Monthly Highlights on the Climate System
'Monthly Highlights on the Climate System' has been issued in PDF format since March 2007 as a monthly bulletin focusing on the monthly highlights of the monitoring results.
Highlights in December 2017
- It is considered that La Niña conditions continue in the equatorial Pacific (see El Niño Outlook updated on 11 January 2018).
- Monthly mean temperatures were below normal all over Japan, especially in western Japan.
- onthly mean temperatures were extremely high from Alaska to the northeastern part of Eastern Siberia, from the southwestern USA to northwestern Mexico, and in southeastern Australia.
- Convective activity was enhanced from the South China Sea to the seas east of the Philippines.
- In the lower troposphere, cyclonic (anti-cyclonic) circulation anomalies straddling the equator were observed over the Maritime Continent (over the eastern Pacific).
- Monthly mean temperatures were extremely high from the western USA to central Mexico.
- In the 500-hPa height field, wave trains were clearly observed over northern Eurasia and the mid-latitudes in the Northern Hemisphere with positive (negative) anomalies over the western part of North America and southern China (the eastern part of North America and the eastern part of East Asia). The polar vortex in the Northern Hemisphere was weaker than normal.
Full version (PDF)
The descriptions until April 2011 are based on the old normal (i.e., the 1979 - 2004 average).
The descriptions until January 2014 are based on the JRA-25/JCDAS datasets.
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Tokyo Climate Center, Climate Prediction Division, 1-3-4 Otemachi, Chiyoda-ku, Tokyo, Japan.
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