With the end of 2004, it will rank among the top 10 wettest years on record for the contiguous United States and is expected to be warmer than average, according to scientists at the NOAA Climatic Data Center in Asheville, N.C. The findings are based on preliminary data and historical records dating back to 1895. While parts of the West remained in drought, rainfall was above average in 33 states, especially in the South and East, partly due to the effects of tropical storms and hurricanes, which impacted 20 states.
A Variable Year for Temperature in the U.S.
NOAA scientists report that the average temperature for the contiguous United States for 2004 (based on preliminary data) will likely be approximately 53.5 degrees F (11.9 degrees C), which is 0.7 degrees F (0.4 degrees C) above the 1895-2003 mean, and the 24th warmest year on record. Based on data through the end of November, the mean annual temperature in two states (Washington and Oregon) is expected to be much above average, with 30 states being above average, 16 contiguous states near average and no state below the long-term mean.
Alaska's annual temperature is expected to be approximately 1.8 degrees F above the 1971-2000 average for 2004, one of the five warmest years for the state, since reliable records began in 1918. Alaska had a record warm summer with a statewide temperature of 4.6 degrees F (2.6 degrees C) above the 1971-2000 mean. May, June, July and August were all record breaking for the state. Much of the West Coast also had record or near record temperatures for the summer of 2004. In contrast, much of the remainder of the contiguous U.S. was relatively cool during June-August, including several cities in the Upper Midwest that had afternoon high temperatures in the low 50s during the middle of August.
Spring temperatures across the U.S. were above average in all states, except Florida, which was near normal for the season. Fall was warm across much of the mid-section of the country, but the West remained near average. Winter began relatively warm in November and early December for states from the Upper Midwest to the East Coast.
Hurricanes in South and East
A major feature of the climate in the U.S. in 2004 was the number of landfalling tropical systems. Nine systems affected the U.S. including six hurricanes, three of which were classified as major on the Saffir-Simpson Scale of hurricane intensity. Four of the six hurricanes affected Florida, making it the only state since 1886 to sustain the impact of four hurricanes in one season (Texas also had four hurricanes in 1886). Hurricane Charley in August was the strongest hurricane (category 4 at landfall) to strike the U.S. since Andrew in 1992 and caused an estimated $14 billion in damage. Hurricanes Frances, Ivan and Jeanne quickly followed Charley in September.
Hurricane Gaston also impacted the U.S. in August making landfall in South Carolina. In total, the hurricane season cost the U.S. an estimated $42 billion, the most costly season on record. That record has been calculated back to 1900. While there was extensive wind damage in Florida and other coastal locations, flooding was the major impact further inland. Frances impacted the Southeast and southern Appalachians after a wetter-than-average summer, causing millions of dollars in flood damage to the region. Shortly thereafter Ivan traveled a similar path through the mountains and led to widespread flooding, loss of power and landslides.
Drought and Snowpack
In contrast to the excessive rainfall in the East, much of the West began the year with a long-term rainfall deficit. A four-to-five-year drought in parts of the West intensified during the first half of 2004 as precipitation remained below average. Drier-than-average summer conditions coupled with warmer than normal temperatures in the West exacerbated the drought conditions still further during June-August. Short-term drought relief occurred in the fall as two large storms impacted the West during October. The first major snowfall of the season was associated with these storms for the Sierra Nevada. As of early December, snowpack is above average in Utah, Arizona and Nevada but significantly below average throughout much of the Northwest as well as the eastern slope of the Rockies. Near year's end, moderate to extreme drought continued to affect large parts of the West, including Montana, Idaho, Washington, Oregon, Wyoming, California, Arizona and Colorado.
Although the wildfire season got an early start in the western U.S., and record warm temperatures combined with less-than-average precipitation raised fire danger across the West through the summer, the season concluded as below average for the contiguous U.S. However, a record number of acres were burned in Alaska in 2004. Alaska and the adjacent Yukon Territory of Canada saw a rapid increase in fire activity in June, which was sustained through August consuming more than 6.6 million acres in Alaska. In Fairbanks, on 42 of the 92 days of summer, visibility was reduced from smoke associated with the wildfires. This compares to the previous record of 19 days in 1977.
The average global temperature anomaly for combined land and ocean surfaces from January-December 2004 (based on preliminary data) is expected to be 0.55 degrees F (0.31 degrees C) above the 1880-2003 long-term mean, making 2004 the 4th warmest year since 1880 (the beginning of reliable instrumental records). Averaged over the year, land surface temperatures were anomalously warm throughout western North America, southern and western Asia and Europe. Boreal fall (September-November) as well as November were warmest on record for combined land and ocean surfaces.
Other notable climate events and anomalies across the world in 2004 include an active tropical season in the Northwest Pacific with Japan sustaining ten tropical storm landfalls, exceeding the previous record of six; below normal monsoon rainfall for India, especially in the Northwest part of the country; flooding in Northeastern India from monsoon rains in June-October; a rare hurricane in the South Atlantic in March; and an extensive and severe heat wave in Australia during February.
Sea surface temperatures in much of the central and east-central equatorial Pacific increased during the latter half of 2004 as weak El Niño conditions developed. Though global impacts have been slow to develop, the NOAA Climate Prediction Center expects the current El Niño to persist through early 2005, bringing drier-than-average conditions to Indonesia, northern Australia and southeastern Africa.
The National Climatic Data Center is part of the NOAA Satellites and Information Service, America's primary source of space-based oceanographic, meteorological and climate data. The NOAA Satellites and Information Service operates the nation's environmental satellites, which are used for ocean and weather observation and forecasting, climate monitoring, and other environmental applications. Some of the oceanographic applications include sea surface temperature for hurricane and weather forecasting and sea surface heights for El Niño prediction.
NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation’s coastal and marine resources. NOAA is part of the U.S. Department of Commerce.
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