When you see certain things on a skew-t, a diagram that gives meteorologists a vertical profile of the atmosphere, you know you are in trouble. Our trouble today and tonight is ice.
This is a Skew-T/Log-P diagram. This one shows, by the black lines, temperatures increasing with height. Temperatures (in celsius) increase from left to right, and height increases from bottom to top of this diagram. We can see by the black lines, that the temperature is increasing with height, while temperatures at the surface are around freezing, which is 0 degrees Celsius.
Remember, freezing rain is liquid precipitation until it comes into contact with an object that has a temperature at, or below freezing, where the liquid instantly freezes. That is what we are looking at.
While looking at the conditions at the time of the picture, we can see that the surface is below freezing. Since the rain was a liquid until it made contact, we can easily assume the temperature aloft was warmer.
Keep in mind, when there is an icy glaze, untreated roadways, sidewalks, driveways, and parking lots are very slippery. You should exercise extreme caution in these conditions.
Ray Petelin,
WSEE Storm Team Meteorologist