XM WX Weather Features
Fronts
The Fronts feature displays the lines indicating the leading edge of an air mass that is replacing an existing air mass. This feature also displays pressure centers. Pressure centers are represented by a large red “L” for low-pressure centers or a large blue “H” for high-pressure centers. Pressure centers represent an area where pressure is measured to be either the highest or the lowest pressure relative to the surrounding area.
Cold Front
Warm Front
Stationary
Front
Occluded
Front
Dry Line
Indicates a low-pressure center. A low-pressure center is an area where the measured pressure is lowest relative to the surrounding area. Moving away from a low-pressure center in any horizontal direction results in increased pressure. Winds flow counterclockwise around low-pressure centers in North America.
Indicates a high-pressure center. Similar to a low- pressure center, a high-pressure center is an area where the measured pressure is highest relative to the surrounding area. Moving away from a high-pressure center in any horizontal direction results in decreased pressure. Winds flow clockwise around high-pressure centers in North America.