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NOAA image of USA map.December 17, 2002 — The climate of 2002 in the United States was characterized by warmer than normal temperatures and below average precipitation that led to persistent or worsening drought throughout much of the nation, according to NOAA scientists.

Working from the world’s largest statistical weather database, NOAA scientists at the National Climatic Data Center also found that 2002 is very likely to be the second warmest year on record for the globe. The return of El Niño affected hurricanes in the Atlantic and precipitation patterns in some parts of the world.

U.S. Temperatures
NOAA image of USA state temperature rankings through November 2002.The average temperature for the contiguous United States in 2002 is expected to be near 53.6 degrees F (12.0 degrees C), one of the 20 warmest years since national records began in 1895, but significantly cooler than last year, which was the 7th warmest year. The average temperature during the 1895-present record is 52.8 degrees F, with the warmest year on record occurring in 1998. (Click NOAA image for larger view of USA state temperature rankings through November 2002. Click here for high resolution image, which is a large file. Please credit “NOAA.”)

The year 2002 began with another anomalously warm winter, the fourth much warmer-than-average winter in the last five years, and the summer season was one of the warmest since the 1930s. Temperatures in Alaska were above average in all four seasons, and 2002 will approach or exceed the warmest year on record for the state.

Overall the contiguous United States temperature has risen at a rate of 1.0 degree F/Century (0.6 degrees C/Century) since 1895. Much of that increase has occurred in two periods, 1910-1940 and again from the 1970s to the present. Temperatures in Alaska have increased at a rate near 2.8 degrees F/Century (1.5 degrees C/Century) since the early 1900s, most rapidly in the past 25 to 30 years.

U.S. Precipitation, Drought and Flooding
NOAA image of significant weather across the USA in 2002. As the year began, moderate to extreme drought covered one-third* of the contiguous United States, including much of the eastern seaboard and northwestern United States. The combination of generally warmer- and drier-than-average conditions led to the total drought area growing to slightly more than 50 percent during the summer months, largely due to a rapid intensification of drought in the Southwest. This value fell to 36 percent by the end of November as precipitation from landfalling tropical systems and a more active storm track helped alleviate drought in much of the eastern part of the country. (Click NOAA image for larger view of significant weather across the USA in 2002. Click here for high resolution image, which is a large file. Please credit “NOAA.”)

The most extensive national drought coverage during the past 100 years (the period of instrumental record) occurred in July 1934 when 80 percent of the contiguous United States was in moderate to extreme drought. Although the current drought and others of the 20th century have been widespread and of lengthy duration, tree ring records indicate that the severity of these droughts was likely surpassed by other droughts, including that of the 1570s and 1580s over much of the Southwest and northern Mexico.

In the western United States where precipitation for 2002 is on pace to set record or near-record lows in many states, the lack of adequate rain and snow and the resulting low snowpack stressed water supplies and caused devastating impacts on agriculture. Severe drought in Montana that began in some places more than four years ago forced farmers to abandon more than 20 percent of the winter wheat crop for the second consecutive year, the first such occurrence since the Dust Bowl era of the 1930s. The extremely dry conditions also contributed to an extremely active wildfire season that included the largest wildfires of the past century for the states of Colorado, Arizona and Oregon.

Extremely dry conditions in the Northeast improved with four consecutive months of above-normal precipitation for the region from March through June, and abnormally dry conditions were largely absent near the end of the year. Above-average rainfall from September through November also brought significant drought relief to the Southeast, where more than four years of drought had affected much of the region from Georgia to Virginia.

In Texas, heavy rainfall alleviated drought but led to severe flooding in southern and central parts of the state in early July. Strong thunderstorms also brought widespread flooding to western Minnesota and North Dakota and resulted in hundreds of millions of dollars in damage and crop losses in June.

*This drought statistic is based on the Palmer Drought Index, a widely used measure of drought. The Palmer Drought Index uses numerical values derived from weather and climate data to classify moisture conditions throughout the contiguous United States and includes drought categories on a scale from mild to moderate, severe and extreme.

Atlantic Hurricane Season
Of the 12 named storms that formed in the Atlantic basin during 2002, four became hurricanes and two were classified as major hurricanes (category 3 or higher on the Saffir Simpson hurricane scale), slightly less than the annual average of 5-6 hurricanes and 2-3 major hurricanes. A strengthening El Niño episode in the equatorial Pacific suppressed the number of hurricanes and weakened the storms that did develop in 2002, according to the NOAA Climate Prediction Center.

With the exception of 2002 and 1997, years that were both affected by El Niño, at least three major hurricanes have developed in every season since 1995 with five or more major hurricanes occurring in three of those seasons (1995, 1996 and 1999). However no long-term trend in hurricane strength or frequency has been observed in the Atlantic Basin.

Global Events
NOAA image of world climate events in 2002. Other climate signatures typical of El Niño also emerged in countries such as Australia, India and Indonesia as the El Niño episode evolved during the year. Drought in Australia became more widespread and severe, and a new record warm winter maximum temperature for Australia occurred. (Click NOAA image for larger view of world climate events in 2002. Click here for high resolution image, which is a large file. Please credit “NOAA.”)

Other conditions common during an El Niño episode included a drier-than-average summer monsoon season in India and drier than normal conditions in Indonesia during May-October. The June-September monsoon season for India as a whole was characterized by large-scale drought with seasonal rainfall (June-September) 19 percent below normal.

In contrast, heavy rainfall in northeastern India, Nepal and Bangladesh brought severe flooding and caused approximately one thousand deaths in June. The most damaging typhoon to affect Korea since 1959, Typhoon Rusa, made landfall on the Korean Peninsula at the end of August.

In parts of central Europe heavy rains fell during the first 13 days of August, causing disastrous floods on the Elbe and Danube rivers with more than 100 lives lost and damages estimated at $30 billion.

In Africa, severe drought continued across parts of the Greater Horn of Africa, and widespread flooding occurred in Morocco during November and in parts of Madagascar during January-May as four tropical cyclones impacted the island nation.

Global Temperatures
Data collected from weather and climate stations, satellites, ships, buoys and floats indicate that the 2002 average global temperature will very likely be the second-warmest on record, slightly cooler than the record warm year of 1998. The ten warmest years have all occurred since 1987, with nine of them since 1990.

During the past century, global surface temperatures have increased at a rate near 1.0 degree F/Century (0.6 degrees C/Century), but the trend has been three times larger since 1976, with some of the largest temperature increases occurring in the high latitudes. In 2002, warmer temperatures and shifts in atmospheric circulation patterns contributed to the greatest surface melt on the Greenland Ice Sheet in the 24-year satellite record. There was also a record low level of Arctic sea ice extent in September, the lowest since satellite monitoring began in 1978, according to the National Snow and Ice Data Center.

Data collected by NOAA polar orbiting satellites and analyzed for NOAA by the University of Alabama in Huntsville and Remote Sensing Systems in Santa Rosa, Calif., indicate that temperatures centered in the middle troposphere at altitudes from 2 to 6 miles are also on pace to make 2002 the second-warmest year for the globe. The average lower troposphere temperature (surface to about 5 miles) for 2002 will also very likely be the second warmest on record.

Analysis of the satellite record that began in 1979 shows that the global average temperature in the middle troposphere has increased, but the differing analysis techniques of the two teams result in different trends. The UAH team found an increase of 0.06 degrees F/decade (0.035 degrees C/decade) while a trend of 0.21° F/decade (0.115° C/decade) was found by the RSS team. This compares to surface temperature increases approaching 0.3 degrees F/decade during the same period.

The NOAA National Environmental Satellite, Data, and Information Service (NOAA Satellites and Information) is the nation’s primary source of space-based and surface-based meteorological and climate data. NOAA Satellites and Information operates the nation's environmental satellites, which are used for weather forecasting, climate monitoring and other environmental applications such as fire detection, ozone monitoring and sea surface temperature measurements.

NOAA Satellites and Information also operates three data centers, which house global data bases in climatology, oceanography, solid earth geophysics, marine geology and geophysics, solar-terrestrial physics, and paleoclimatology.

Relevant Web Sites
NOAA Weather 2002 in Perspective

NOAA Says El Niño to Influence U.S. Weather

NOAA National Climatic Data Center

NOAA Satellite and Information Services

NOAA's Storm Watch — Get the latest severe weather information across the USA

NOAA's Drought Information Center

Media Contact:
John Leslie, NOAA National Weather Service, (301) 713-0622 or Patricia Viets, NOAA Satellite and Information Services, (301) 457-5005