El Niño/La Niña Update (February 2017)

During the second half of 2016, tropical Pacific Ocean surface temperatures were at borderline weak La Niña/cool-neutral levels. Many atmospheric ENSO indicators also approached or exceeded La Niña thresholds. During January 2017, tropical Pacific Ocean temperatures and some atmospheric fields clearly returned to ENSO-neutral levels. With weak La Niña signals since mid-2016, in some regions the influence of other climate drivers may have equaled or even outweighed that of ENSO. Most of the climate models surveyed indicate neutral conditions will persist during the first half of 2017. Although there is a range of possibilities beyond May 2017, the re-emergence of La Niña appears the least likely scenario, with neutral ENSO conditions and El Niño both possible during the second half of 2017. National Meteorological and Hydrological Services will continue to closely monitor changes in the state of ENSO over the coming months.