textproduct: Morristown

KEY MESSAGES

Updated at 226 PM EDT Sun Jun 21 2026

- Showers and storms are likely on Monday, with the potential for strong/severe storms in the afternoon/evening. Multiple rounds are possible and timing remains uncertain.

- Dry weather Tuesday and Wednesday, then daily rain chances return late in the week, with temperatures near normal.

DISCUSSION

Issued at 226 PM EDT Sun Jun 21 2026

The remnants of the ongoing convection/MCS over MO/IL will reach our area late tonight. Over the last several runs, models have been in poor agreement and shown poor consistency with the timing and intensity of the remnant convection as it nears our area. We can generally expect that a 4-8 AM time frame is likely for showers in our northern Plateau counties, and that a severe threat is unlikely as the approaching cold pool outflow encounters an unfavorable environment in East TN. Any showers/storms will be elevated with weak lapse rates aloft, and likely won't last very far past I-75.

As we have discussed the last several days, the question remains how this morning activity will affect a second round of showers/storms ahead of the cold front in the afternoon/evening. Again, model agreement/consistency on the details has been poor, but the depiction of another round of stronger showers/storms continues for Monday afternoon, possibly two rounds according to the HRRR. During this time, HREF probabilities of CAPE > 1000 j/kg and shear > 25 kt are in the 25-50% range - not super impressive at all but adequate for a few strong to severe storms. A 35-40 kt LLJ could mix down with downbursts. 0-3 km shear is mostly uni-directional but any boundaries that interact with storms could lead to a brief and isolated tornado, mainly in southern sections. The flash flood threat remains as training cells in the uni-directional flow could cause problems, but the progressive movement of storms in the westerly flow should keep the problems isolated, so no Flood Watch appears necessary at this time. Timing appears to be 2-10 PM for most of the storms along a pre-frontal trough and upper divergence maximum, with a chance of showers persisting overnight until the surface front pushes through Tuesday morning. NBM PoPs appear way too high for the post-frontal and NW flow environment on Tuesday, and will be cut back.

Wednesday will be dry with a large surface high covering the central and southern Appalachians, and a building midlevel ridge from the west. A low pressure system tracking across the upper Midwest and Great Lakes brings rain chances back to the area on Thurday. A broad trough over the eastern Conus through the weekend could bring a few disturbances to the area, so low chance PoPs will be in the forecast each day.

AVIATION

(18Z TAFS) Issued at 110 PM EDT Sun Jun 21 2026

VFR conditions and winds less than 10 kt from the SW will continue through the afternoon and evening. Clouds are expected to increase late tonight, likely in the MVFR-VFR margins. CHA appears most likely to have MVFR cigs, with lower chances at TYS and even lower at TRI. Some gusty SW winds are expected to develop late this TAF period at TYS and TRI, mainly 20-25 kt gusts.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 73 87 70 85 / 30 80 70 10 Knoxville McGhee Tyson Airport, TN 72 86 68 82 / 30 90 80 10 Oak Ridge, TN 71 85 67 83 / 50 90 60 0 Tri Cities Airport, TN 66 85 65 80 / 10 80 90 20

MRX WATCHES/WARNINGS/ADVISORIES

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