WRAL WeatherCenter Blog

Has there ever been a case where there has been a low pressure at the ground and a high pressure right above it? And if this ever occured what do you think would happen?

Posted February 18, 2007 10:45 a.m. EST

MIKE MOSS SAYS:     Sammy,    This does occur from time to time, and in fact is not quite as unusual a situation as you might think. Even so, in terms of well-defined and reasonably strong centers of high or low pressure, usually they are offset somewhat from one another in typical day to day mid-latitude weather. The situation is somewhat different for tropical systems. It is not unusual for some of the most rapidly intensifying hurricanes, for example, to consist of a very intense low pressure center at the surface, almost directly beneath a strong high pressure center above. This sets up a favorable "exhaust system" for the hurricane, in which air is rapidly spiraling in toward the center in a counterclockwise manner (in the the northern hemisphere) near the surface, as is typical of a low, while at an altitude of 40-60,000 feet or so air is spiraling outward in a clockwise manner somewhat more slowly (as it is spread over a deeper layer) away from a relative center of high pressure.