Throughout 2008, 124 tropical cyclones have formed in bodies of water known as tropical cyclone basins. Of these, 83 have been named, by various weather agencies when they attained maximum sustained winds of . The strongest storm of the year was Typhoon Jangmi in the Western Pacific Ocean. The deadliest storm of the year was Cyclone Nargis, which caused devastating and castatrophic destruction in Myanmar with 138,373 fatalities. The costliest storm of the year was Hurricane Ike, which wreaked havoc thorough Cuba and Texas, with $38 billion (2008 USD) in damage. Throughout the year, 24 Category 3 tropical cyclones formed, including one Category 5 tropical cyclone in the year.
Tropical cyclones are primarily monitored by a group of ten warning centres, which have been designated as a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC) by the World Meteorological Organization. These are the United States National Hurricane Center (NHC) and Central Pacific Hurricane Center, the Japan Meteorological Agency (JMA), the India Meteorological Department (IMD), Météo-France, Indonesia's Badan Meteorologi, Klimatologi, dan Geofisika, the Australian Bureau of Meteorology (BOM), Papua New Guinea's National Weather Service, the Fiji Meteorological Service (FMS) as well as New Zealand's MetService. Other notable warning centres include the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), the United States Joint Typhoon Warning Center (JTWC), and the Brazilian Navy Hydrographic Center.
Global atmospheric and hydrological conditions
La Niña conditions often follow El Niño in the cycle known as the El Niño/Southern Oscillation (ENSO). La Niña episodes are marked by stronger-than-normal easterly trade winds and below-normal sea surface temperatures in the eastern tropical Pacific Ocean. These changes in ocean temperature and atmospheric circulation have worldwide implications for weather patterns. La Niña conditions appeared in February 2007 and strengthened in October and November. La Niña conditions often peak in January, as they appeared to do in January 2008.
This image shows the temperature anomaly for the top millimeter of the Pacific Ocean's surface—the skin temperature—on January 14, 2008, based on data from the Advanced Microwave Scanning Radiometer (AMSR-E) flying on NASA's Aqua satellite. In this image, January 14, 2008, temperatures are compared to the long-term average measured by a series of sensors that flew on NOAA Pathfinder satellites from 1985 to 1997. A strong band of blue (cool) water appears along the Equator, fanning out near North and South America. Patches of orange to red (warm) conditions appear north and south of this strong blue band. As of January 2008, the U.S. National Oceanic and Atmospheric Administration (NOAA) predicted that La Niña conditions would continue until spring, with a possible weakening in February 2008.
Cool ocean temperatures can impede cloud growth, leading to reduced rainfall from South America to Indonesia. In the continental United States, La Niña affects the jet stream, which in turn affects weather. Typical La Niña winter weather patterns include very cool, wet conditions in the Pacific Northwest, especially cold winter conditions on the Great Plains, and unusually dry conditions in the Southwest and Southeast. Because La Niña conditions can persist for years, such adverse weather conditions can continue. In short, continued La Niña conditions were expected to prolong the droughts in the American Southeast and Southwest.
Summary
North Atlantic Ocean
The 2008 Atlantic hurricane season was the most destructive Atlantic hurricane season since 2005, causing over 1,000 deaths and nearly $50 billion (2008 USD) in damage. The season ranked as the third costliest ever at the time, but has since fallen to seventh costliest. It was an above-average season, featuring sixteen named storms, eight of which became hurricanes, and five which further became major hurricanes. It officially started on June 1 and ended on November 30. However, the formation of Tropical Storm Arthur caused the season to start one day early. It was the only year on record in which a major hurricane existed in every month from July through November in the North Atlantic. Bertha became the longest-lived July tropical cyclone on record for the basin, the first of several long-lived systems during 2008.