Habagat Southwest Amihan Northeast: What Is Monsoon Weather?
A "monsoon" is a weather pattern; a monsoon has a different name in each country that it affects. In the Philippines, the Summer Monsoon (West or southwest) is called the Habagat (ha-bag-at) and the Winter Monsoon (North or northeast) is called the Amihan (a-me-han). The word 'monsoon' is believed to originate from the Arabic word mawsim (season), via the Portuguese and then Dutch monsun.
A "monsoon" is a consistent wind pattern generated by a large weather system, that lasts for a period of months and affects a large area of the planet.
Summer Southwest Monsoon - Habagat
Summer Monsoon weather is characterized by a strong, generally West or southwest breeze that is responsible for bringing significant rainfall to the Asian subcontinent and to South and East Asia. The significant southwest monsoon rainfall is a by-product of air passing over large areas of warm equatorial ocean, stimulating increased levels of evaporation from the ocean’s surface; the southwest monsoon air, now laden with water vapour, cools as it moves north and as it rises over land; at some point the air is no longer able retain its moisture and precipitates copious volumes to irrigate rice fields and drench rainforests, sometimes causing severe flooding below hillsides that have been foolishly stripped of forest cover by Man. The Summer Monsoon (West or southwest) is the predominant weather pattern from late April through to early October each year, throughout most Asian tropical destinations.
Winter Northeast Monsoon - Amihan
Winter Monsoon weather features a generally less strong, East or northeast breeze that is cool and dry (compared to the Summer Monsoon weather) with prolonged periods of successive cloudless days. The Winter Monsoon (North or northeast) features cool and dry air that originates in a vast anticyclone - a weather system with a high barometric pressure - which forms over Siberia, Mongolia and northern China during each northern winter. The Winter Monsoon air from the anticyclone pushes outward in a clockwise motion from its centre and competes with the Summer Monsoon over a period of a week or two, usually starting in late September and early October, before finally dominating the weather with a cooler and drier northeast monsoon, in most Asian tropical and sub-tropical destinations, through to the following April.
There is no specific weather pattern equivalent to a monsoon season in southern latitudes because there is no continent large enough to create the conditions similar to those that drive the alternate Winter Monsoon, as in the North. It could be said that the southern hemisphere is perpetually in varying degrees of Summer Monsoon condition; Brazil and parts of equatorial Africa occasionally experience some weather patterns that show some seasonal differences.
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