Seasonal Highlights on the Climate System
'Seasonal Highlights' has been issued in PDF format since spring 2007 as a seasonal bulletin focusing on the seasonal highlights of the monitoring results. For monthly information, please refer to 'Monthly Highlights on the Climate System.'
Notice: From 19 May 2021 onward, the products in this page are based on the new climatological normal (1991-2020 average) unless otherwise stated.
Highlights in Summer (June 2021 - August 2021)
- Though ENSO-neutral conditions has persisted through the season (see El Niño Outlook updated on September 2021) negative SST anomalies were observed from the central to eastern part of the equatorial Pacific.
- In Japan seasonal precipitation amounts were significantly above normal on the Pacific side of eastern Japan and in western Japan, mainly due to active stationary fronts and moist wet-air inflow in August.
- Seasonal mean temperatures were extremely high from eastern part of Central Siberia to the northeastern part of East Asia, from southern Europe to the southwestern part of Northern Africa, and from the central to western part of North America.
- In the Indian Ocean, remarkably positive SST anomalies were observed south of Sumatra.
- Convective activity was enhanced from southwest of Sumatra to the Maritime Continent, over the seas south of Japan and the equatorial Atlantic, and suppressed over the Arabian Sea, from the Bay of Bengal to the Philippines and over the seas east of New Guinea.
- The convective activity over the Asian summer monsoon region was weaker than normal and the subtropical jet stream shifted southward from its normal position over Eurasia.
- The polar vortex in the Northern Hemisphere was stronger than normal and the polar front jet stream was clearly seen over northern Eurasia.
Full version (PDF)
The descriptions from Spring-2011 to Winter-2021 issue are based on the former climatological normal (1981-2010) unless otherwise stated.
In the descriptions until Winter-2011 issue, 1979-2004 average is used as climatological normal unless otherwise stated.
The descriptions until Autumn-2013 issue are based on the JRA-25/JCDAS datasets.
Figures and Tables
Tokyo Climate Center, Climate Prediction Division.
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