“There is a weak surface trough that is hanging over the CSRA area right now,” said Bill Murphey, the state climatologist and chief meteorologist for the Environmental Protection Division of the Georgia Department of Natural Resources.
The trough helps to promote convection or rising warm moist air to form clouds that lead to the storms.
“Basically, the atmosphere just heats up,” Murphey said. “When it gets to a certain temperature, it gets unstable.”
The rising warm air meeting the cooler air can lead to storms with a lot of lightning, he said.
“They can dump heavy rain and you can get small hail from them,” Murphey said. “And with the cold air aloft, you can get a lot of lightning. They don’t move very fast. That’s another big difference. They just sit over one area and dump a lot of rain.”
These summer storms can produce microbursts, or gusts of strong wind, but typically lack the strong upper level winds to produce tornadoes, he said.
A subtropical high pressure ridge in the Atlantic, sometimes called a Bermuda High or Bermuda ridge, is expected to extend back west over the area this weekend and bring drier weather, Murphey said.
Although there is still a chance for afternoon storms, they will likely be fewer and widespread, he said.
It appears the state has already entered “typical summertime patterns,” Murphey said. “You think high in the low 90s, isolated afternoon thunderstorms, that is typical Georgia summertime conditions.”