Synopsis: A transition to ENSO-neutral is likely during late Northern Hemisphere spring or early summer 2016, with close to a 50 percent chance for La Niña conditions to develop by the fall.
Sea surface temperature (SST) anomalies decreased across most of the central and eastern equatorial Pacific Ocean during February. The latest Niño-3.4 and Niño-3 weekly values were near 2°C, while the Niño-4 and Niño-1+2 indices were 1°C and 1.4°C respectively. The subsurface temperature anomalies in the central and eastern Pacific decreased substantially in association with the eastward shift of below-average temperatures at depth. Low-level westerly wind anomalies and upper-level easterly wind anomalies continued, but were weaker relative to January. The traditional and equatorial Southern Oscillation Index (SOI) remained strongly negative. In addition, convection was much enhanced over the central and east-central tropical Pacific and suppressed over parts of Indonesia and northern Australia. Collectively, these anomalies reflect the continuation of a strong El Niño.
All models indicate that El Niño will weaken, with a transition to ENSO-neutral likely during the late spring or early summer 2016. Thereafter, the chance of La Niña conditions increases into the fall. While there is both model and physical support for La Niña following a strong El Niño, considerable uncertainty remains. A transition to ENSO-neutral is likely during late Northern Hemisphere spring or early summer 2016, with close to a 50 percent chance for La Niña conditions to develop by the fall.
Most landmasses will experience average wind conditions for the month. Winds will be less than average in much of the central and western and southeastern Pacific Ocean into SE Asia and southern South America along with the Central Atlantic Ocean. Around New Zealand winds will be stronger than normal along the east coast as will the western South Pacific through to the far Southwest Pacific through the southern Philippines and the northwest Pacific and North Atlantic including and Eastern Europe and the UK.
Much of the northern hemisphere including Europe and the USA, Canada and Europe should be slightly to moderately below normal along with parts of Brazil. New Zealand and southern South America and the southwest Pacific and eastern Australia should be moderately below normal.
Cooler outbreaks are forecast for eastern north Asia and warm outbreaks in the Philippines and eastern China and the eastern Caribbean and northern Brazil and northern New Zealand. Much of the Canadian Northwest through to Alaska could have unusually high temperature outbreaks.
In the western hemisphere extreme precipitation events are forecast for Mexico, and the Southwest and across to Texas and parts of Southern California and parts of the northern and eastern Caribbean. The Amazon could have unusually to very unusually low rainfall.
In SE Asia and the South Pacific unusually low rainfall is forecast through the western 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 and isolated parts of west Asia. Dryness marks much of the Philippines and western Indonesia and Peninsular Malaysia and Sumatra.
Through much of Europe and Asia usual high to normal conditions prevail except in the UK where the risk of higher rainfall persists.
Usual high is forecast for parts of Southern Africa.
The slow evolution of ENSO to a more neutral situation can be viewed through sea surface temperature anomaly maps. The Eastern Pacific is still warmer than normal as is the Indian Ocean but less than previously forecast. The western and central Atlantic is also warmer than normal. The ocean surrounding New Zealand is warmer than normal to the east and north and warmer than normal around most of Australia with a warm pool expanding between Australia and Indonesia. The central 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.
Slightly wetter conditions prevail in much of the northern hemisphere with greater anomalies in the Pacific Northwest of the USA and the Caribbean and Southern Florida and through the Andes of South America and southern Brazil and Argentina and SE China while drier than normal conditions prevail through the Western and Southwest Pacific region. In the Southern hemisphere dryness is shown for Southern Africa, Madagascar and the Amazon basin and far southern Chile and the South Pacific islands. Wetter than normal conditions prevail in the northern quadrant of the South Pacific along the equator and into the Indonesian archipelago and the Northern Territory of Australia. Much of Europe and Eurasia is near normal to slightly wetter than normal.
Much of Canada down to the Gulf of Mexico are above normal for temperature while the western States of the USA and Mexico are cooler to considerably cooler than normal along with western Australia and Central Africa. 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. Part of southern China and northern SE Asia and far Northeast Asia are much colder than normal along with much of East Africa. Eastern Indonesia through Papua New Guinea and the South Pacific should be slightly cooler than normal. While most of the eastern half of Australia and New Zealand should be slightly to moderately above normal. Argentina and southern Brazil should be cooler than normal.