From viewer Susan Maddox in Big Canoe
(WXIA) -- The National Weather Service uses specific criteria to define what advisories are issued in a particular area.
A Winter Storm Watch is issued when there is a potential for heavy snow or significant ice accumulations. The advisory is usually issued at least 24-to-36 hours in advance.
A Winter Weather Advisory is issued when a low pressure system produces a combination of winter weather that presents a hazard, but does not meet the criteria for a warning.
A Winter Storm Warning is issued when a winter storm is producing, or is forecast to produce heavy snow or significant accumulations of ice.
An Ice Storm Warning is issued when freezing rain produces a significant, and possibly damaging amount of ice in a given area. The warning is generally issued when more than 1/4-inch of ice is expected.
* Ice Storm Warning issued for areas south of Atlanta
* Delta cancels 1,000 flights
* Icy conditions on local highways
* 89 counties under state of emergency