What determines whether Q will fall as freezing rain or snow?
Our atmosphere is composed of layers of air with different temperatures. So air temperature at the earth’s surface may be different from that above. What determines whether you get freezing rain, snow or rain, is the thickness of warm and cold air over your region, as well, as the surface air temperature. For example, freezing rain is possible when warm moist air with temperatures above 0 degrees Celsius is sandwiched between two colder layers of air below 0 degrees Celsius. What happens in this case is, Q from higher, colder levels begin falling as snow. As it falls through the warmer lay in between, the snow melts into rain drops. The warm layer must be around 1500 meters thick with temperatures above 0 degrees in order for the snow to melt. The Q now reached the cold surgace temperature (in your case -7 degrees Celsius) as rain which freezes as it falls to the ground. In order for the rain to become freezing rain, this colder layer must be around 1300 meters thick. As long as the su
