With temperatures nearing triple digits Friday, severe thunderstorms could pop up before the weather turns cooler for the weekend.
Macon is expected to reach the upper 90s Friday afternoon — with a heat index of about 103 degrees — before temperatures drop into the mid-80s Saturday and Sunday.
Georgia climatologist Bill Murphey said the Southeastern cool-down is coming as a strong ridge is building out west that’s bringing a heat warning for Phoenix, Arizona, where temperatures up to 120 degrees are expected.
“I don’t want to see them bake, but it gives us a chance for some cooler air here,” Murphey said of the weather pattern.
The National Weather Service warns that the greatest threat for strong to severe storms Friday will be south of Interstate 20.
As summer officially begins Monday, at 6:34 p.m., temperatures rebound toward seasonal norms near 90 degrees.
“El Niño is diminishing, but we are now on La Niña watch,” Murphey said of patterns that influence U.S. weather.
If La Niña develops as expected by late summer and early fall, Murphey expects drier conditions across the Southeast, but the Atlantic hurricane season could be more active than in recent years. La Niña means cooler-than-normal sea surface temperatures in the central and eastern Pacific Ocean, near the equator off the west coast of South America.
Through August, the National Oceanic and Atmospheric Administration’s Climate Prediction Center expects Georgia to have an equal chance of having normal rainfall as it does above normal or below normal precipitation.
The same 90-day outlook shows a slight chance of above normal temperatures.
The climate center also forecasts a 70 percent chance that La Niña will be present during peak hurricane months of August through October, which could mean more storms.
Gerry Bell, the center’s lead seasonal hurricane forecaster, said the uncertainty of the pattern makes predictions difficult.
NOAA expects a 70 percent likelihood of 10 to 16 named storms, with four to eight hurricanes, and up to four being major storms with winds of 111 mph or higher.
Forecasters are leaning toward a 45 percent chance of a near-normal season, but say there is about a one-in-three chance of above normal activity.
"However, a near-normal prediction for this season suggests we could see more hurricane activity than we’ve seen in the last three years, which were below normal,” Bell said in this year’s hurricane outlook for June 1 to Nov. 30.
Murphey points out that Georgia is overdue for a tropical storm.
“It only takes one land-falling hurricane to make a big impact,” he said.