textproduct: Morristown

KEY MESSAGES

Updated at 737 PM EDT Tue Aug 11 2026

- Showers and thunderstorms will be possible each day through the end of the work week, with the best chance of rain during each afternoon.

- There will be potential for a few storms to become strong to severe each afternoon with damaging winds and localized flooding the main threats.

- Temperatures will be near normal through Friday, but trending slightly above normal for the weekend.

DISCUSSION

Issued at 218 PM EDT Tue Aug 11 2026

The regional radar mosaic shows multiple areas of convection upstream over the Ohio Valley and southern Great Lakes. The exact evolution of these structures is uncertain, but the likelihood of one of these structures to impact our area is high. There are a few isolated thunderstorms developing across the southwest VA ahead of the main MCS over N KY and W WV. These storms could produce isolated winds and heavy rainfall. If we see repeated rounds of storms and showers over any area, the potential for flooding and flash flooding will increase and may require flood headlines in the future. Forecast soundings across SW VA & NE TN highlight 2000-3000+ j/kg CAPE with ~20 knots of shear. This is plenty for clusters of thunderstorms to develop and produce isolated hail/wind damage. Forecast soundings further west in SE TN highlight significant instabilty available for thunderstorms to tap into. The general consensus is that we'll see the MCS or a portion of the MCS upstream follow the instability gradient that goes through our eastern forecast area of SW VA/NE TN. The instability in place will be plenty for MCS maintenance and the structure itself will likely be able to enhance the local shear environment to a more favorable situation. The timing appears to be between 4 to 8pm for our NE area with uncertainty on how far south/west it'll continue. Additional MCS over central Indiana should continue to move south-southeast and should arrive in our northern area this evening. The exact evolution of this is even more uncertain due to the unknowns with this afternoon's potential convection. There is reason to believe that the second round should maintain some intensity and bring another round of thunderstorms capable of producing damaging winds and heavy rain. This structure does have some mid level support as an impulse transits through the Ohio Valley this evening/tonight. This should move through the area this evening and into tonight before we begin to dry out. Given the general uncertainty and lower-than-normal confidence with this forecast, please monitor the forecast if you have any outdoor work or activities planned this afternoon - evening.

Wednesday through Friday... this period remains unsettled with the potential for additional showers and thunderstorms each afternoon. A strong ridge remains off to our west and a trough to our east over the NE CONUS. This places us in a favorable area for daily shower/thunderstorm chances through Friday evening. There will be a non-zero chance for a few of these storm to become strong to severe and able to produce heavy rainfall. There isn't a clear signal for any one area but rather a broad brush approach given the unstable airmass and northwest flow aloft. The finer details won't be resolved likely until the day of given the lower confidence tied to this pattern.

Saturday through Early Next Week... The western ridge axis will build into the area this weekend. This will allow warmer temperatures to settle in through the start of next week. Precipitation chances will continue through the weekend, but the chance of any organized convection will be much lower. If the ridge builds in further east, we may even stay mostly dry Saturday/Sunday, which would welcomed.

AVIATION

(00Z TAFS) Issued at 737 PM EDT Tue Aug 11 2026

An MCS is spreading into northern TN this evening, with TRI the most likely culprit to see strong gusty winds as the line of showers and storms moves through in the next hour or two. Frequent lightning and heavy rain will also accompany this activity. Convection is expected to weaken but may maintain enough of a presence to bring heavy rain and lightning to TYS and CHA later in the evening, though, confidence is lower in these locations. HREF probabilities paint 40% chance for TRI experience MVFR cigs early Wednesday morning. Additional rounds of showers and storms are possible Wednesday but confidence in exact location and timing is too low to include any mentions at this time.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 73 93 74 94 / 40 30 20 20 Knoxville McGhee Tyson Airport, TN 73 90 73 91 / 40 40 30 30 Oak Ridge, TN 72 90 72 91 / 40 30 30 30 Tri Cities Airport, TN 68 86 69 87 / 60 40 50 40

MRX WATCHES/WARNINGS/ADVISORIES

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