Rich tropical moisture surged into the state on August 18, 2013 as a wedge front/warm front retreated northward. Deep layer shear was sufficient for rotation to produce supercells. One of these supercells interacted with this boundary and produced a strong EF-1 tornado in Heard County.
Heard County Tornado
Max wind speed: 105 MPH
Path length: 0.4 miles
Path width: 15 yards
Start time: 7:41 PM EDT (August 18, 2013)
End time: 7:42 PM EDT (August 18, 2013)
Begin location: 2 WNW Ephesus
End location: 2 WNW Ephesus
Survey Summary: A National Weather Service survey team determined that a tornado touched down just inside the Georgia-Alabama line in Heard County. A mobile home sustained roof damage and its porch was destroyed as the tornado tracked northeastward, paralleling Upper Caldwell Road. The most significant damage was as the tornado crossed upper Caldwell Road, snapping dozens of trees. The tornado left a path around 0.4 miles in length. Numerous trees were snapped in its path.
So how rare are August tornadoes? Typically the number of tornadoes for the month of August in north and central Georgia is low (see the chart below) - the exception to this though is during tropical cyclones as was evidenced by Katrina and Fay.