Air Pressure TeamHome | Fast Facts | Picture Help | Maps and Graphs
Fast Facts for the Air Pressure Team
- The readings are in millibars (mb). The average sea-level pressure is 1013.25 mb.
- Isobars are lines connecting places of equal air pressure.
- Air pressure changes help predict local weather. Rising air pressure usually means fair weather. Falling air pressure generally means stormy weather.
- On a weather map "H" shows the relative high pressure ("happy weather") and "L" shows the relative low pressure ("lousy weather"). These pressure readings are relative. That means there is no certain number that divides high from low.
- Low pressure surface winds, viewed from above in the Northern Hemisphere, blow counterclockwise and inward.
- High pressure surface winds, viewed from above in the Northern Hemisphere, blow clockwise and outward.