Synopsis: El Niño will likely peak during the Northern Hemisphere winter 2015-16, with a transition to ENSO-neutral anticipated during the late spring or early summer 2016.
A strong El Niño continued during October as indicated by well above-average sea surface temperatures (SSTs) across the central and eastern equatorial Pacific Ocean. Most Niño indices increased during the month, although the far eastern Niño-1+2 index decreased, accentuating the maximum in anomalous SST farther west. The subsurface temperature anomalies also increased in the central and eastern Pacific, in association with another downwelling equatorial oceanic Kelvin wave. Low-level westerly wind anomalies and upper-level easterly wind anomalies continued over the western to east-central tropical Pacific. Also, the traditional and equatorial Southern Oscillation Index (SOI) values remained negative. These conditions are associated with enhanced convection over the central and eastern tropical Pacific and with suppressed convection over Indonesia. Collectively, these atmospheric and oceanic anomalies reflect a strong and mature El Niño episode.
Most models indicate that a strong El Niño will continue through the Northern Hemisphere winter 2015-16, followed by weakening and a transition to ENSO-neutral during the late spring or early summer (Fig. 6). The forecaster consensus remains nearly unchanged, with the expectation that this El Niño could rank among the top three strongest episodes as measured by the 3-month SST departures in the Niño 3.4 region going back to 1950. El Niño will likely peak during the Northern Hemisphere winter 2015-16, with a transition to ENSO-neutral anticipated during the late spring or early summer 2016.
Most landmasses will experience average wind conditions for the month. Winds will be less than average in much of the central and western Pacific Ocean and North Indian Ocean into SE Asia and across much of Africa and southern South America. Around New Zealand will be stronger than normal as will the western and north Pacific and Atlantic Oceans and Eastern Europe.
Much of the northern hemisphere including Europe and the USA, Canada and Europe should be near normal. Western Australia and Central Africa and southern South America and New Zealand should be slightly to moderately below normal. Indonesia and the Philippines and eastern Brazil and southwest Africa should be above normal.
Cool outbreaks are limited to Argentina, Uruguay and southern and far eastern Brazil, Central Africa and Northeast Asia. Meanwhile in the Pacific Ocean where the north Pacific through to the equatorial Pacific will be much warmer than normal as will be the eastern Pacific off of South America and the North Atlantic into Europe. While much of North Atlantic will be below normal the Atlantic along the USA eastern seaboard and to the east of the Caribbean will be warmer than normal. Southeast Asia will be warmer than normal.
In the western hemisphere extreme precipitation events are forecast for Mexico, Florida and the Bahamas and Argentina, Uruguay and Southern Brazil and isolated parts of Colombia, Ecuador and Peru while the Amazon could have unusually low rainfall.
In SE Asia and the South Pacific unusually low rainfall is forecast through the island portion of the region, In Northeast Asia unusually to very unusually high rainfall events are possible in much of China and also in Central Africa.
In Europe and Asia usual low to usual high conditions are forecast.
The evolution of ENSO can be viewed through sea surface temperature anomaly maps. The Eastern Pacific is warmer than normal as is the Indian Ocean. The western and central Atlantic is also warmer than normal. The ocean surrounding New Zealand is near normal and warmer than normal around most of Australia. The South Pacific remains cooler than normal and is related to ongoing rainfall deficits for the region. The sea in Northeast Asia is also considerably cooler than normal as well as in the northeast Canada while the artic sea is warmer than normal.
The Caribbean and coastal areas of the Pacific Northwest and Victoria Island in Canada show positive rainfall anomalies as well as western Colombia, Ecuador and Peru and northeastern Argentina, Uruguay and southeast Brazil. While elsewhere in the western hemisphere dry anomalies prevail in the Amazon basin and from southern Nicaragua through Panama.
I SE Asia and the South Pacific the archipelago of the Philippines and eastern Indonesia through Papua New Guinea and all the way southeast east through Fiji show a dry precipitation anomaly. East Asia, Sumatra and west through India and Sri Lanka show a modest to moderate wet precipitation anomaly. Australia has a positive anomaly while New Zealand is neutral. In Africa much of the continent is normal except for Central Africa which has a positive anomaly. Europe is largely normal except for the Scandinavian countries that have a modest to moderate positive anomaly. The rest of Asia is normal to slightly positive.
Much of Canada down to the Gulf of Mexico are above normal for temperature while the western States of the USA and Maritime Provinces of Canada are cooler to considerably cooler than normal. Central America and the Caribbean and the northern half of South America are above normal as is the Eastern half of Asia and most of Australia and Southeast Asia and India and southern part of the Middle East. Northeast and southern China is much colder than normal along with much of east Africa and the northern part of the Middle East. Eastern Indonesia through Papua New Guinea and the South Pacific should be slightly cooler than normal. While most of the western half of Australia and New Zealand should be slightly to moderately above normal along with New Zealand. Argentina and southern Brazil should be cooler than normal.