Weather Whys, July 16, 2015

Courtesy Texas A&M

Dry Lines
Q: You often hear the weatherman talk about a “dry line.” What is it?

A: Simply put, a dry line is very much like a cold front, says Brent McRoberts of Texas A&M University. “It’s sort of a boundary between very humid air and air that is dry,” McRoberts explains. “The difference between a cold front and a dry line is that the temperature on either side of a dry line doesn’t vary much, as opposed to a cold front, where the temperatures can vary a great deal. The advances of dry lines can adversely affect the weather in your area as they pass through.”

Q: Does a dry line mean rain is coming?

A: Very often, that is the case, McRoberts adds. “Clouds often form along dry lines during the afternoon and these can grow into thunderstorms,” he points out. “Dry lines typically form in the Midwest and the Great Plains states and these almost always move slowly from west to east, usually in the spring and summer months. A dry line will move eastward during the afternoon, retreat at night and often reform again the next day, and these often produce some heavy thunderstorms as they develop, especially just to the east of the dry line.”