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Use these links to access detailed analyses of the Global and U.S. climate of April 2001.
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| April was a very wet month across parts of western Alaska and the upper Midwest of the United States where precipitation totals locally exceeded 100 mm (3.94 inches) above average. Heavier than average precipitation also continued this month across much of western and central Europe. Precipitation deficits were common across the eastern and southern U.S., most of Australia, eastern Brazil as well as eastern China to Japan. A lack of significant rainfall again this month across parts of the Middle East continued to exacerbate severe drought conditions in Pakistan and Afghanistan. | 
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Temperatures measured in the lowest 8 km (5 miles) of the troposphere were 0.17°C (0.31°F) above the long term average (1979-1998). This was the 4th warmest April, but far below the record anomaly of 0.75°C (1.35°F) set during the strong El Niño of 1998. |
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Over the Northern Hemisphere, temperatures in April above the surface were also 4th warmest, with a positive departure of 0.28°C (0.50°F). Southern Hemisphere temperatures were near to the long term average, with temperatures averaging just 0.06°C (0.11°F) above the mean. In the lower stratosphere, the global temperature was 0.37°C (0.67°F) cooler than the average, which ranked as the 5th coolest April during the satellite period of record which began in 1979. This was the 8th consecutive April with below average stratospheric temperatures. Both the Northern and Southern Hemispheric temperatures were below the average, with departures of -0.45°C (-0.81°F) and -0.29°C (-0.52°F), respectively. Lower tropospheric and lower stratospheric temperature data are 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. |
| The Hovmüller diagram depicts sea surface temperatures in the equatorial eastern Pacific since the beginning of 1997. Large positive temperature anomalies (El Niño) developed late in 1997 and continued into 1998. Thereafter, La Niña conditions (cooler sea surface temperatures) have persisted. During the last few months, negative anomalies have decreased, suggesting a continued weakening of La Niña and a return toward more neutral conditions. | 
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For additional details on precipitation and temperatures in April see the Global Regional page .
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References:
Peterson, T.C. and R.S. Vose, 1997: An Overview of the Global Historical Climatology Network Database. Bull. Amer. Meteorol. Soc., 78, 2837-2849. For all climate questions other than questions concerning this report, please contact the National Climatic Data Center's Climate Services Division:
Climate Services Division
For questions about this report, please contact:
David Easterling-or- Jay Lawrimore
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http://www.ncdc.noaa.gov/oa/climate/research/2001/apr/global.html Downloaded Friday, 04-Jul-2008 20:45:55 EDT Last Updated Tuesday, 12-Jul-2005 09:59:19 EDT by Scott.Stephens@noaa.gov Please see the NCDC Contact Page if you have questions or comments. |
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