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The strongest westerly winds in the middle latitudes can come in the roaring forties, between 40 and 50 degrees south latitude. The westerlies play an important role in carrying the warm, equatorial waters and winds to the western coasts of continents, especially in the southern hemisphere because of its vast oceanic expanse.
The Roaring Forties are strong westerly winds that occur in the Southern Hemisphere, generally between the latitudes of 40° and 50° south. [2] The strong eastward air currents are caused by the combination of air being displaced from the Equator towards the South Pole , Earth's rotation , and the scarcity of landmasses to serve as windbreaks ...
The term originally derives from the early fourteenth century sense of trade (in late Middle English) still often meaning "path" or "track". [2] The Portuguese recognized the importance of the trade winds (then the volta do mar, meaning in Portuguese "turn of the sea" but also "return from the sea") in navigation in both the north and south Atlantic Ocean as early as the 15th century. [3]
In its positive phase, the westerly wind belt that drives the Antarctic Circumpolar Current intensifies and contracts towards Antarctica. [9] In winter, a positive phase increases rainfall (including East coast lows) in south-eastern Australia (above Victoria) due to higher onshore flows from the Pacific Ocean, decreases rain in the south-west, and decreases snow in the alpine areas.
But the winds above the surface, where they are less disrupted by terrain, are essentially westerly. A low pressure zone at 60° latitude that moves toward the equator, or a high pressure zone at 30° latitude that moves poleward, will accelerate the Westerlies of the Ferrel cell. A strong high, moving polewards may bring westerly winds for days.
Foehn winds usually occur when the westerly wind belt moves northwards. [7]The foehn effect on the coastal plains of southeastern Australia is mostly linked with the passage of a deep low pressure system or westerly cold fronts across the Great Australian Bight and southeastern Australia that cause strong winds to reorient virtually perpendicular to some parts of the Great Dividing Range ...
Abatzoglou said the wind initially came from the west to spread the fires into the shape of an ellipsis on a map, then shifted about 90 degrees and began to push those lines to the south.
A westerly wind burst is defined by Harrison and Vecchi (1997) as sustained winds of 25 km/h (16 mph) over a period of 5–20 days. [3] However, no concrete definition has been determined, with Tziperman and Yu (2007) defining them as having winds of 14 km/h (8.7 mph) and lasting "at least a few days".