Glossary

The weather map shows a stationary arctic front (red line/semi-circles and blue line/triangles) draped along the Alaskan Panhandle, B.C.’s Coast Mountains, and through the Southern Interior. A low pressure system approaches Vancouver Island with its warm front (red line and semicircles), cold front (blue line and triangles), and TROWAL (blue dashed line with red hooks).

A weather front is the interface between two air masses with differing characteristics such as the border between a cold, dry air mass, and a warmer, wetter one. They are named for their abrupt transitions in temperature (e.g. warm front, cold front), but significant changes in other weather elements such as moisture content, wind speed and direction, and cloud clover also tend to occur. The interface itself is not a vertical wall, rather it’s a sloped surface tilting toward the cold air.

Weather Front