A very complex forecast continues through the evening hours as a surface low continues to deepen off the GC region. A positive trough will deepen helping to promote lift at the surface and dragging in cooler air from the north. Precipitation will continue to move into the area from the SW to the NE, with far NW GA seeing lessening coverage.
The transition zone/rain-snow line has been meandering from Franklin through metro Atlanta to Gainesville. Along and northwest of this line mostly snow has been observed with rain south of this line. Depending on precipitation rates, we will see some bursts of snow along this transition line. When precipitation rates lessen, it will convert back over to rain/sleet. We will see this trend continue through the early evening.
The rain-snow line should gradually move SE later this evening. As the surface low lifts off the GA/Carolina coast through the overnight, we will see a trough of warm air aloft set up across north GA. With cold air continuing to move into the region from the mid and low levels, we think this will enable those in the Warning and Advisory to see mainly light snow (pockets of heavier bands possible), especially after midnight. Additional snowfall through the overnight for the warned area is 1 to 2 inches with locally higher amounts. Those in the advisory may see an additional snowfall totals of 1 inch, with locally higher amounts. As the low lifts out by early Saturday morning, this will erode the band of light snow.
Another topic of concern is black ice overnight. With precipitation continuing to fall and temperatures dropping to below freezing across north and portions of central GA, residual water on the roadways may freeze as roadway temperatures also fall to near/below freezing. Temperatures will climb above freezing by mid morning with the Warning/Advisories expiring by 10AM. We will continue to monitor the surface low and tweak snowfall amounts in the next several hours. Again, a lot if dependent upon heavier precipitation amounts, which is very localized.