Heavy to excessive rainfall may lead to flooding Wednesday over southwest Pennsylvania into northern West Virginia, and western Maryland. Flood Watches have been issued. An extended period of hot weather will continue for parts of coastal southern California including Los Angeles through Thursday. Heat Advisories remain in effect. Read More >
STATION PRESSURE: This is the pressure that is observed at a specific elevation and is the true barometric pressure of a location. It is the pressure exerted by the atmosphere at a point as a result of gravity acting upon the "column" of air that lies directly above the point. Consequently, higher elevations above sea level experience lower pressure since there is less atmosphere on which gravity can act. Put another way, the weight of the atmosphere decreases as one increases in elevation. Consequently then, in general, for every thousand feet of elevation gain, the pressure drops about 1 inch of mercury. For example, locations near 5000 feet (about 1500 meters) above mean sea level normally have pressures on the order of 24 inches of mercury. |