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Breeze blowing from the sea towards land, due to the relative warmth of the land.
Water temperature close to the surface of the sea. It's usually measured 1–20 m below the sea surface.
See Wind waves.
In Australia, the seasons are:
- Spring – September, October, November
- Summer – December, January, February (the hottest months)
- Autumn – March, April, May
- Winter – June, July, August (the coldest months)
While some people and countries use the equinoxes and solstices to define the start of each season, it's a better fit to Australia's temperatures to use 1 March, 1 June, 1 September and 1 December. Defining each season as a set of three whole calendar months is also useful for presenting climate-based statistics.
Height and direction of the swell with the second-highest energy.
Relating to earthquakes.
Weather with the potential to affect safety and wellbeing or cause damage to property and infrastructure.
Rain that usually begins and ends suddenly. Showers are relatively short-lived but may last half an hour – often, but not always, separated by blue sky. For terms describing showers in forecasts see:
Combined height of the sea and the swell that mariners experience on open waters. Refers to the average wave height of the highest third of the waves.
Also known as combined sea and swell, or total wave height.
Understanding what's going on in the environment – what it means now and in future for a particular task. Often used in relation to emergency management.
A mixture of rain and snow, or falling snow that is melting into rain.
Fog or haze thickened by smoke or other forms of atmospheric pollution. Can be hazardous to health.
Precipitation of ice crystals, most of which are branched (sometimes star-shaped).
Snow that falls for a short period, usually starting and ending suddenly. Typically, it falls from clouds formed by convection.
The water in the spaces between soil particles.
If all the spaces are occupied by air, the soil is completely dry. If they're all filled with water, the soil is saturated.
The time when the sun is at its furthest from the equator and the tilt in the Earth's axis lines up most with the direction of the sun. This means there is the greatest difference between daylight and night-time hours. These times mark the longest (around 22 December) and shortest (around 21 June) days in the southern hemisphere. They're known as the summer and winter solstices.
Calculated from the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin. It's used to gauge the strength of El Niño and La Niña events and their potential effect on the Australian region.
One of the 4 seasons of the year. In the southern hemisphere it's September, October and November.
A sudden strong wind or storm that is usually intense but short-lived.
Extended narrow region (or line) of gusty winds. Often these come with thunderstorms and rain, but a squall line can also happen when skies are clear. It's generally part of a cold front or thunderstorm environment.
See Thunderstorm.
Abnormal rise in sea level above the normal tide levels. These powerful ocean movements are caused by strong winds piling water up against the coast as a cyclone approaches.
Tide that combines storm surge with normal tide levels.
Cloud that forms in a flattish layer rather than developing height.
Cloud that forms in the lower levels of the atmosphere in a relatively flat layer, with some taller, more clumpy areas. It can produce drizzle.
Low cloud forming a uniform layer.
Flow of water in streams, rivers and other channels. Also called 'flow'.
Wind blowing at speeds of 40–50 km/h.
An area where 2 tectonic plates meet and move towards each other. One slides underneath the other and moves down into the Earth. The resulting undersea earthquakes are the main cause of tsunamis.
One of the 4 seasons of the year. In the southern hemisphere it's the 3 hottest months – December, January and February.
Times of day when sun protection is recommended (when the UV index is 3 and above).
Little chance of the sun being hidden by cloud.
Cloud expected to cover up to 15% of the sky for most the day.
A day can be called sunny though more than half the sky is covered in cirrus cloud. Cirrus clouds are often thin and wispy, allowing enough sunlight through to produce shadows.
Persistent, single, intense, rotating updraught and downdraught coexisting in a thunderstorm. It can bring violent winds (sometimes tornadoes), heavy rain and hail.
When the temperature of a liquid falls below its freezing point, without it becoming a solid.
Wind speed and direction measured at 10 m above the Earth's surface. In the marine environment, surface wind generates waves locally. Strong surface winds that come with intense storms can cause large swell waves.
See Peak wave period.
Waves which have travelled from the area where they were caused (for example, by storm activity and wind). They may travel thousands of kilometres from their origin before dying away. There can be swell waves even if the wind is calm and there are no sea waves.
Chart showing lines of equal pressure (isobars), corrected to mean sea level, over a broad area (for example, Australia). They're based on the observations taken every 3 hours by weather observers and automatic weather stations. Also called weather maps.
Used to describe weather features in the lower atmosphere that range in size from several hundred to several thousand kilometres across. For example, it's often used about high and low pressure systems over mid-latitude regions.