From the National Weather Service:
...A strong thunderstorm will impact portions of northwestern DeKalb, southwestern Gwinnett and northeastern Fulton Counties through 745 PM EDT... At 714 PM EDT, a strong thunderstorm was over Sandy Springs, or 9 miles east of Marietta, moving east at 25 mph. HAZARD...40 to 50 mph wind, up to penny sized hail, frequent cloud