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.
ENSO events typically translate to drier than normal conditions in India.
Much of the northern half of the central part of the country should be 1.0 to 1.5 degrees C above normal. With just slightly warmer than normal conditions are expected in West Bengal and Jharkhand and the far eastern states of Nagaland and Arunchal Pradesh.
Much of the western two-thirds of the country should be 1.0 to 1.5 degrees C above normal. From New Delhi east through West Bengal and to Nagaland and Arunchal Pradesh temperatures should be closer to normal.
Much of the central, south and western half of the country should be slightly to moderately drier than normal but this is historically a very dry month as shown in the long term normal for January. Just the far northwest including Jammu & Kashmir, western Punjab and eastern Rajasthan and northeast from central Uttar Pradesh east through northern Bihar and the far north of the northeast should be moderately wetter than normal although the monthly averages area only in the 30 to 40 mm range for much of this region other than the Himalayas. Interestingly, Tamil Nadu and Andhra Pradesh and part of Karnataka and southern Maharashtra should be slightly wetter than normal however this is from a reasonably dry historical monthly average but it is a change in forecast from two weeks ago.
Much of the country should be near normal. This is a relatively dry month for much of the country and anomalies are only slightly wetter for the far southeast and northeast and northwest and through Rajasthan and eastern and coastal Maharashtra although this is not significant as it is an historically very dry month.