They are issued by Regional Forecasting Centres in each capital city several times daily and monitored continuously for changes which may occur. Routine High Seas Forecasts are issued twice daily by the Regional Forecasting Centres in Perth, Darwin, Brisbane and Melbourne for the areas beyond the coastal waters surrounding Australia. Warnings for Coastal Waters are issued whenever strong winds, gales, storm or hurricane-force winds are expected. Warnings to Shipping on the High Seas are issued whenever gale, storm or hurricane-force winds are expected. For example 25.4 South is the latitude of twenty five decimal four degrees south, NOT twenty five degrees four minutes south.
Winds flow in order to more evenly distribute heat between the equator and polar regions.
Wind direction and speed are determined by the patterns of highs, lows and fronts seen on weather maps and by local effects such as sea-breezes and thunderstorm downdrafts. Stronger wind speeds are associated with tropical cyclones, deep lows and cold fronts. Definitions and Terminology Wind speed mentioned in forecasts and coastal observations refers to the average speed over a 10-minute period at a height of 10 metres above the surface. It is given in knots. Gusts may be up to 40 per cent stronger than the average speed.