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  • Global Temperature
    
  • Regional and Seasonal Variations in the Global Temperature Picture
    
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  • Precipitation in the United States
    
  • Global and U.S. Natural Disasters
    
  • 1999 Monthly Reports
    
    

Global temperatures for 1999 are expected to be the 5th warmest on record since 1880. Globally the departure from the long-term average (1880-1998) was 0.42 degrees C (0.76F).

Land temperatures continued near-record warmth (averaging 13.9 degrees C or 56.9F; 0.79 degrees C or 1.42F above the long term average) second only to 1998, but ocean temperatures were the lowest since 1994. Just as the warm oceans associated with El Niño last year contributed to the record high temperatures, the cooler ocean conditions in 1999 associated with La Nina helped to ameliorate what might otherwise have been an even warmer year. Although ocean temperatures were among the lowest of the past decade, they still averaged 15.5 degrees C (59.8F) or 0.26 degrees C (0.47F) above the long-term average.

We are certain that the near-surface temperatures during the Twentieth Century have been rising. A long-term temperature increase of 0.6 degrees C/century (1.1 degrees F) has occurred during the 20th Century. There have been two sustained periods of warming, one beginning around 1910 and ending around 1945, and the most recent beginning about 1976. Temperatures during the latter period of warming have increased at a rate of 0.2 degrees C/decade. This is comparable to the rates of warming projected to occur during the next Century with continued increases of anthropogenic greenhouse gases.

Our annual values are based on estimated values for December. Values for 1999 include an estimate for global temperatures for December, based on persistence from November. Updated values for 1999 will be available on January 14, 2000. For the meteorological year (last winter through the autumn; December 1998-November 1999) our 1999 annual global temperature estimates are identical to the global temperatures for the calendar year.

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The above (Fig 1.) average land temperature for the globe (based on the period 1880-1998) was primarily due to continued warmth over most of the Eurasian and North American land masses. In June and July, Russia experienced one of its longest heat waves of the century. Maximum temperatures in Moscow were last equaled in 1895. In parts of central and northern Europe, September was the warmest in this century with recorded anomalies in Germany exceeding 8 degrees F above the long-term average. Global land temperatures for November were the warmest on record. However, most of Europe was colder than average in February which led to above average snowfall, particularly across the Alps region. Portions of the southern hemisphere land mass temperatures were near to below average for the year. Temperatures in western and southern South America were below average due to the La Nina-induced cool sea surface temperatures in the eastern equatorial Pacific and central and southern Africa was also cooler than average for the latter half of the year. The Sahel region, in particular was cloudier and cooler than in recent years.

The above (Fig 2.) is a result of merging several sources of data. Data used in the blended surface temperature product include: surface temperature data using in-situ land stations, satellite data, and a sea surface data set. The climatological base period is 1992-1999. Note the similarity of trends in both figures.

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For the calendar year 1999 we project that the United States will have experienced its second warmest year on record since 1900 with an average for 1999 of 55.7 degrees F. This follows 1998's all time record of 56.4 degrees. Both year�s values exceed those experienced during the warm decade of the 1930s. The rank of 1999 relative to other years is unlikely to change in updated statistics. For the meteorological year (December 1998-November 1999), the average for the U.S. was 55.90 degrees F, and this was the second warmest on record. Similar to the global temperature trend, 1999 continues a trend toward long-term warming in the U.S.( 0.5 degrees C per Century) with much of the warming occurring during the two periods 1910-45 and 1976-present. The time series graph is based on NCDC's U.S. Historical Climatology Network a high-quality moderate sized data set of monthly averaged maximum, minimum, and mean temperature and total monthly precipitation developed to assist in the detection of regional climate change.

For the calendar year 1999 we expect every state except California to be above normal and 22 states from the Rockies to Maine much above normal. Numerous records for warmth (national, state and city) were set during the year and temperatures for November turned out the be the warmest on record. During November, eight states from the Northwest to the Great Lakes were ranked as having the warmest November on record and 39 states were ranked as much above normal. Numerous urban locations set records for the warmest temperature ever in November and one state (South Dakota) set a state record for the warmest temperature ever recorded in the state for the month. Other heat episodes of note occurred during February (3rd warmest nationally) and during July and August when many locations in the Ohio Valley and eastern seaboard set monthly or all time records for heat. The heat continued into September in the Northeast with New England states experiencing one of the warmest on record.

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Widespread spatial variability in precipitation was noted in 1999. Severe drought affected western Russia during the early summer heat wave resulting in numerous forest fires. The long standing dryness in the Middle East intensified during the year with low water levels reported in Israel and Syria. An early season drought in the Sahel region of Africa was alleviated by a significant wet regime that began in July and continued until November. Areas in the western Sahel experienced flooding rains in September and October. Similarly, dry conditions in eastern China in the early part of 1999 were alleviated by significant rainfall beginning in March. Continued heavy rainfall resulted in severe flooding (although not as severe as 1998 floods in the same area) along the Yangtze River in July. In South America, dryness in the Paraguay/Uruguay region continued to worsen late in the year. Central Europe experienced above normal precipitation during the winter months with one of the heaviest snowfall seasons in the past 50 years in the Alps. Warmer temperatures with snow melt and above normal rainfall led to severe flooding during the Spring in eastern Europe. In southwestern Europe, precipitation was well above average in September and October. Although the monsoon was weaker than average in western India, a strong monsoon and a number of tropical systems resulted in well above average precipitation and consequent flooding in eastern India and Bangladesh.

Precipitation trends in the mid-latitude band (30N-55N) in the Northern Hemisphere show an approximate 7% increase over the past Century. However, for 1999, precipitation in this band was near normal following a record year in 1998 due to El Niño conditions. Precipitation in the band from 10N-30N was the greatest since the 1950s, with above average values across the Sahel, Southeast Asia and the Caribbean. The mid-latitude band in the Southern Hemisphere (30S-55S), which also shows a 7% increase over the past Century, was significantly wetter than 1998, with 1999 ranked as the third wettest year of this decade.

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The United States experienced a near normal year for precipitation, with nationally averaged precipitation of 30.60", which was 1.05" below average. Although the national value was not unusual, there were significant spatial and temporal variations during 1999. The year began on a wet note in the eastern portion of the U.S.; however, a dry regime that became established in April led to record setting growing season dryness throughout the Ohio Valley and Northeast. This was the driest or second driest April-July period in all states from West Virginia to Maine. For the 12-month period from September 1998-August 1999, most of these states experienced either record or near record dryness in the 105 years of data. The drought was followed by record setting rainfall as two hurricanes traversed the eastern seaboard in September. States from North Carolina to Maine experienced a record or near record wet September and numerous location reported their heaviest 24-hour precipitation, wettest September or wettest any month on record. The time series graph is based on NCDC's U.S. Historical Climatology Network a high-quality moderate sized data set of monthly averaged maximum, minimum, and mean temperature and total monthly precipitation developed to assist in the detection of regional climate change.

In the Pacific Northwest, La Nina induced precipitation produced locally heavy rainfall totals with locations in western Washington reporting their wettest February and wettest water-year on record. Cold temperatures led to a record setting snow pack in the northern Cascades with Mt Baker, Wash., setting a U.S. record for the most snowfall in a snow season (1140"). The snowmelt from the this snow pack provided sufficient irrigation for crops as the conditions in the region turned very dry in the late Spring and Summer seasons.

The Upper Mississippi Valley area continued to experience a long term wet regime with the precipitation for September 1998-August 1999 setting a record in Minnesota with near record totals in surrounding states.

Historical precipitation records for the U.S. show an annual increase of approximately 2.1 inches over the past 100 years. This is consistent with a long term increase of 5 to 10 percent. However, 1999 is the first year since 1989 with an annual total (30.60 inches) below the long term average of 31.65 inches, and is the driest year since the drought year of 1988.

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Globally, the most significant disaster occurred in eastern India in October when two cyclones (the second of which was one of the most intense ever observed in the Bay of Bengal), struck the area. Flooding and storm surge resulted in a preliminary estimate of 10,000 fatalities. Snow melt in eastern Europe in May caused extreme flooding on the Danube River with losses amounting to one billion German Marks. Exceptionally heavy snowfall in the Alps resulted in one of the worst avalanche seasons in the Alps in this Century with at least 50 fatalities.

China reported hundreds of fatalities, with nearly 2 million people displaced, in mid-year as heavy rainfall flooded the Yangtze River for the second consecutive year. Monsoon rains also resulted in hundreds of fatalities in Korea and the Philippines in August. Heavy precipitation in Vietnam in November and December produced the worst flooding of this century with 1 million people reported homeless and nearly 700 fatalities. Flooding rains also led to numerous casualties in the normally arid west Sahel region.

In the Atlantic, another above average hurricane season, when combined with seasons beginning in 1995, produced a 5-year period with the greatest number of tropical systems on record. Hurricane Floyd struck the North Carolina coast in September with rainfall producing floods exceeding the expected 500-year event. Floyd was the fifth hurricane in 3 years to affect this portion of the U.S. coastline. 1999 also produced five category 4 hurricanes, the greatest number in any one year on record. These flooding rains alleviated a multi-month drought in the eastern U.S. which resulted in the driest growing season on record in most of the states from west Virginia to Maine. This increase in the Atlantic basin is partially due to above average sea surface temperatures and may signal a return to increased tropical activity that characterized the 1950s and 1960s. The 1970-1990 period was characterized by less frequent and relatively less intense tropical systems with minimal number of landfalls, especially in areas with large population growth and infrastructure development.

In the United States, over 200 tornadoes were observed in January, nearly 14 times the average number. In May, a series of strong tornadoes affected Oklahoma, Kansas and Texas resulting in over 50 fatalities. Through November, the U.S. experienced the second greatest number of tornadoes on record, following 1998's record year. Although annual totals show a long term increase since the 1950s, much of this increase is attributed to improved observing capabilities. There is no apparent change in the frequency of strong-to-catastrophic tornadoes (F3 and above), the type of tornadoes that rarely go undetected.

For more information, refer to ...

The Global Temperature Anomalies

SSMI Derived Products NOAA's National Climatic Data Center is the world's largest active archive of weather data. The preliminary temperature and precipitation rankings are available from the center by calling: 828-271-4800 or on the World Wide Web at: http://www.ncdc.noaa.gov/ol/documentlibrary/cvb.html#1999

Historical precipitation and temperature ranking maps are also available on the Internet at the NOAA/Climate Prediction Center Data and Indices.

NOAA works closely with the academic and science communities on climate-related research projects to increase the understanding of El Niño and improve forecasting techniques. NOAA's Climate Prediction Center monitors, analyzes and predicts climate events ranging from weeks to seasons for the nation. NOAA also operates the network of data buoys and satellites that provide vital information about the ocean waters, and initiates research projects to improve future climate forecasts.

For further information, contact:

Mike Changery
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4750
email: mchangry@ncdc.noaa.gov

David Easterling
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4675
email: david.easterling@noaa.gov

Tom Ross
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4499
email: tom.ross@noaa.gov

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