High pressure often represents stable air, while low pressure can signify instability. On a cold, sunny day there will be a significantly higher atmospheric pressure than when a big storm is ...

Pressure is measured in millibars. Standard pressure at sea level is 1013 millibars, but large areas of either high or low pressure can occur. Areas of high and low pressure are caused by rising ...

Warm air then rapidly rises, creating low pressure. This leads to condensation and the development of large towering clouds and torrential rain. As warm moist air moves in to replace the rising ...

The record-strong low-pressure system is developing offshore of Oregon and Washington, causing low air pressure that is ... state as winds gusted as high as 101 mph nearby. The National Weather ...