ENERGY DEMAND DECREASES AS U.S. EXPERIENCES TENTH WARMEST WINTER, PRECIPITATION NEAR AVERAGE FOR THE NATION
March 16, 2005 ó The United States experienced its tenth warmest winter on record, according to scientists at the NOAA National Climatic Data Center in Asheville, N.C. Nationwide, temperatures from December 2004 - February 2005 were much above normal, as drier-than-average conditions persisted in the Northwest and heavy precipitation affected the Southwest. The global average temperature was fourth warmest on record for December-February. (Click NOAA image for larger view of winter 2004-2005 state temperature rankings. Please credit “NOAA.”)
Based on preliminary data, NOAA reports that the average temperature for the contiguous United States this winter was 35.9 (2.2 degrees C), which was 2.8 degrees F (1.6 degrees C) above the 1895-2004 mean. The mean temperature in 39 states was above average. No state was cooler than average during the winter. Alaska was warmer than average with a statewide temperature of 4.0 degrees F (2.2 degrees C) above the 1971-2000 mean, ranking fifteenth warmest since statewide records began in 1918. Despite several cold outbreaks in the Northeast, the relatively warm winter season nationwide led to below-normal heating degree days and below-average residential energy demand for the country, as measured by the nation's Residential Energy Demand Temperature Index. It was the fifteenth lowest index value in the 110 year record for December-February.
Winter precipitation was near average for the nation overall, with unusually dry conditions in the Northwest, parts of the northern Plains and the Southeast countering above average wetness from the Southwest to the Great Lakes and Northeast. Beginning in autumn 2004, a series of Pacific storms brought above average, and in some cases, record precipitation to the Southwest. Downtown Los Angeles had 29.1 inches of rain during the winter, exceeding the normal winter rainfall by more than 20 inches. Record precipitation for the water-year to date (Oct. - Feb.) was recorded at stations across parts of the Southwest, especially in Utah. The above average precipitation also led to recovery in reservoir levels for the Southwest. In Arizona, statewide reservoir levels were above average on March 1, the first time since 2001 the winter season ended with average or above average reservoir levels.
At the end of winter, moderate-extreme drought (as defined by a widely used measure of drought—the Palmer Drought Index) affected 72 percent of the Pacific Northwest (Wash., Ore., Idaho).
This is dramatically higher than the 14 percent affected on December 1 but below the recent peak of 92 percent in November 2002 and the all-time record of 100 percent most recently set in 1977. More than 60 percent of the broader Northwest (Wash., Ore., Idaho, Mont., Wyo.) was also in moderate-to-extreme drought at the end of the winter. Record low precipitation for the water year-to-date was measured at many stations in Washington, Oregon, Idaho, Montana and Wyoming.
While rain fell along the southern California coast during the winter, snow fell in the Sierra Nevada and mountainous Southwest. Snowpack was more than 150 percent of average in the southern Sierras and across parts of southern Nevada and Utah. New Mexico and Arizona also had widespread above average snowpack as of March 1. Contrasting the above average snowfall in the Southwest was a lack of snow in Northwest. Less than 25 percent of average March 1 snowpack existed in the western half of Washington and Oregon and widespread areas with less than 70 percent of average snowpack were evident across most of the Northwest.
The average global temperature anomaly for combined land and ocean surfaces during December-February (based on preliminary data) was 0.9 degrees F (0.5 degrees C) above the 1880-2004 long-term mean. This tied 1999 as the fourth warmest boreal winter since 1880 (the beginning of reliable instrumental records). Above average temperatures stretched from northern Europe into Siberia and also covered large parts of southern Asia, Africa, Australia and western Canada. Colder-than-average conditions occurred in much of eastern Canada, northwest Africa, parts of southern Europe and central Asia. Weak El Niño conditions persisted into February with sea-surface temperatures in much of the central equatorial Pacific remaining warmer than average for the season, and the December-February global ocean surface temperature was second warmest on record.
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