What Temperature Determines Snow Or Rain?
Basically, you cannot use a surface temperature to determine rain or snow. An analysis of the temperature profile must be done to see how temperatures will be in the atmosphere, from where precipitation is being produced all the way down to the surface. You can get rain with surface temperatures well below freezing (which makes it freezing rain) and you can get snow with surface temperatures above freezing (I have seen it snow with a surface temperature in the 40’s). I can only suppose that the system is predicting heavy rain because the surface temperature is above freezing and the temperatures in the clouds are warm enough that snow production is not expected.
