CHICOPEE, Mass. (WWLP) – Some areas of western Massachusetts Saturday got rain, sleet, and some snow and freezing rain.
So how do the different types of precipitation form?
Well it’s much more complicated than just the surface air temperature. You have to look at the temperature profile high up in the sky. All precipitation starts off as snow because the atmosphere is so cold. With plain rain, you have a thick slice of warm, above-freezing air that extends all the way down to the surface.
With freezing rain, it still starts as snow. Then it encounters a layer of warmer air where it melts. But with freezing rain, there is a thin layer of freezing air right at the surface. So the rain freezes upon contact with objects that are near-freezing, like your car or your sidewalk.
Sleet, starts as snow, encounters a warmer layer where it melts, and then another thicker layer of below-freezing air allowing it to partially refreeze before hitting the ground. And last but not least, snow falls when the entire column of air is below freezing.