H
Clumps of layered ice that form in updraughts (rising air) within thunderstorms.
For terms describing hail in forecasts see Intensity of hail, Giant hail and Large hail.
Extremely small dry particles suspended in the air that reduce horizontal visibility, like light mist. Haze is distinguished from mist by humidity. If the humidity is less than 90%, it's haze.
Three or more days in a row when both daytime and night-time temperatures are unusually high. Temperatures must be high compared to the local long-term climate and the recent past.
Atmospheric circulations of high air pressure that rotate anticlockwise in the southern hemisphere. High pressure systems generally bring lighter winds and fine, settled conditions.
The ocean areas for which the Bureau provides forecasts and warnings. These are part of the Global Maritime Distress Safety System.
Highest tide level predicted under average meteorological conditions and any possible combination of astronomical conditions. Often referred to as HAT.
Measure of how much water vapour is in the air.
Large-scale severe storm with violent winds. This term is used in the USA. In Australia, these storms are called tropical cyclones and in Asia, typhoons.
Area of science concerned with the distribution, properties and movement of Earth's water.
Study of atmospheric processes that affect water resources. This includes the atmospheric and land phases of the hydrological cycle and the relationships involved.