National Overview - Annual 2000


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2000 Global Temperature Anomalies
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Contents of U.S. Report:

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Top of Page National Temperature

U.S. Annual Temperature
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After beginning with record warmth, 2000 ended with colder than normal temperatures across much of the nation. November 2000 was the second coldest such month since 1895 and December 2000 was the seventh coldest December since 1895. The two-month period, November-December 2000, was the coldest such two-month period on record. The January through October 2000 period was the warmest such period on record but the much cooler than normal conditions during November and December dropped the annual ranking for the nation to the 13th warmest year since 1895 with an average annual temperature of 54° F.

Data collected by NOAA's TIROS-N polar-orbiting satellites and adjusted for time-dependent biases by NASA 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 of the atmosphere) were above the 20-year (1979-1998) average for the January-December 2000 period and ranked as the fourth warmest such period since 1979. MSU Annual Temperature Departures
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Percent Warm/Cold
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The adjacent figure shows the percent of the U.S. that was very warm and the percent that was very cold during each of the past 12 months. The record U.S. temperatures in the early months of 2000 are reflected in this figure. More than a fifth of the contiguous U.S. was very warm each month from January through May, and also in August. Unusually cold conditions covered half of the country in November and December. Very warm and very cold conditions are defined as the warmest and coldest ten percent of recorded temperatures respectively.

It was the second warmest year on record for Utah and the third warmest year since 1895 for New Mexico and Nevada. Twenty-one other states were much warmer than normal. Only three states were much cooler than normal for 2000. Annual temperatures averaged across the state of Alaska gave 2000 a rank of sixth warmest year in a period of record that dates back to 1917. Statewide Temperature Ranks
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Top of Page National Precipitation

Percent Wet/Dry
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Despite widespread drought during the summer of 2000, the country had a negative precipitation departure of only 7.1 percent. Drought conditions in the southern and western regions of the country were somewhat offset by wetter than normal conditions in the Great Lakes region and portions of the Northeast. This was the second year of negative precipitation departures after a period of eight out of nine years with positive departures.

Florida experienced the driest year on record during 2000 while it was the eighth driest year for Alabama and the 9th driest for Georgia. Fourteen other states were much drier than normal for 2000. It was the sixth wettest year on record for New York and North Dakota. Twelve other states were much wetter than normal. Statewide Precipitation Ranks
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Top of Page Drought and Wildfires

US Percent Area Very Wet or Very Dry 96-00 larger image On a national scale, long-term drought (as measured by the Palmer Drought Index) expanded from about 16% of the country in the severe to extreme categories in January to a peak of 36% in August 2000. Heavy precipitation in many of the drought areas during the autumn months resulted in a rapid decrease in the drought area, which reached about 6% of the contiguous U.S. by November.

The percent of the country in the severe to extreme wet spell categories (as measured by the Palmer Drought Index) remained steady at about 5% throughout the year.


At its peak, the 2000 drought, when compared to other droughts of the 20th Century, was as extensive as the major droughts of the last 40 years, but not as large as the "dust bowl" droughts of the 1930's and 1950's. US Percent Area Very Wet or Very Dry 1900-2000 larger image

Palmer Drought Index August 2000 larger image At its peak, the 2000 drought affected about 36% of the contiguous U.S. The areas most severely affected included the Deep South, the southern and central Great Plains, and much of the western U.S.

At the peak of the national drought, hundreds of wildfires were burning across several western states, with the greatest concentration occuring in Idaho and western Montana. About 7.3 million acres of land nationally were scorched by wildfires this year (more than twice the area of the state of Connecticut), one of the highest totals in 50 years. Palmer Z and Fires of 8/17/2000 larger image

There is a complex relationship between wildfires and climate variables. The severity of a wildfire season is affected by such things as soil moisture content, vegetation density, moisture content of live vegetation, wind speed, relative humidity, extended periods of abnormally hot temperatures, below-normal rainfall, and the incidence of lightning producing thunderstorms.

The Palmer Z Index is used as a measure of short-term moisture shortages. Research suggests that it is a useful indicator of fire potential. Most of this summer's wildfires occurred in areas experiencing moderate to extreme drought, as seen on an overlay (above) of wildfire location on top of the Palmer Z index map for July 2000. Much of the western fire region was persistently dry since October 1999. This persistent month-after-month extreme dryness resulted in a rapid intensification of long-term cumulative drought conditions, with the Palmer Drought Index for the western fire area reaching its most extreme level since the 1930's.


Record dryness occurred in the Deep South (Alabama, Florida, Georgia, Louisiana, and Mississippi) during 2000. The greatest precipitation deficits occurred in this region from late spring through mid-autumn, with 2000 having the driest May-October period in the last 106 years. Deep South Regional PDI 2000 larger image

The cumulative effect of these extremely dry conditions, which began in the spring of 1998, was a long-term drought which matched the worst drought episodes of the 20th Century (as measured by the long-term Palmer Drought Index). At the peak of the drought, Georgia farmers stopped planting small grains, Alabama Power reservoirs dropped to record low levels, many streams in the region experienced record low flows, and cities imposed water restrictions. Carrollton, Georgia declared a state of emergency due to scarce water supplies.


South Region Precipitation Jul-Sep, 1895-2000 larger image The southern Great Plains (South region) of the U.S. experienced extremely dry conditions during summer to early autumn 2000. July-September 2000 ranked as the driest such period in the last 106 years, easily surpassing the drought years of the 1950's. Many stations set new low precipitation records, including all-time records for most consecutive days with no rain. The extreme dryness was accompanied by searing heat, which had a major impact on agriculture. A Texas A&M University study reported state agricultural losses of $1.1 billion, the largest drought loss in the nation this year.

Torrential rains in November ended the drought and brought flooding to many cities throughout Texas and surrounding states. November was the wettest such month on record in the South region which experienced extreme drought only months earlier. Precipitation Deficits/Surpluses SPI-3 Jul-Sep 2000 larger image

Top of Page Severe Storms

Observed Tornadoes, US Mar-Aug 1950-2000 larger image There were 16 very strong to violent tornadoes (wind speeds in excess of 158 mph, category F3-F5) during the 2000 tornado season (March-August). This is well below the long-term (1950-1999) mean of 38 and ties with 1978 and 1986 as the third lowest such tornado count in the last 50 years. Little trend in very strong to violent tornados has been observed since 1950.

There were 14 named tropical storms in 2000, eight of which became hurricanes with three reaching major hurricane strength. On average, nine named storms form with seven growing to hurricane strength and two developing into major hurricanes. A tendency for greater hurricane activity has occurred over the past six years after more than two decades of generally below-average activity. Observed Hurricanes, US larger image
Five or more major hurricanes occurred three times in the 90's; 1995, 1996 and 1999. (A major hurricane is defined as category 3 or higher according to the Saffir-Simpson scale. A category 3 hurricane has winds 111-130 mph). Prior to 1995, five or more major Atlantic hurricanes had not occurred in one season since 1964.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: National Overview for Annual 2000, published online December 2000, retrieved on August 1, 2014 from http://www.ncdc.noaa.gov/sotc/national/2000/13.