Consider this forecast surface weather map from the National Weather Service. The grey lines are isobars, drawn every 4 mb. Five points labeled A, B, C, D and E are shown. Each point is on an isobar, so it is easy to determine the sea-level pressure at each point. The table below gives the elevation (in meters) of each point that is not at sea level:
B: 25 m below sea level (this is Death Valley)
C: 1600 m (Denver, approximately)
D: 180 m (note that the Great Lakes are NOT at sea level)
E: 370 m (near State College)
