Don't Believe The Lie

KEY MESSAGES

Updated at 631 AM CDT Wed Aug 12 2026

- Dangerous heat expected through the weekend with triple digit heat indices west of the Cumberland Plateau.

- Low to medium thunderstorm chances primarily east of I-65 each afternoon and evening through Thursday.

Stronger storms will be capable of damaging winds and heavy rain.

- Drier and even hotter conditions favored Friday through the weekend followed by some minor relief early next week.

SHORT TERM

(Tonight through Thursday Night) Issued at 1002 PM CDT Tue Aug 11 2026

High pressure continues building across the Southeast while northwest flow aloft persists on the northern/western periphery of the ridge.

This keeps Middle TN in a somewhat awkward position: hot and humid at the surface with enough mid-level support and surface instability for diurnal convection, especially east of I-65 and across the Plateau.

Wednesday will be another hot day.

Highs mainly mid-90s west of the Plateau, with dewpoints remaining in the lower to mid 70s.

Heat index values are expected to reach 105-110 in many locations, supporting continuation of the Heat Advisory.

CAMs and short-term model guidance continue to indicate the potential for an MCS or organized cluster of storms to track south/southeast into the area during the afternoon and evening, with the best chances east of I-65. Sufficient DCAPE, steep low-level lapse rates, and available moisture support a conditional risk of damaging wind gusts and locally heavy rainfall with any stronger storms that do develop or move into the region.

Coverage is expected to remain scattered at best; overall severe and flooding risk remains low but non-zero.

Any activity that does develop should diminish overnight.

Thursday looks similar but with the ridge axis shifting a bit farther north.

Highs again in the mid to upper 90s west of Plateau with heat indices in the mid to upper 100s.

Storm chances trend a bit lower than Wednesday as the ridge influence strengthens, but isolated to scattered storms remain possible, again favored east of I-65 through the afternoon and evening.

Overnight lows both nights remain warm, generally in the mid to upper 70s with little relief from the humidity.

Overall, the short-term features the dual hazards of heat and low to medium thunderstorm risks.

Confidence is higher in the heat and less on exact storm coverage/timing given typical CAM variability in this pattern.

LONG TERM

(Friday through next Wednesday) Issued at 1002 PM CDT Tue Aug 11 2026

The upper ridge is expected to build more fully overhead through the weekend, suppressing deeper moisture and convective chances while allowing temperatures to climb further.

Friday through Sunday will be the hottest stretch.

Highs are forecast in the upper 90s for many locations west of the Plateau, with the NBM and ensemble guidance showing a solid chance (around 80% for the Nashville area) of reaching or exceeding 100 deg on Saturday and Sunday.

Prolonged heat indices of 105-110+ combined with warm overnight lows in the 70s will produce major to extreme heat risk.

The Heat Advisory is already extending through Friday evening and will likely need further extension or expansion depending on trends.

Precipitation chances drop to low or near zero Friday through the weekend as the ridge dominates.

Any isolated activity would be diurnally driven and limited.

Early next week, guidance indicates the ridge begins to shift or weaken as a boundary approaches from the north, which should bring modest cooling and a return of higher rain chances later in the period.

Exact timing of the pattern change remains somewhat uncertain beyond early next week, but the multi-day heat wave itself has good support across deterministic and ensemble guidance.

Residents should continue heat safety measures: limit outdoor activity during peak heating hours, stay hydrated, check on vulnerable individuals, and never leave people or pets in vehicles.