The persistent cold sea surface temperature anomalies in the east equatorial Pacific are one of the most prominent features in the seasonally averaged map. Some other prominent features include the trough in western North America, where temperatures were below average, and a ridge in the northeastern section of the continent, where temperatures were above average. For the season as a whole, the surface temperature reflection of the mean atmospheric flow pattern can be seen in the warm anomalies (ridge) in Europe, cold anomalies (trough) over western Russia, warm anomalies (ridge) in Central Russia, and cool anomalies (weak trough) over Eastern Russia.

Most of the land mass around the Mediterranean Sea experienced above average temperatures for the spring season. The periphery of Australia was cooler than usual, associated with an area of above average rainfall. The interior of the continent was warmer than usual. Most of South America was cooler than average, which is in concert with the La Niña signal in the Pacific. The above average rainfall and cloud cover of southern Asia left that area cooler than average. Southern Africa was warmer and drier than usual, while further north, near the Indian Coast, rainfall was above average and the temperatures were cooler than expected.

Seasonal Global Snow Cover

A persistent trough over the northwest coast of North America kept snow covering the ground in many areas through the most of the spring, whereas further to the east, a persistent ridge forced the snow to melt much earlier than expected. Similarly the snow pack melted earlier than usual over central Europe, while unusually cold air over eastern Russia, allowed the snow season to extended later than usual into the spring season.

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The mean (boreal spring) Mar-May atmospheric flow pattern brought above average temperatures into central Russia, causing the snow to melt earlier than usual. Dry conditions over southwestern Russia and the Ukraine promoted a below average snow season. Cold air over eastern Russia and northeastern China promoted above average snow cover. As a whole the snow pack across the Tibetan Plateau was below the average of the last 8 years.

Seasonal Surface Wetness for Asia

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Most of China was drier than usual this spring. Conditions were worst at the beginning of spring, and improved as the season progressed. The monsoon season in Indochina started earlier than expected, causing extremely wet surface conditions by the end of the season. Most of southern Asia was drier than normal, however this situation reserved over the Indian sub-continent in May as the monsoon rain began to fall. It remained drier than expected over southwestern Asia throughout the entire spring.

Seasonal Global Temperatures for Africa/Middle East

Warm seasonal anomalies were observed over portions of the Middle East where a combination of low rainfall and warm temperatures led to drought conditions during the March - May period. A ridge of high pressure dominated north Africa during much of the season. Excessive solar radiation and reduced evaporation promoted above average temperatures over southern Africa. Cooler than usual temperatures were observed across portions of the Great Rift Valley in eastern Africa, northern Zaire, southern Central African Republic and southern Angola.

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Seasonal Surface Wetness for Africa/Middle East

The Sahel region across northern Africa started off with a weaker than average rainy season this spring. Warmer temperatures in northwestern Africa melted the snow pack in the Atlas mountains earlier than usual. This will likely mean that less water is available for irrigation as the year progresses. Most of central Africa had ample rainfall; there are isolated areas where surface wetness was well above average. Most of southern Africa was much drier than average. Drought conditions are a concern at some of these locations. Drought conditions are the "worst in decades" according to U.N. officials in parts of the Middle East this March-May period.

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Seasonal Global Temperatures for South America

Near to below normal temperatures covered the entire South American continent. Climatologically in a La Nina pattern a good deal of South America is on the cool side, this pattern was stronger and more widespread than expected. The coolest anomalies were centered near the Paraguay- Bolivia, and Argentine border during the March - May period. The only small exception were warm seasonal anomalies across eastern Brazil.

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Seasonal Surface Wetness for South America

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Large areas of South America were drier than normal during the period March through May. These areas include much of southern Argentina, where a ridge of high pressure limited the amount of precipitation that fell during the season. It was also drier than usual over much of northeastern Argentina, southern Brazil, and Paraguay. Additional sections in Bolivia were drier than expected. Wetter than normal conditions include Central Argentina, and some isolated areas in the far northern section of the continent, where localized flooding was reported.

Basist, A., N.C. Grody, T.C. Peterson and C.N. Williams, 1998: Using the Special Sensor Microwave/Imager to Monitor Land Surface Temperatures, Wetness, and Snow Cover. Journal of Applied Meteorology, 37, 888-911.

For all climate questions other than questions concerning this report, please contact the National Climatic Data Center's Climate Services Division:

Climate Services Division
NOAA/National Climatic Data Center
151 Patton Avenue, Room 120
Asheville, NC 28801-5001
fax: 828-271-4876
phone: 828-271-4800
email: ncdc.orders@noaa.gov

For more information, refer also to ...
SSMI Derived Products
Global Historical Climatology Network (GHCN)
The Blended GHCN - SSM/I Product
The Global Temperature Anomalies

Alan Basist
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: alan.basist@noaa.gov

Tom Ross
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: tom.ross@noaa.gov

Mike Changery
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: mchangry@ncdc.noaa.gov

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