issued at 138 AM EDT Wed Sep 23 2026

MVFR to IFR cigs will continue to expand into region overnight. The combination of low cigs and some light wind should be enough to prevent much dense fog from forming. MVFR cigs look to stick around through early afternoon before they scatter out. Another round of showers and storms will develop in the afternoon and evening hours. Maintained the PROB30s given the uncertainty with coverage.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 85 65 81 61 / 80 70 30 10 Knoxville McGhee Tyson Airport, TN 81 64 76 58 / 90 90 60 10 Oak Ridge, TN 80 63 76 57 / 90 70 60 0 Tri Cities Airport, TN 76 57 71 50 / 70 80 10 0

MRX WATCHES/WARNINGS/ADVISORIES

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