Download Common Weather Map Symbols

Integrated Science
Chapter 20 – The Atmosphere
Common Weather Map Symbols
Symbol
Name
Definition
Cloudy weather and precipitation result as the low-pressure area
approaches. Low-pressure systems have different intensities with some
Low Pressure Area
producing a gentle rain while others produce hurricane force winds and a
massive deluge.
A high-pressure area usually means your region has several partly to
mostly sunny days in store with little or no precipitation. Air tends to sink
High Pressure Area
near high-pressure centers, which inhibits precipitation and cloud
formation.
Warm Front
A warm front is the boundary between warm and cool, or cold, air when
the warm air is replacing the cold air. Warm fronts often bring days of
inclement weather.
Cold Front
A cold front is the boundary between warm and cool air when the cool air
is advancing to replace the warm air. It locates the warm-cold boundary at
the Earth's surface. The air mass behind the cold front is not always frigid,
especially during summer.
Occluded Front
Often, in the later stages of a storm's life cycle, a frontal occlusion occurs.
This occurs when the air in the warm sector of the storm is lifted off the
ground. Two types of occluded fronts exist. The first is a cold occlusion,
which occurs when the air behind the front is colder than the air ahead of
the front. In this situation, the coldest air undercuts the cool air ahead of
the front and the occluded front acts very similar to a cold front. The
second type is a warm occlusion, which occurs when the air behind the
front is warmer than the air ahead of the front. In this situation, the cool air
is lighter than the coldest air ahead of the front. As a result, the cool air
rises up and over the coldest air at the surface and the occluded front acts
very similar to a warm front.
Stationary Front
A cold front is the boundary between cool and warm air when the cool air
is replacing the warm air. A warm front is the boundary when the warm air
is winning the battle. When the pushing is a standoff, the boundary is
known as a stationary front. Stationary fronts often bring several days of
cloudy, wet weather that can last a week or more.
Trough
A trough is an elongated area of low atmospheric pressure that can occur
both at the surface of the Earth and at higher altitudes. Upper-level
troughs influence many surface weather features, including the formation
and movement of surface low-pressure areas and the locations of clouds
and precipitation.