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IRI Climate Digest   November 2005

October Global Climate Summary

Climatological Background

During October, the Northern Hemisphere mid-latitude storm tracks increase in strength, while monsoon systems in West Africa, South Asia, and southwestern North America continue their retreat southward following the maximum solar heating. Late season tropical storm activity continues in the North Atlantic, the North Pacific and northern Indian Oceans. Spring is underway in the Southern Hemisphere, with mid-latitude storm tracks losing strength.

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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Above average temperatures dominated mid- to high-latitude land areas, with the October average more than 5C above the mean in the north-central Former Soviet Union. Elsewhere, temperatures remained well above average across most of western and southern Africa, Indonesia, Malaysia, and the Northern Territory and Queensland in Australia. The few regions of the globe exhibiting cooler-than-average conditions during October included northern Argentina, western Bolivia and the coastal areas of Peru and northern Chile, with the latter areas responding to below-average sea surface temperatures there.

Temperature Difference from the 1961-1990 mean, with data from NCEP Climate Prediction Center, CAMS.
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Precipitation was generally below average across southern Africa, marking a weak start to the rainy season there. Unusually dry conditions continued across much of central Brazil and northward into Colombia and Venezuela, and much of central and northern Europe were unusually dry for the month. Rainfall was well above average across eastern India into Bangladesh, western Indonesia and Malaysia, and Vietnam. Record rainfall was recorded in several locations in the northeastern United States during October.

Precipitation Difference from 1979-2000 mean, with data from NCEP Climate Prediction Center, CAMS-OPI.
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Oceanic Conditions

Tropical sea surface temperatures (SSTs) exhibited little change from those in September, with a tendency for slightly below-average temperatures in the eastern tropical Pacific. SSTs in the western tropical Atlantic Ocean remained much higher than average, and contributed to an active Atlantic hurricane season. SSTs continued to be warmer-than-average across the western tropical Pacific and the equatorial regions of the Indian Ocean.

Outside of the tropics, SSTs were above average across the central North Pacific and northern North Atlantic in October, while below-average ocean surface temperatures continued across the mid-latitude south-central Indian Ocean.

Monthly Sea Surface Temperature Difference from the 1971-2000 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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