ASK THE METEOROLOGIST
“Why does the precipitation change?”
All precipitation falls as snow from the high very cold elevations where the clouds form and the precipitation we see at the surface all has to do with the atmospheric temperatures below those clouds. If the air is below freezing down to the surface, the precipitation remains as snow as it falls down to the ground. If there is a warm layer sandwiched between a cold layer aloft and a cold layer at the surface the snow will melt and turn to mostly rain then falling through a cold layer will partially re-freeze creating sleet, that painful rain feeling! If that mid-layer warmer layer reaches to just above the surface the snow will turn to rain then re-freeze on the surface, which is called freezing rain. This can be very dangerous by creating icy roads and ice accumulations on power lines and trees which can cause them to break. When the warm layer reaches all the way to the surface then the snow melts to rain and falls to the ground as rain.