NOAA 2001-129
Contact: Pat Viets


According to scientists from the National Climatic Data Center, a part of the Commerce Department's National Oceanic and Atmospheric Administration (NOAA), variability was the key descriptor to weather across the globe in 2001. Working from the world's largest statistical weather database, NOAA scientists noted that 2001 is projected to be the second warmest on record for the globe. The scientists also report 2001 saw the fifth most active Atlantic hurricane season, drought in parts of U.S. and record cold in Siberia and western Asia.

Global Temperatures

Based on data received through the year and depending on conditions throughout the remaining two weeks of December, the average annual global temperature is projected to be 57.8°F (14.4°C), which is 0.9°F (0.5°C) above the 1880-2000 long-term average, which would make 2001 the second warmest year on record. The warmest year on record, 1998, occurred during a strong El Niño event and was 1.2°F (0.7°C) above the long-term average. Other years in the top five warmest are 1997, 1995 and 1990. During the past century, global surface temperatures have increased at a rate near 1.1°F/Century (0.6°C/Century), but this trend increased to a rate approaching 3.0°F/Century (1.7°C/Century) during the past 25 years.

U.S. Temperatures

Annual temperatures for the contiguous U.S. are expected to be near 54.0°F (12.2°C), which is above the long-term (1895-2000) average of 52.8°F (11.6°C). Warmer than average temperatures dominated much of the western half of the U.S. throughout most of 2001, while the Southeast experienced cooler than normal conditions during the summer months. Nevada had its record warmest May, August, September and fall season (September-November) in 2001. New Mexico also had its warmest fall on record. Nationally, 2001 had the second warmest November on record; 1999 was the warmest. Alaska experienced its warmest winter (Dec00-Feb01) on record with more than a 12.0°F (6.7°C) departure from the long-term (1918-2000) average. U.S. temperatures have risen at a rate of 0.9°F/Century (0.5°C) over the past 100 years. Within the past 25 years, U.S. temperatures increased at a rate of 1.6°F/25 years (0.9°C/25 years).

Active Hurricane Season

Although the Atlantic hurricane season had a late start, there were 15 named tropical storms in 2001, nine of which became hurricanes with four reaching major hurricane strength. This was the fifth most active season since 1871. On average, between nine and ten named storms form with six growing to hurricane strength and two developing into major hurricanes. A tendency for greater hurricane activity has occurred over the past seven years after more than two decades of generally below-average activity.

Scientists at NOAA's Hurricane Research Division, part of the Atlantic Oceanographic and Meteorological Laboratory in Miami, believe this may be due to a natural ocean cycle called the Atlantic Multidecadal Mode, a North Atlantic and Caribbean sea surface temperature shift between warm and cool phases that lasts 25 to 40 years each. The scientists conducted research that shows warmer sea surface temperatures in the North Atlantic combined with a decrease in vertical wind shear contribute to conditions for more hurricanes over a several-year period.

Five or more major hurricanes (winds in excess of 111 mph) occurred in 1995, 1996 and 1999. Prior to 1995, five or more major Atlantic hurricanes had not occurred in one season since 1964. A new record number of hurricanes for November was set in 2001 as Michelle, Noel and Olga all were active in the Atlantic Basin during the month. The contiguous U.S. has not been hit directly by a hurricane now for the past two years, although tropical storms have caused significant damage, as evidenced by Tropical Storm Allison. This storm, the costliest tropical storm on record ($5 billion in damage), caused severe flooding in Texas and Louisiana before moving across the Southeast and up the East Coast.

Even though the Atlantic hurricane season was above average for the fourth consecutive year, it appears that there were fewer tornadoes in 2001 than average. Eight very strong to violent tornadoes (winds in excess of 158 mph) occurred between March and August 2001. This was much less than the 1950-2000 average of 38. Throughout the past 50 years, there has been little observed trend in very strong to violent tornado activity.

U.S. Drought, Floods and Wildfires

Drought conditions, brought on by an atmospheric circulation pattern during the winter 2000-2001 that deflected storm systems away from the West and inhibited the flow of Gulf moisture from the Eastern states, plagued much of the western, East Coast and New England states in 2001. April 2001 was the driest such month on record for both New York and Maine and during Autumn, drought conditions intensified along the Eastern seaboard due to the lack of Gulf moisture and Tropical activity. Maine will likely have its driest year in the 1895-2001 record. Year-to-date precipitation for Maine is 3.62 inches below the driest annual value of 30.98 inches set back in 1965.

The Great Lakes and Northern Great Plains states experienced wetter than normal conditions. Precipitation across the Great Lakes and northern Great Plains states was abundant with flooding along the Mississippi River in April, while Tropical Storms Allison and Barry caused significant flooding along the Gulf Coast states, ending drought conditions in this region.

The wildfire season in the U.S. began later than usual, but escalated rapidly. The level of activity for the season was similar to the 10-year average (1990-1999), although Florida, Nevada, Washington and Oregon had more active seasons than is typical. Dry conditions contributed to the increased wildfire activity in these states. This near-average season follows the worst fire season in over 50 years last year in the southern and western regions of the country. Almost 3.5 million acres have burned during the 2001 season.

Global Satellite Data

Data collected by NOAA's TIROS-N polar-orbiting satellites and analyzed by the National Aeronautics and Space Administration and the Global Hydrology and Climate Center at the University of Alabama in Huntsville indicate that temperatures in the lower half of the atmosphere (lowest 8 km) were near average over the globe. Based on eleven months of data, satellite measurements of the globe indicate that 2001 ranks as the 10th warmest since records began in 1979. The global satellite temperature record continues to show significantly less warming than global surface temperatures as recently reported in the Intergovernmental Panel Report on Climate Change (2001).

Additional Global Data

Cooler than normal ocean temperatures throughout the eastern equatorial Pacific became more temperate through 2001 as the La Niña of recent years faded to neutral conditions early in the year. Temperatures in the Northern Hemisphere continued to average near record levels.

Drought conditions continued across portions of Pakistan, Afghanistan, India and Iran as the region has suffered from an extreme lack of precipitation for over three years. In Afghanistan, the drought is perhaps the worst in 30 years. Much of Siberia and western Asia experienced their harshest winter in decades. Temperatures ranged from -60°F (-51°C) to as low as -94°F (-70°C) during January and February. Heavy snows in South Korea were the worst in 20 years.

Climate data describing these and other events are available on the Web at:

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