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IRI Climate Digest April 2001

March Global Climate Summary

Climatological Background  In March, the sun crosses the equator (the Equinox) and begins its migration into the Northern Hemisphere. It is the transition from winter to spring in the Northern Hemisphere, when temperatures begin to increase and storm tracks move northward. In the Southern Hemisphere summer is ending and the monsoon rains are retreating northward. 

Monthly Mean Temperature (1961-1990), data from the Climate Research Unit, University of East Anglia
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Monthly Mean Precipitation (1961-1990), data from the Climate Research Unit, University of East Anglia
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Temperatures Over Land

Above average temperatures continued across a broad region extending from northern Africa northward to southern Europe and eastward to the Pacific coast of China.  Much of Canada saw another unusually mild month while temperatures were lower across southern Australia easing unusually warm conditions which had prevailed since January.

Europe:  Above average temperatures persisted across all of southern Europe.
Asia:  Unusually warm conditions extended from Turkey and the Ukraine eastward to China.
Africa:  The region of above average temperatures seen along coastal areas in western and northern Africa over the past few months continued in March and expanded to include much of the interior sections of north Africa. 
Australia:  Temperatures were close to average across southern Australia, easing unusually warm conditions that had prevailed for the past few months.  Much of Western Australia saw below average temperatures.
North America:  Much of Canada was unusually warm during March with many northern and western areas having seen above average temperatures since January.

Temperature Difference from the 1961-1990 mean, with data from NCEP Climate Prediction Center, CAMS.
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Heavy rains eased somewhat in southern Africa.  Unusually dry conditions persisted over parts of western Asia and southeastern Brazil.

Africa:  Rainfall eased somewhat from the previous month but continued above average across northern Mozambique, Zambia, Zimbabwe and Malawi.  Rainfall was mixed over the Greater Horn with eastern sections of Kenya and Ethiopia being somewhat below average with conditions slightly wetter than average across central and western areas.  Much of Tanzania was drier than usual for the month.
South America:  Below average rainfall continued across southeastern Brazil.  Coastal sections of Peru and Ecuador saw above average rainfall as did much of Uruguay and northeastern Argentina.
North America:  Beneficial rainfall fell across the southeastern United States while along the west coast, unusually dry conditions prevailed.
Europe:  Unusually heavy rainfall was observed over much of the Iberian Peninsula.
Asia:  Precipitation continued below average across Afghanistan, Pakistan and Iran.
Australia:  North-central regions of Western Australia saw unusually heavy rainfall as did coastal areas in northern New South Wales.

Precipitation Difference from 1961-1990 mean, with data from NCEP Climate Prediction Center, CAMS-OPI.
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Oceanic Conditions

Tropics:  The modest La Niña conditions in the central Pacific weakened somewhat over the past month while slightly above average sea surface temperatures (SSTs) have developed in eastern areas, especially along the South American coast.  Current statistical and computer numerical models predict an end to the La Niña conditions over the next two months with the development of slightly above average temperatures in the equatorial Pacific by the end of the year. 
Midlatitudes:  Above average SSTs in the North Atlantic have weakened from last month with little change elsewhere.  Warmer than average SSTs persist across the central South Atlantic and South Pacific basins as well as the southern Indian Ocean.  Colder than average SSTs continue across the central North Pacific.

Monthly Sea Surface Temperature Difference from the 1950-1979 mean, with data from the Environmental Modeling Center, NCEP/NOAA.
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Material for this Global Climate Summary has been extracted from the IRI Climate Data Library, the NOAA NCEP Climate Prediction Center, the Climate Diagnostics Center, and the NOAA ERL Pacific Marine Environmental Laboratories. Additional information has been obtained from the Bureau of Meteorology, Australia, and CPTEC, Brazil

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