A weather glossary will be both useful for students and teachers throughout the unit.

A

Air pressure
Air pressure is measured in hectopascals.  Regions of sinking air are called high pressure regions.  Clear skies and fair weather usually occur in these regions.  Regions of rising air are called low pressure regions.  Clouds, rain and strong winds often occur in these regions.  High and low pressure regions do not stay in the same place.  They move over the earth’s surface. 

Anemometer
Is an instrument used to measure wind speed.

B

Barometer
An instrument used to measure atmospheric pressure.

Beaufort wind scale
A number system estimating and reporting wind speeds.  It is based on the Beaufort Force or Number, which is composed of the wind speed, a descriptive term, and the visible effects upon land objects.  The scale was devised by Sir Francis Beaufort (1777-1857), hydrographer to the British Royal Navy.

Blizzard
A severe weather condition characterised by low temperatures, strong winds, falling snow and reduced visibility.

Breeze
A severe snowstorm with high winds and low visibility.

C

Calm
An atmospheric condition that lacks wind or any other air motion.

Clear
The state of the sky when no clouds are observed.

Cloud
A visible collection of minute particle matter, such as water droplets and/or ice crystals, in the air.  A cloud forms in the atmosphere as a result of condensation of water vapour.

Cold
A condition marked by a low temperature.

Condensation
The process by which water vapour undergoes a change in state from a gas to a liquid. 

Cumulonimbus clouds
Also called a thunderstorm cloud.  It is frequently accompanied by heavy showers, lightening, thunder, and sometimes hail or strong gusty winds.

D

Drizzle
Light precipitation falling in very fine drops.

E

Ecolinc
Ecolinc is a Department of Education and Early Childhood Development, Science Specialist Centre situated in Bacchus Marsh.

Ecolinc Weather Wall
Ecolinc Weather Wall displays weather data collected on site at Ecolinc.

El Nino
A warming of the East Pacific Ocean sea water temperatures off the western coast of South America that can result in changes in weather patterns in Australia and around the world.  The impacts for Australia are warmer, dryer conditions with less rainfall.

F

Fog
Visible, minute water droplets suspended in the atmosphere at or near the earth’s surface.

G

Gale wind
A strong wind.

H

Hail
Pellets of frozen rain that falls in showers from cumulonimbus clouds.

Haze
A suspension of fine dust and/or smoke particles in the air.

High pressure system
Is a whirling mass of cool, dry air that generally brings fair weather and light winds. 

Humidity
The amount of water vapour in the air.

I

Isobars
A line drawn on a weather map connecting points of equal pressure.

J

K

L

La Nina
Is an upwelling of unusually cold water to the oceans surface in the waters of the Pacific near the equator and off the west coast of South America.  This often occurs after an El Nino event and disrupts global weather patterns.  The impacts for Australia are wetter conditions.

Low pressure system
Is a whirling mass of warm, moist air that generally brings stormy weather with strong winds. 

M

Mean
An average.

Meteorology
The science that studies atmospheric phenomena, especially those that relate to weather.

Meteorologist
A person that predicts the weather and relies on weather stations, which take measurements on such things as air pressure, temperature, wind speed, wind direction, cloud cover and precipitation, to make forecasts.

Mist
A collection of microscopic water droplets suspended in the air.

N

O

Overcast
Clouds covering a large part of the sky.

P

Precipitation
Is a generic term used to describe any form of moisture that falls from the air to the ground.  This includes rain, snow, hail, sleet and drizzle. 

Prevailing wind
A wind that blows from one direction more frequently than other.

Q

R

Rain
Precipitation that falls visibly in separate drops.

Rain gauge
An instrument which measures precipitation.

Rain radar
Radio Detection and Ranging.  An instrument that measures the strength of precipitation and clouds.

Rain shadow
A region having little rainfall because it is sheltered from prevailing winds that bring rain, by a range of hills.

S

Satellite image
Images taken by a weather satellite that reveal information such as weather systems.

Saturation (related to humidity)
To treat something to the point where no more can be absorbed.  In meteorology, it is used when discussing the amount of water vapour in the air.

Sleet
A form of precipitation consisting of ice pellets, often mixed with rain and snow.

Smoke
Small particles produced by combustion that are suspended in the air.

Snow
Atmospheric water vapour frozen into ice crystals and falling in light flakes. 

T

Temperature
The degree of hotness or coldness in the environment.

Thermometer
An instrument used to measure temperature.

Thunderstorm
Produced by a cumulonimbus cloud, under severe weather conditions.

Trend
A general direction in which something is taking.

Tropical cyclone
A storm system characterised by a large low pressure centre and numerous thunderstroms that produce strong winds and heavy rain.  These form over tropical waters.

U

V

W

Weather
The state of the atmosphere at a specific time.

Wind
Horizontal movement of air.

Wind chill
The calculation of temperature that takes into account the effects of wind and temperature on the human body.

Wind speed
Is the speed of the wind.

Wind vane (also known as a weather vane)
Is a tool for measuring wind direction.  To determine wind direction, a wind vane spins and points in the direction from which the wind is coming and generally has two parts; one that is usually shaped like an arrow and turns into the wind and one end that is wider so that it catches the breeze.  The arrow will point to the direction the wind is blowing from, so if the arrow points to the east, it means the wind is coming from the east. 

X

Y

Z