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Temperature anomaly patterns changed significantly during March from what they were in February. The cold water off the west coast of South America warmed somewhat, although mature La Niña conditions in the east equatorial Pacific are predicted to remain for the next few months. There were warmer than average temperatures in March in central Australia and east central South America. The warm anomalies over the eastern U.S. during January and February shifted to colder than average temperatures in March. Conversely, the cold anomalies in February over Europe shifted to above average temperatures. The extreme warmth in eastern China abated somewhat, particularly near the coast. March did bring a continuation of unusually warm temperatures to New Zealand, northern Indochina, north central and southern Africa, the eastern Mediterranean, eastern Canada and north central U.S. Cold anomalies in western Australia and the east coast of Africa continued for the second month in a row.

Temperature

Mean monthly temperature anomalies for March (using a base period 1880-1998) are shown in the figure below. Global temperatures continued to be well above average in the month of March. The average temperature over land and ocean was 0.54 C above the long term mean (1880-1998). Although this was the 4th highest March anomaly on record, the average temperature was 0.21 C less than the average temperature for March 1998.

This continues a trend toward cooler temperature anomalies (but still above the long term average) that began last year with the transition from El Niño to La Niña conditions. In recent months, sea surface temperature measurements showed the most significant cooling. March land surface measurements indicate that significant cooling is now occurring over land areas as well. March land surface temperatures were 1.05 C above the long term mean, 0.21 C less than the average for March 1998.

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This figure shows widespread areas of above average land surface temperatures in March 1999. Some of the largest positive anomalies occurred in Canada and the northern U.S. where anomalies exceeded 5.0 C. The average temperature for this region was 5.20 C above the long term mean, only 0.47 C less than the largest anomaly on record for this region. Areas of the eastern U.S. that had been above average in January and February experienced slightly cooler than average temperatures in March.

Europe, which was only slightly warmer than usual in February, recorded well above average temperatures in March. Anomalies were greater than 4.0 C in Germany, Poland and northern regions of Scandinavia. Above average temperatures also occurred throughout India, China, the Far East, the Mediterranean and parts of Africa and South America. The extremely warm temperatures throughout Canada are a sharp contrast to the large region of cold anomalies across Russia and Mongolia. Below normal temperatures recorded in Siberia throughout the winter months spread south into Central Russia and Mongolia in March as a low pressure trough extended its influence into this region. Temperatures averaged 4.4 C below the long term mean, the coldest since 1960. Alaska also continued a stretch of colder than average months, with anomalies as much as 2.0 C below average.

The persistance of the temperature patterns over the past few months can be seen in this figure of the anomalies for the 3-month period January through March. Above average temperatures were widespread across almost all of Canada and central United States during this period. Warmer than average temperatures also stretched from Europe to the Far East. Areas of below average temperatures can be seen in Alaska, Siberia and southern areas of South America, with isolated areas of slightly below average temperatures in other areas of the world.

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Precipitation

As shown in the adjacent figure, global precipitation averaged more than 7.0 mm (0.28 inches) above the long term mean (1900-1998) in March. This was the 3rd month in a row with above normal precipitation. Although the globally averaged anomaly was strongly positive, in areas for which data were available, the following spatial distribution plot of precipitation anomalies shows that there was a nearly even distribution of positive and negative anomalies across the globe.

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Areas along the eastern coast of China, that have been experiencing drought conditions throughout the past several months, received above average rainfall in March. However, much of China remained drier than normal, exacerbating already dry conditions. Rainfall was as much as 50 mm (2 inches) below average across a large part of south central China. The dry conditions stretched west into India and Pakistan where precipitation averaged 36.4 mm (1.4 inches) below average.

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Many islands of the South Pacific, that had been wetter than average through the first 2 months of the year, continued to receive above average rainfall in March. Above average rainfall also fell across portions of northeastern and western Australia. Precipitation was more than 100 mm (4 inches) above average in some coastal areas. Japan and North and South Korea were also wetter than usual, averaging 23 mm (1 inch) above the long term mean for the month.

Drier than average conditions persisted across a large portion of South America, while much of the southern half of the continent was wetter than usual. Precipitation across Argentina averaged 44 mm (1.7 inches) above average in March. Much of the North American continent experienced drier than average conditions in March. Some exceptions are areas of the United States and a few isolated areas in Canada which received above average precipitation.

Global Surface Wetness

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Surface wetness was above average in portions of Europe, where excessive snow pack melted away. It was wetter than average in areas of northwest and southern Africa, central Argentina, and southern Australia. There were also many areas with below average wetness in March, such as a large portion of central China, the Ukraine, southern Russia, and southern Africa, where a drought has persisted for months.

These past few months, the snow cover has persisted longer than usual in the midwestern United States and western Russia. Water in its frozen state is not detected as surface wetness, i.e., liquid water, and therefore is indicated as a negative surface moisture anomaly. Sizable areas in northeastern Argentina, the Mideast, and northern Australia were drier than average this month.