NOAA REPORTS DECEMBER WARMER THAN AVERAGE, GLOBAL TEMPERATURE WARMER THAN AVERAGE
Jan 18, 2005 ó The national average temperature for December 2004 was above normal for the contiguous United States, according to scientists at NOAA Climatic Data Center in Asheville, N.C. While much of the western half of the nation was warmer than average, a brief period of very cold temperatures and heavy snowfall occurred in the Midwest and parts of the South, where temperatures averaged near the long-term mean (1895-2003). The global average temperature for December was fifth warmest on record. (Click NOAA image for larger view of selected global significant events from December 2004. Please credit “NOAA.”)
NOAA scientists report that the average temperature for the contiguous United States for December (based on preliminary data) was 35.7 degrees F (2.1 degrees C), which was 2.2 degrees F (1.2 degrees C) above the 1895-2003 mean. This was the 23rd warmest December on record. The mean temperature in 19 states was above average, with all but one (New Hampshire) of these states being west of the Mississippi River. Three western states (Montana, Wyoming, Nebraska) were much warmer than the long-term mean, while only two states in the contiguous United States (Mississippi, Louisiana) were cooler than average for the month. The relatively warm temperatures for the nation led to below-normal heating degree days and below average residential energy demand. The nation's Residential Energy Demand Temperature Index was the 35th lowest on record for December. The December temperature ranking of 23rd warmest is close to that for all of 2004 as a whole, which ended as the 24th warmest year on record.
Alaska was warmer than average for December with a statewide temperature of 4.5 degrees F (2.5 degrees C) above the 1971-2000 mean. The year as a whole was much warmer than average for Alaska, ranking as the fourth warmest since statewide records began in 1918.
December precipitation was near average for the nation overall, however, dryness in the central U.S. balanced above-average wetness in the Southwest and Northeast.
The last few months of 2004, and the year as a whole, were much wetter than average, with the year ending as the sixth wettest on record. The latter half of 2004 ranked second wettest for any July-December in the last 110 years, partly as a result of multiple land-falling tropical systems, and much above-average rain and snowfall in areas of the Southwest.
The wetter-than-average conditions in parts of the West in 2004 helped alleviate drought that has been entrenched for more than five years in some western locations. Although hydrological deficits still remain in much of the West, moderate-extreme drought affected only 10 percent of the western U.S. at the end of December, based on a widely used measure of drought, the Palmer Drought Index. This compares to 69 percent in March of 2004—the peak of the 2004 drought.
After a relatively slow start to the 2004-05 winter season for many parts of the country, a major snowstorm affected much of the Midwest in late December, causing major disruptions throughout the region. Some cities in the Midwest received more than their annual average snowfall in a single day. Residents in cities such as Paducah, Ky., and Evansville, Ind., had snow totals exceeding a foot, with more than two feet being reported in places such as Scottsburg, Ind., and across a large area of the western Ohio Valley. Snowfall was also recorded in Brownsville, Texas, for the first time since February 1895, with 1.5 inches falling on Christmas day. Further north, Victoria, Texas, received more than a foot of snow from the same storm, a record for the city.
The average global temperature anomaly for combined land and ocean surfaces during December 2004 (based on preliminary data) was 0.79 degrees F (0.44 degrees C) above the 1880-2003 long-term mean. This was the fifth warmest December since 1880 (the beginning of reliable instrumental records). Although land surface temperatures were anomalously warm throughout Europe, Scandinavia and western North America, cooler-than-average conditions were widespread across eastern and northern Canada, as well as much of Asia. Weak El Niño conditions persisted into December with sea-surface temperatures in much of the central and east-central equatorial Pacific remaining warmer than average for the month, and the December global ocean surface temperature was second warmest on record. The warmer than average December concludes another much warmer than average year for the globe—4th warmest since 1880.
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