Synopsis: El Niño is expected to remain strong through the Northern Hemisphere winter 2015-16, with a transition to ENSO-neutral anticipated during late spring or early summer 2016.
A strong El Niño continued during November as indicated by well above-average sea surface temperatures (SSTs) across the central and eastern equatorial Pacific Ocean. The Niño-4, Niño-3.4 and Niño-3 indices rose to their highest levels so far during this event, while the Niño-1+2 index remained approximately steady. The subsurface temperatures in the central and eastern Pacific, while still well above average, decreased slightly due to the eastward push of the upwelling phase of an equatorial oceanic Kelvin wave. Low-level westerly wind anomalies and upper-level easterly wind anomalies continued over the most of the tropical Pacific. The traditional and equatorial Southern Oscillation Index (SOI) values remained negative. These conditions are associated with enhanced convection over the central tropical Pacific and suppressed convection over Indonesia. Collectively, these atmospheric and oceanic anomalies reflect a strong El Niño episode that has matured.
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. The forecaster consensus remains nearly unchanged from last month, with the expectation that this El Niño will rank among the three strongest episodes as measured by the 3-month SST departures in the Niño 3.4 region dating back to 1950. El Niño is expected to remain strong through Northern Hemisphere winter 2015-16, with a transition to ENSO-neutral anticipated during the late spring or early summer 2016.
The entire region should be moderately to unusually warmer than normal especially mainland SE Asia.
Much of Mainland SE Asia should be near normal to slightly drier than normal except for Vietnam and southern Cambodia that should be moderately drier than normal even though these areas in contrast to the rest of the mainland tend to have a slightly wetter January. Peninsular Malaysia should also be moderately drier than normal while Singapore along with much of Indonesia and southern Borneo should be slightly to moderately wetter than normal while the Philippines and northern and eastern Borneo remains slightly to moderately drier than normal.
The entire region should be moderately to unusually warmer than normal especially mainland SE Asia.
Much of Mainland SE Asia should be near normal but this remains a rather dry month with 30 year averages still less than 30 mm for much of the subregion. Vietnam is still slightly drier than the rest of the mainland although from a higher base precipitation average. Dryness spreads from the Philippines to the south and west with more of the northern part of the Indonesian archipelago being drier than normal.