A new heat dome has engulfed the south-central United States, pushing temperatures back toward triple digits as the region nears the autumn equinox. This surge continues one of the most extreme warm periods on record for Texas, Oklahoma, Arkansas, and nearby states. Millions now face another week of hazardous heat, deteriorating air quality, and potential storms along the dome’s perimeter as the pattern moves east.
Heat Dome Rebuilds Over Key States
The latest dome formed over Texas, Oklahoma, Arkansas, Louisiana, and sections of the Southeast, regions where high pressure has recurrently settled since spring. Despite the sun’s weakening as the equinox approaches, temperatures are soaring 5 to 10 degrees above historical norms. Highs in the upper 80s and 90s are prevalent, with the core pushing Dallas, Austin, and Oklahoma City back toward 100 degrees through Saturday.
AccuWeather Senior Meteorologist Alan Reppert explained, “There are multiple reasons for this heat dome to persist across the southern U.S., linked to teleconnections in the Pacific unrelated to El Niño.” While El Niño influences weather patterns, other ocean-driven signals have dominated the late-summer setup.
Record-Breaking Heat Streaks
This dome overlays an already challenging season. Dallas has noted 49 days at or above 100 degrees, nearly doubling its 20-year average, while Oklahoma City has tripled its typical count. September has seen Oklahoma City with 10 triple-digit days and Dallas with 12, a rare yet not unprecedented occurrence.
Austin has experienced 43 days above 100 degrees, against a 20-year average of 29. El Paso has hit 52 such days, significantly exceeding its usual 34. Cities like Little Rock, Tulsa, and Wichita are doubling or tripling their long-term norms.
Role of Warm Oceans and El Niño
Warm ocean temperatures are reinforcing the dome’s strength. Reppert stated, “El Niño and ocean temperatures are partially responsible for this heat dome.” The warm waters off the West Coast and in the Gulf of Mexico have maintained the dome’s energy across the southern U.S.
August 2026 matched July 2023 as the hottest month ever, with global average surface temperatures reaching 16.96°C (62.5°F). Sea-surface temperatures outside polar regions hit a record average of 21.07°C, peaking at 21.11°C on August 24 and 25.
Vulnerable Populations Under the Dome
The dome spans regions prone to intense heat. “Most of Oklahoma, Texas, and Arkansas are highly susceptible,” Reppert stated. Western areas of Texas and Oklahoma, being higher in elevation, remain slightly cooler.
The dome, along with humidity and stagnant air, results in poor air quality across several states. Vulnerable groups, like older adults, outdoor workers, and those lacking reliable cooling, face increased risks.
Simultaneously, parts of the Northeast prepare for their first frost, underscoring stark regional contrasts.
Storms at the Dome’s Edges
The dome’s edges have sparked rounds of downpours and severe thunderstorms. This week, storms are expected from the Dakotas and eastern Montana through western Minnesota, the Midwest, and into the Northeast.
A storm may also form off the Atlantic coast, moving southwest across Florida into the Gulf of America. This system could produce a tropical or subtropical depression. Another area southeast of Bermuda has a medium development chance.
These edge-driven storms have marked the season, forming where hot, stationary air meets cooler regions.
Global Heat Context and Future Prospects
Reppert noted the southern U.S. heat dome’s minor role in August’s global record, as Europe experienced more significant deviations. Relief may be on the horizon. “The heat is expected to weaken late this week and over the weekend as a more active northern Pacific jet stream helps dislodge the heat dome, offering relief to the southern U.S.,” Reppert said.
Nonetheless, the summer’s impact is clear. The Lower 48 averaged 76.9 degrees in July, breaking records back to 1895, surpassing July 1936 during the Dust Bowl. With heat domes consistently reemerging since spring, the south-central U.S. has endured one of its hottest seasons on record.
Contact Newsweek editors on this story: Samantha Beech and Gray R. Thomas