textproduct: Morristown

KEY MESSAGES

Updated at 650 AM EDT Wed Aug 12 2026

- Periods of showers and thunderstorms will be possible each day through the end of the work week. Localized flooding and strong wind gusts will be possible with storms at times.

- Temperatures will be near normal Wednesday and Thursday, with a gradual warming trend and into the weekend.

DISCUSSION

Issued at 243 AM EDT Wed Aug 12 2026

The MCS bringing us this past evenings activity has passed over the TN/GA border with light stratiform rain persisting across portions of the forecast area in its wake. Overall, the threat for organized strong to severe storms and new flash flooding has diminished for the overnight, however, be cautious for any lingering flood issues as we continue into these early morning hours.

Additional periods of showers and storms are expected today through Friday as we remain in a predominant northwest flow pattern beneath the transition zone of a strong ridge axis to our west and a trough axis to our north and east. Comparing latest radar trends to the 00Z HREF Suite, NAM3km seems to be initializing the best with some additional CI and an associated vort lobe across eastern Indiana.

The CAMs that do seem to depict this activity to a varying extent suggest some additional scattered showers and thunderstorms move through the area by about 12Z this morning. Quite honestly, I have little confidence in how this convection may play out. That being said, we have some very low 1hr FFGs between 0.9 to 1.3 inches due to the evolution of this past evenings precip. Morning instability should be fairly limited, so the strong to severe threat is low but perhaps not zero depending how the intensity of the disturbance evolves. The main threat may be focused on the potential for some additional flash flooding, particularly for those very worked over locations in our central and northern areas. Have introduced a short fuse Flash Flood Watch due to the poor antecedent conditions.

CAMs then generally want to dry us out for much of the mid-afternoon, with an additional round of showers and storms possible in the late evening to early overnight. Cannot rule out some additional flooding concerns or even the potential for isolated strong to severe storms depending on how well we destabilize in the afternoon. Did not feel confident enough in how this second round of activity could develop to cover that with the Flash Flood Watch, but depending on how things evolve it isn't out of the realm of possibility an extension is needed.

Again, additional periods of showers and storms are possible Thursday and Friday. The shortwaves look to be relatively weaker so the potential for strong/svr storms seems relatively lower, though not zero. We will also start to see an increase in upper-level heights by Friday and this will translate to a slight warming trend. Central and southern areas may be looking at Heat Advisory criteria as we head into this late week/weekend period. While we cannot totally rule out some diurnal pops, additional organized convection is unlikely. This pattern is expected to continue into next week extent but perhaps with temperatures a few degrees cooler comparative to the weekend.

AVIATION

(12Z TAFS) Issued at 650 AM EDT Wed Aug 12 2026

Confidence in timing of convection for the 12z TAF period is not very high. That said, it appears we should have two rounds of convection today. One this morning, and then another after 04z tonight. Ongoing convection in SE KY should be INVOF KTRI by 13z and it's close enough to confidently go with a TEMPO group there. Further south, there's uncertainty in how well this will hold together, so just have PROB30 groups for this initial round at KTYS and KCHA. For the evening round, confidence is a bit lower still so just PROB30 for that round at KTRI and KTYS. Arrival time is late enough to preclude mention of it at KCHA. In terms of flight categories, morning IFR CIGS will lift as showers move in. Expect Mostly VFR after that, with occasional MVFR conditions in convection.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 93 74 95 75 / 40 20 30 0 Knoxville McGhee Tyson Airport, TN 91 73 92 76 / 50 50 40 10 Oak Ridge, TN 91 72 92 74 / 50 40 40 10 Tri Cities Airport, TN 87 69 88 71 / 50 40 40 20

MRX WATCHES/WARNINGS/ADVISORIES

NC...NONE. TN...Flood Watch until 3 PM EDT this afternoon for Anderson-Blount Smoky Mountains-Campbell-Claiborne-Cocke Smoky Mountains- Grainger-Hamblen-Hancock-Hawkins-Jefferson-Johnson-Knox- North Sevier-Northwest Blount-Northwest Carter-Northwest Cocke-Northwest Greene-Scott TN-Sevier Smoky Mountains- Southeast Carter-Southeast Greene-Sullivan-Unicoi-Union- Washington TN.

VA...Flood Watch until 3 PM EDT this afternoon for Lee-Russell-Scott VA-Washington VA-Wise.