National Oceanic and Atmospheric Administration

National Climatic Data Center, 15 October 1999

• Climate of 1999: September Overview
• Detailed Climate Perspectives
  • Global Analysis
    
  • Global Regional Analyses
    
  • U.S. National Analysis
    
  • U.S. Regional/Statewide Analyses
    
  • Drought in the U.S.
    
  • Extreme Events
    
• 1999 Monthly Reports

The above figure shows September 1999 temperature anomalies calculated from available in-situ stations using a 1880 - 1998 base period. Two persistent high pressure areas, one over Europe and one over eastern Canada and the northeast U.S., resulted in temperatures well above the long term mean in these areas. (See the September atmospheric circulation pattern for the Northern Hemisphere.) Mean temperatures were more than 5 C above average in some locations. Above average temperatures were also recorded in the Far East, much of the southern half of South America, the Mediteranean and western areas of the United States. The largest area of cooler than average temperatures is shown throughout the central and southeastern areas of the U.S. No other area of widespread below average temperatures are shown in this figure; however, it is possible that cooler than average temperatures were more extensive, but not shown in this figure due to unreported data.

Temperature

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Preliminary mean monthly temperature anomalies (using a base period 1880-1998) for September are shown in the figure to the left. September 1999 ocean temperatures were much lower than the 1997 and 1998 values and were the 3rd coolest this decade. However, land temperature anomalies continued to be very warm. The average global land temperature was 0.65 C above the long term mean, the second warmest anomaly on record.

Precipitation

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As shown on the adjacent map, precipitation anomalies were highly variable in September. Flooding rains fell in northern areas of India and Bangladesh, while areas in the south and west were much drier than average. Eastern areas of the U.S. received record rainfall in September primarily due to hurricanes Dennis and Floyd. Areas to the west continued to be much drier than the long term mean. (See the U.S. national page for a complete discussion.)

Western Europe was wetter than average as a low pressure trough in the eastern Atlantic brought abundant moisture to Iceland and western areas of the European continent. An area of high pressure limited precipitation throughout much of eastern Europe. Tropical cyclones affected parts of Korea and southwestern Japan, producing much above average rainfall in these areas. For additional details on precipitation and temperatures in September see the Global Regional page .

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
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Asheville, NC 28801-5001
fax: 828-271-4876
phone: 828-271-4800
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For questions about this report, please contact:

David Easterling
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: David.Easterling@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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