Weather fronts

Surface weather analysis

A surface weather analysis is a special type of weather map which provides a top view of weather elements over a geographical area at a specified time based on information from ground-based weather stations. Weather maps are created by detecting, plotting and tracing the values of relevant quantities such as sea-level pressure, temperature, and cloud cover onto a geographical map to help find synoptic scale features such as weather fronts. Surface weather analyses have special symbols which show frontal systems, cloud cover, precipitation, or other important information. For example, an H may represent a high pressure area, implying fair or clear weather. An L on the other hand may represent low pressure, which frequently accompanies precipitation and storms. Low pressure also creates surface winds deriving from high pressure zones and vice versa. Various symbols are used not just for frontal zones and other surface boundaries on weather maps, but also to depict the present weather at various locations on the weather map. In addition, areas of precipitation help determine the frontal type and location.