Major Highlights
WIDESPREAD U.S. DROUGHT CONTINUES
U.S. HAS FOURTH WARMEST SPRING, FIFTH WARMEST MAY ON RECORD
GLOBAL TEMPERATURE WARMER THAN AVERAGE
The contiguous United States experienced its fifth warmest May and fourth warmest spring since records began in 1895, while overall precipitation remained below average, according to scientists at NOAA?s National Climatic Data Center in Asheville, N.C. The NCDC also reported that the June 2005 ? May 2006 period was the warmest on record for the contiguous U.S. The continuation of below-normal precipitation combined with much warmer than average temperatures led to persistent, or in some cases worsening, drought conditions in many parts of the nation. Meanwhile, portions of New England experienced flooding in May, as a series of storms set many local rainfall records. The global surface temperature was fifth warmest on record for May.
U.S. Temperature
The average temperature for the contiguous United States for May (based on preliminary data) was 63.7°F (17.6°C), or 2.7°F (1.5°C) above the 20th century (1901-2000) average, the fifth warmest May on record. The March-May period was the fourth warmest spring for the contiguous U.S, and four states (Arkansas, Oklahoma Kansas, and Texas) experienced their warmest spring on record. No state had below average spring temperatures, and only California was near average. This continued the string of warmer-than-average conditions over the past year in the contiguous United States.
Since the start of last summer, six months have been much warmer than average including two months (January and April 2006) which were warmest on record, and the 12-month period was the warmest on record. The anomalous warmth has covered all parts of the country with statewide records established in Maryland, New Jersey, New York, Vermont, Michigan, Wisconsin, Minnesota, Iowa, North Dakota and New Mexico. Statewide for Alaska eight of the past twelve months were warmer than average, and the June-May temperature was the 20th warmest since records began in 1918.
U.S. Precipitation
May 2006 precipitation across the contiguous United States was below average, at 2.33 inches (59 mm), 0.54 inches (14 mm) below the 20th century average. Most of the central U.S. was drier than normal, but only Nebraska and Iowa were much drier than average. A series storms in the northeastern U.S..resulted in above, to well-above normal rainfall totals from Michigan and Indiana across to New England. New Hampshire and Massachusetts both experienced their second wettest May on record, largely due to the exceptional rainfall event of May 10-15, when accumulations of between 12 and 17 inches (300-430 mm) of rain occurred in some localities of southern New Hampshire and northeastern Massachusetts.
Spring 2006 was also drier than average for the contiguous United States, with the most anomalously dry conditions along the eastern seaboard from New Jersey to Florida. Areas from the Gulf Coast to Wyoming were also drier than average. Parts of the Far West, northern Rockies and Midwest, along with Vermont and New Hampshire were wetter than average.
Persistent drier-than-average conditions over the past several months, combined with much above average to record warmth, worsened drought conditions. By early June, moderate-to-severe drought was present throughout a large part of the south-central U.S., with extreme and exceptional drought occurring in the parts of the Desert Southwest, southern Plains, and southeastern Louisiana, according to the U.S. Drought Monitor. Moderate drought developed in central Florida and grew in parts of the southern Appalachian region. Fully 39 percent of the contiguous United States was in moderate-extreme drought, while 20 percent was in severe-to-extreme drought, as defined by the Palmer Drought Index, a widely-used measure of drought. Above average precipitation alleviated moderate drought conditions in the Upper Peninsula of Michigan, and conditions improved in areas that included eastern Oklahoma, southern Florida, and parts of the Northeast.
Globe
The eastern North Pacific Hurricane season officially began May 15, and Tropical Storm Aletta formed southwest of Acapulco, Mexico May 27. Aletta reached maximum sustained winds of 40 kt and a central pressure of 1002 mb before moving out to sea and dissipating on May 30.
For global land and ocean surfaces, this was the fifth warmest May since records began in 1880 (0.90°F/0.50°C above the 20th century mean) and sixth warmest boreal spring (March-May) (0.92°F/0.51°C). The warmest March-May occurred in 2005 (1.19°F/0.66°C above the 20th century mean). Land surface temperatures for May were above average across southern Europe and Scandinavia, eastern and southwestern Asia, and much of North America. Unseasonably cold May weather occurred in central South America, as well as in South Africa and Lesotho, where it wasaccompanied by an uncommon mountain snowfall. An early May heatwave produced temperatures over 104°F (40°C) across India, claiming more than 50 lives.
NOAA, the National Oceanic and Atmospheric Administration, an agency of the U.S. Commerce Department, 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. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners and more than 60 countries to develop a global monitoring network that is as integrated as the planet it observes.
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