Filter
Top Products
14
Glossary of weather terms
Absolute Humidity- The density of water vapor. It is the mass of the water vapor
divided by the volume that it occupies.
Advisory- Advisories are issued for weather situations that cause significant
inconveniences but do not meet warning criteria and, if caution is not exercised, could
lead to life-threatening situations. Advisories are issued for significant events that are
occurring, are imminent, or have a very high probability of occurrence.
Air Pressure- (atmospheric pressure) air pressure is the force exerted on a surface by
the weight of the air above it. The internationally recognized unit for measuring this
pressure is the kilopascal.
Atmospheric Pressure- (also called air pressure or barometric pressure) The pressure
asserted by the mass of the column of air directly above any specific point.
Barometric pressure- The actual pressure value indicated by a pressure sensor.
Cold Front- A narrow transition zone separating advancing colder air from retreating
warmer air. The air behind a cold front is cooler and typically drier than the air it is
replacing.
Coordinated Universal Time (UTC) - The time in the zero degree meridian time zone.
Cyclone- An area of low pressure around which winds blow counterclockwise in the
Northern Hemisphere. Also the term used for a hurricane in the Indian Ocean and in the
Western Pacific Ocean.
Depression- a region of low atmospheric pressure that is usually accompanied by low
clouds and precipitation.
Doppler Radar- A type of weather radar that determines whether atmospheric motion is
toward or away from the radar. It determines the intensity of rainfall and uses the
Doppler Effect to measure the velocity of droplets in the atmosphere.
Extended Outlook- a basic forecast of general weather conditions three to five days in
the future.
Forecast- A forecast provides a description of the most significant weather conditions
expected during the current and following days. The exact content depends upon the
intended user, such as the Public or Marine forecast audiences.
Front- The boundary or transition zone between two different air masses. The basic
frontal types are cold fronts, warm fronts and occluded fronts.