November 2018 Climate Forecast Discussion for Dec-Feb 2018 through Mar-May 2019
The SST forecast shows moderate El Nino conditions (>1.0ºC and <1.5ºC for the Nino3.4 SST index) during Dec-Feb and Jan-Mar, becoming weak (>0.5ºC and <1.0ºC) for Feb-Apr and Mar-May. Much of the extratropical North Atlantic and North Pacific SSTs, as well as the SSTs in much of the subtropical South Indian and high-latitude South Pacific oceans, are predicted to be above-average during all four forecast seasons. Exceptions are noted in the very high latitudes just south of Greenland and along 60ºS, where below-average SST is predicted during Dec-Feb and Jan-Mar for the latter, and all four seasons for the former. Slightly below-average SST is also predicted in the southeast tropical Pacific for the Dec-Feb season. A positive Indian Ocean Dipole is predicted for all four forecast seasons. and above-average SST is predicted for the north and south tropical Atlantic for all four forecast seasons.
A tilt of the odds toward below-normal precipitation is forecast for Indonesia, the Philippines, variable parts of northern South America and mainly northern and western Australia for all four forecast seasons (Dec-Feb through Mar-May). Enhanced probabilities for below-normal precipitation are also predicted for parts of southwestern Africa, parts of coastal southeast Asia and central Chile for Feb-Apr and Mar-May. Enhanced chances for above-normal precipitation are forecast for part of southeastern South America, parts of the southern U.S. and/or northern Mexico, and varying parts of Asia for most or all of the four forecast seasons. Above-normal is also favored for the northern part of eastern equatorial Africa and northeastern Greenland for Dec-Feb.
Enhanced probabilities for above-normal temperature are predicted for Greenland, and varying parts of Australia, Asia, Africa, North America and South America, and mainly non-western Europe from Dec-Feb through Mar-May. For most of the forecast seasons, the above-normal signal is weak or absent in the southern one-third of South America, southeastern U.S., south-central and far northern Africa. Enhanced probabilities for below-normal temperature are very scant, and appear weakly in part of central North America in Dec-Feb and part of central Asia in Jan-Mar. An enhanced likelihood for near-normal temperature is predicted for various parts of northern South America, tropical Africa, and Indonesia in most or all of the four forecast seasons.
