May 16th, 2007 12:30 EST
Global April Surface Temperature Third Warmest on Record
The contiguous U.S. temperature for April 2007 overall held to near average, while the surface temperature was third warmest on record globally, according to scientists at the NOAA National Climatic Data Center in Asheville, N.C. April began with a record cold outbreak that stretched from the Plains to the Southeast, bringing widespread crop and forest damage. Drier-than-average conditions in the Southeast led to worsening drought conditions, while a strong Nor'easter brought severe flooding to parts of the Northeast.
U.S. Temperature Highlights
For the contiguous U.S., April's average temperature was 51.7 degrees F (10.9 degrees C), which was only 0.3 degrees F (0.2 degrees C) below the 20th century mean (based on preliminary data).
The record cold outbreak from April 4 to 10, produced crop losses that could reach into the billions of dollars, according to agricultural experts. Approximately 1,200 daily low temperature records were set during the 7-day period.
According to the NOAA Air Resources Laboratory, the cold snap killed vegetation and reduced tree leaf area causing more of the sun's energy to be used for heating the atmosphere instead of evaporating water from vegetation. Such impacts can result in warmer air temperatures and less moisture in the atmosphere in a region where drought conditions already exist.
Alaska had its fourth warmest April on record, with a temperature 5.96 degrees F (3.3 degrees C) above the 1971-2000 average.
Cooler-than-average April temperatures in the eastern U.S. helped increase residential energy needs for the nation. Using the Residential Energy Demand Temperature Index (REDTI—an index developed at NOAA to relate energy usage to climate), the nation's residential energy demand was approximately 1.5 percent higher than what would have occurred under average climate conditions for the month.
U.S. Precipitation Highlights
The contiguous U.S. was drier than average in April. Abnormally dry conditions were widespread throughout the Southeast and Pacific Northwest, while much wetter-than- average conditions stretched from Maine to New Jersey.
The wetness in the Northeast resulted from a strong Nor'easter that impacted the East Coast from April 15 to 17. Heavy rainfall triggered flooding in areas of the mid-Atlantic and Northeast. New York City had its second-rainiest day ever, with 7.57 inches April 15.
Drier-than-average conditions persisted across much of the Southeast. Precipitation for the first four months of the year was less than 50 percent of average in some areas, and severe drought stretched from western North Carolina and Tennessee to southern Mississippi by late in the month, with extreme drought affecting much of northern Alabama.
Extreme drought in southern Georgia led to reports of the largest wildfire on record for the state.
The water year (July 1-June 30) in Los Angeles continued to be the driest on record and severe-to-extreme drought stretched from the southern California coast to Arizona and north along the Sierra Nevada Mountains, where seasonal snowpack was less than 50 percent of average.
The combined global land and ocean surface temperature for April was the third warmest on record (1.21 degrees F/0.67 degrees C above the 20th century mean). The global surface temperature for the combined January-April period was the warmest on record.
Separately, the global April land-surface temperature was the warmest on record. Elevated monthly mean temperatures—more than 5 degrees F (3 degrees C) above average—covered large parts of Asia and Western Europe. The April ocean-surface temperature tied for seventh warmest in the 128-year period of record as neutral ENSO (El Niño-Southern Oscillation) conditions persisted in the equatorial Pacific.
During the past century, global surface temperatures have increased at a rate near 0.11 degrees F (0.06 degrees C) per decade, but the rate of increase has been three times larger since 1976, or 0.32 degrees F (0.18 degrees C) per decade, with some of the largest temperature increases occurring in the high latitudes of the Northern Hemisphere.
NOAA, an agency of the U.S. Commerce Department, is celebrating 200 years of science and service to the nation. From the establishment of the Survey of the Coast in 1807 by Thomas Jefferson to the formation of the Weather Bureau and the Commission of Fish and Fisheries in the 1870s, much of America's scientific heritage is rooted in NOAA. NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of the nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 60 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.