When meteorologists forecast a winter storm one of the important questions they must answer is: will there be rain, snow, sleet, or freezing rain? That's often a challenging question. Because that water freezes at 32°F (0°C), a couple of degrees change in temperature can mean an entirely different form of precipitation. For example, a temperature is 34°F (1°C) means that precipitation will fall as rain. A few degrees colder could mean a snow day!

Look at the graphs below. Decide how precipitation changes form as it falls through the air at different temperatures from the upper levels of the atmosphere to the ground.

Graph 1: The curve of the graph shows the precipitation initially falling through below freezing air temperatures high in the atmosphere. As it falls, the precipitation then passes through air that is above freezing. The precipitation falls onto the ground when the air temperature is at 0 degrees C.

Forecast the precipitation for graph 1


Graph 2: The curve of the graph shows the precipitation initially falling through below freezing air temperatures high in the atmosphere. As it falls, the precipitation then passes through air that is above freezing. As the precipitation gets lower in the atmosphere, it again goes through below-freezing temperatures. The precipitation falls onto the ground when the air temperature is just below 0 degrees C.

Forecast the precipitation for graph 2


Graph 3: The linear line of the graph shows the precipitation initially falling through below freezing air temperatures high in the atmosphere and landing on the ground at a temperature of 0 degrees C.

Forecast the precipitation for graph 3


Graph 4: The curve of the graph shows the precipitation initially falling through below freezing air temperatures high in the atmosphere. About midway to the ground, the precipitation passes through air that is above freezing. Right before it falls onto the ground, the precipitation goes through below-freezing temperatures. The precipitation falls onto the ground when the air temperature is just below 0 degrees C.

Forecast the precipitation for graph 4