More than 800 Entergy Arkansas customers were without service in Garland County Sunday morning after a decaying thunderstorm system created a "heat burst" that moved through central Arkansas overnight.
One of the largest outage areas was along North Moore Road in the western part of the county, affecting more than 600 customers.
Entergy was estimating that power would be restored by noon Sunday; by the afternoon, only a handful of outages remained.
"Due to the thunderstorms along with the high winds that have and continue to move through the area we are experiencing numerous outages. Entergy personnel are working to restore service as quickly as safely possible. At this time, we estimate that all service will be restored by noon, Sunday. The estimated time of restoration could change as all damage assessments are completed or if other storm activity results in additional outages," the utility posted on its outage website.
The "heat burst" moved across portions of central Arkansas as the result of decaying large thunderstorm complex, the National Weather Service posted Sunday morning on its Facebook page. At Hot Springs Memorial Field, the temperature increased from 84 at 2:45 a.m. to 91 at 3:05 a.m. By 7:30 a.m., the station was reporting 77 degrees.
"As the surface pressure dropped, winds gusted to 30-40 mph. This phenomenon was not isolated to only Hot Springs, in fact, several other weather station reporting sites recorded a similar event," the post said.
A graphic accompanying the Weather Service post explained that a "heat burst" occurs when, at the peak of a thunderstorm, warm, humid air is ingested into the storm. "Heavy rain tends to cool as it falls," it said. As the storm begins to weaken, hot air stops rising. Meanwhile, rain starts to fall into a dry or drying sub-cloud air mass and evaporates. "As the storm continues to weaken, cool air plunges downward, compresses and begins to heat, reaching the ground as a warm wind."