Shortly after midnight Sunday, the temperature started climbing in the small Texas town of Breckenridge.
At 12:15 a.m. Sunday, the temperature was 85 degrees. By 1:35 a.m., it had soared to 99 degrees, according to the National Weather Service.
At that moment, Breckenridge, 100 miles west of Fort Worth, was the hottest spot in the Western Hemisphere.
What caused this unusual event?
It was a heat burst.
When the anvil of a thunderstorm collapses, it sends air rushing to the ground. As that air races downward, it warms up, sending temperatures soaring. At Stephens County Airport in Breckenridge, wind gusts peaked at 47 mph.
"It's a fairly rare weather phenomenon," said National Weather Service meteorologist Lee Carlaw. "We don't get to actually measure them very often."
It wasn't just in Breckenridge.
Temperatures also soared in Eastland 27 miles to the south, where it reached 96 degrees.
The wind gusts were felt all along the Interstate 20 corridor, with gusts in Tarrant County reaching 40-45 mph at some stations.
While heat bursts are rare, hot weather in Texas is not.
"We'll be in the upper 90s here, close to 100, but we could see 100- to 103-degree highs west of Fort Worth from Wednesday through Friday," Carlaw said.