Appendix D:glossary Of Weather Terms - Raymarine E120W Reference Manual

Appendix D

Appendix D:Glossary of weather terms

Note: For types of warnings, watches and advisories, please refer to the NOAA
website at www.nws.noaa.gov/glossary.
Term
Cold front
Cyclone
Depression
Dry line
Forecast
Front
High
High Pressure
Hurricane
Definition
The boundary between two different air masses where cold air
pushes warm air out of the way and brings colder weather.
A large area of low atmospheric pressure, characterized by
inward-spiralling winds. A "low" - also called a "depression".
Also the name used for a hurricane in the Indian Ocean and West-
ern Pacific.
An area of low pressure. Also called a cyclone.
A region where there is a strong gradient in dew point temperatures.
It is often found in a region where strong thunderstorms develop.
Something that tells us what the weather is probably going to be
like.
The boundary between two masses of air with different tempera-
tures (i.e.: a mass of cold air and a mass of warm air).
Also known as an 'anticyclone' - an area of high air pressure with a
system of winds rotating outwards. This usually means dry
weather. It is the opposite of a 'low'.
A mass of air that presses down strongly on the surface of the
Earth because it is being cooled and is therefore more dense.
A violent, spiralling storm that forms over the Atlantic Ocean, with
winds over 120 kph. Such storms usually have a lifespan of several
days. Also known as a typhoon or tropical cyclone. There are 5 levels
of hurricane:
Category 1
Winds 74-95 mph (64-82 kt or 119-153 km/hr). Storm surge
generally 4-5 ft above normal. No real damage to building struc-
tures. Damage primarily to unanchored mobile homes, shrub-
bery, and trees. Some damage to poorly constructed signs. Also,
some coastal road flooding and minor pier damage.
261