To: Roebear who wrote (50419 ) 9/4/1999 10:36:00 AM From: oilbabe Respond to of 95453
Roebear: That article seems to confirm the resurgence of La Nina this year. The following is from National Georgaphic online: During a La Ni¤a event, an abnormal cooling in the eastern Pacific produces conditions more or less the opposite of those created by El Ni¤o?nature?s way, perhaps, of rectifying the heat imbalance that El Ni¤o represents. As with El Ni¤o, the effects of La Ni¤a are most pronounced from December to March. In La Ni¤a years the easterly winds from the Americas are stronger than usual. That drives more than the normal amount of warm sea-surface water westward, in turn causing larger than normal volumes of deep, chilly water to rise to the surface and producing a ?cold tongue? that extends 3,000 miles [4,800 kilometers] along the Equator from Ecuador to Samoa. With so much warm water flowing toward Asia, the Pacific?s mighty heat engine remains firmly anchored in the west, causing heavier monsoon rains in India, higher than average precipitation in Australia, and wetter than normal conditions as far west as southern Africa. The huge air masses and cloud banks associated with the hot zone also change the path of the jet streams, which move high-altitude air from west to east across the ocean. The polar jet stream, which in an El Ni¤o year stays high in Canada, moves farther south, driving frigid air down into the U.S. Winters are colder, especially in the northwestern and upper midwestern states. The subtropical jet stream that blows across Mexico and the Gulf during El Ni¤o events weakens during La Ni¤a; consequently, far less rain falls in the Gulf and southeastern states. Drought is common in the desert Southwest. Hurricanes in the tropical Atlantic encounter no westerly wind resistance and therefore are twice as likely to strike the U.S. The 1998 La Ni¤a hurricane season was the deadliest in the past two centuries.