Subsidence Crushes Everything
Wednesday, August 12, 2026 · 10:09 PM
Lyrics
Dangerous heat expected through the weekend with triple digit heat indices west of the Cumberland Plateau. Lower thunderstorm chances Thursday, but any stronger storms will be capable of damaging winds and heavy rain. Drier and hotter conditions favored Friday through the weekend followed by some minor relief early next week. The upper ridge expands across the Southeast Its crushing weight begins to exert control Weakening the northwest flow aloft The ridge axis creeps closer to devour the land West of the Cumberland Plateau Temperatures climbing to the mid to upper nineties Dewpoints hold in the lower to mid seventies Moisture trapped beneath an iron sky Peak heating arrives with nowhere to hide And the heat risk rises One hundred five to one hundred ten The heat index rises again and again Mid-level subsidence seals the tomb One hundred five to one hundred ten By Friday the ridge strengthens its grip Mid-level subsidence smothers every cloud Precipitation chances fall away As humidity wraps us in a heavy shroud Overnight lows trapped in the mid to upper seventies No relief when the night descends One hundred five to one hundred ten The heat index rises again and again Mid-level subsidence seals the tomb One hundred five to one hundred ten No overnight recovery No relief in the dark The subtropical ridge reigns supreme One hundred five to one hundred ten
The forecast discussion
NEW SHORT TERM, LONG TERM
KEY MESSAGES
Updated at 956 PM CDT Wed Aug 12 2026
- Dangerous heat expected through the weekend with triple digit heat indices west of the Cumberland Plateau.
- Lower thunderstorm chances Thursday, but any stronger storms will be capable of damaging winds and heavy rain.
- Drier and hotter conditions favored Friday through the weekend followed by some minor relief early next week.
SHORT TERM
(Tonight through Friday Night) Issued at 956 PM CDT Wed Aug 12 2026
An expanding upper ridge over the SE will continue to exert greater influence across Middle TN. Residual NW flow aloft will weaken as the ridge axis shifts closer, limiting organized convective systems.
Thursday will feature another round of hot and humid conditions.
Afternoon highs should reach the mid to upper 90s west of the Plateau, with dewpoints holding in the lower to mid 70s.
This combination will push heat index values into the 105-110 range. isolated showers or thunderstorms can't be ruled out during peak heating, but overall coverage looks sparse.
Any storms that do form will still have strong instability available and could produce brief gusty winds or heavy downpours.
Overnight lows will remain elevated in the mid to upper 70s with persistent humidity.
By Friday the ridge influence strengthens further.
Increased mid level subsidence should keep the area dry, with precip chances diminishing.
Highs edge a bit higher into the upper 90s and heat indices stay in the mid to upper 100s.
Little overnight relief is expected heading into the weekend.
LONG TERM
(Saturday through next Thursday) Issued at 956 PM CDT Wed Aug 12 2026
The subtropical ridge is forecast to become well established overhead this weekend, delivering the hottest stretch of the period.
Highs from Saturday through monday are expected to climb into the upper 90s to around 100 or slightly higher in some locations west of the Plateau.
Recent NBM and ensemble guidance indicate solid probabilities of reaching or exceeding the 100 deg mark on the warmest days.
Afternoon heat indices of 105 to 110 will be common, and warm overnight lows in the mid to upper 70s will limit recovery, maintaining major to extreme heat risk.
Rainfall chances remain very low through the weekend and into early next week as dry air and subsidence aloft suppress most convective development.
Any activity that forms would be isolated and short lived.
Toward the middle of next week, global models suggest the ridge may begin to shift or weaken as a northern stream feature approaches.
This evolution should allow temperatures to moderate somewhat and open the door for increased precipitation chances, though the precise timing beyond Days 5/6 still carries some uncertainty.