Winter 2002-03 was a season of stark contrasts in the United States, with colder-than-normal temperatures and periods of heavy snowfall prevailing in the East, while unusual warmth and persistent drought covered most of the West. For the globe, the average surface temperature was the 6th warmest on record during the December-February period, according to the Commerce Department’s National Oceanic and Atmospheric Administration (NOAA).

Scientists from the NOAA National Climatic Data Center (NCDC) in Asheville, N.C., today said, based on preliminary data, the average temperature for the contiguous United States during meteorological winter (December-February) was 34.0° F (1.1° C), which was 1.0° F above the 1895-2002 mean, but well below the record warm winter of 1999-2000, when the average temperature was 37.0° F (2.8° C). Four of the previous five winters were much warmer than average.

Twenty seven states in the eastern half of the United States experienced significantly colder-than-average weather. The below-average temperatures in the East contrasted sharply with the winter of 2001-2002, particularly in the Northeast, which had its warmest winter season on record last year. The average temperature was 10.0° F lower this winter in that region. Although temperatures were much lower than in most winters of the past couple of decades, few record cold temperatures were established and no state had a much-below-average temperature (lowest 10 percent) for the season.

Conversely, record warm temperatures were prevalent in the western United States in mid-winter, and two states (Nevada and Utah) had their warmest January on record.

For the winter season as a whole, temperatures averaged above the long-term mean from the West Coast into the Upper Midwest and Alaska. Winter in Alaska was the second warmest on record for the state, 10.1° F (5.6° C) above average and slightly cooler than the record warm winter of 2000-2001. A lack of snow and unsafe ice conditions forced organizers to move the start of the Iditarod Sled Dog race about 300 miles north from Anchorage to Fairbanks. Ground transportation on normally well frozen ice-roads was also complicated due to thinner ice on typically well traveled winter routes. Alaska winter temperatures during the past 25 years have averaged approximately 4° F (2.2° C) warmer than in the preceding 50 years.

Drought persisted in many of the same areas in the West that have experienced drought for the past three to five years. At the end of the winter season, 68 percent of the West was in moderate-to-extreme drought, based on the Palmer Drought Index.* Much-wetter-than-average conditions will be needed to end long-term drought by summer’s end in many areas. (The most widespread drought on record occurred in July 1934, when 97 percent of the West was in moderate to extreme drought.) After an extremely dry January from Colorado and New Mexico to California, precipitation amounts were generally higher in February, most notably in the Southwest. But snow pack levels at the end of the season were less than 70 percent of average in much of the West, and statewide reservoir storage was below average in every western state.

Wildfire Concerns

The low snow pack and reservoir levels are prompting concerns that spring and summer water availability may be even lower this year than in 2002, while also creating the potential for another active wildfire season. More than 7 million acres were consumed by wildfire across the U.S. in 2002, most of it in the West. Farming and ranching also continued to be impacted. In Wyoming only 24 percent of the winter wheat crop was in good condition at the beginning of March, according to the Wyoming Agricultural Statistics Service. Many ranchers in the West were also forced to sell livestock this winter because of the added expense and difficulty in obtaining feed.

Abnormally dry conditions spread east into the Upper Midwest, where the winter season was the second driest on record in Wisconsin, Iowa and Minnesota. Michigan had its driest winter since statewide records began in 1895, and by the end of February, severe drought covered much of the state.

Precipitation for the season was also significantly less than average from Kansas to North Dakota and in Illinois, Ohio, Vermont, New Hampshire and Maine. Areas to the east and south that experienced significantly wetter- and snowier-than-average conditions. Record or near record snow fell from northern Virginia to Boston in mid-February. Heavy snow fell in the North and South Carolina in January and severe ice storms affected those states in December and February.

Around The Globe

The global land surface temperature for the December-February season was less than the record and near-record highs of recent years, but still well above the long-term mean. The average land surface temperature was 1.0° F (0.6° C) above the 1880-2002 mean, the 15th warmest December-February since 1880 (the beginning of reliable instrumental records). The ocean surface temperature tied with two other years as the second warmest on record, 0.8° F (0.4° C) above average, slightly less than the record warm December-February that occurred during the 1997-1998 El Niño episode.

The combined land and ocean surface temperature for December-February was the sixth warmest on record, while the average temperature in the lower troposphere (the lowest 5 miles of the atmosphere) tied December-February 2001-2002 as the second warmest on record . Since 1900, global surface temperatures have risen at a rate of 1.0° F/century (0.6° C/century), but the rate has increased to approximately three times the century-scale trend since 1976.

El Niño conditions prevailed during the period, but were significantly weaker by the end of February, according to NOAA’s Climate Prediction Center. Sea-surface temperature anomalies had decreased by more than 3.5° F (2° C) in the eastern equatorial Pacific and continued weakening is expected.

NOAA’s 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 databases in climatology, oceanography, solid earth geophysics, marine geology and geophysics, solar-terrestrial physics, and paleoclimatology.

The Commerce Department’s National Oceanic and Atmospheric Administration (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 our nation’s coastal and marine resources.

*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.

On the Net:

NOAA: http://www.noaa.gov

NOAA National Weather Service: http://www.nws.noaa.gov

NOAA Satellites and Information: http://www.nesdis.noaa.gov

National and global data: http://www.ncdc.noaa.gov/oa/climate/research/2003/feb/feb03.html