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Synopsis:  El Niño conditions are likely to continue into early 2007.

Equatorial Pacific SST anomalies greater than +0.5ºC were observed in most of the equatorial Pacific, with anomalies exceeding +1.0ºC between 170ºE and 145ºW and between 130ºW and the South American coast (Fig. 1). The latest SST departures in the Niño regions are all near +1.0 (Fig. 2). Beginning in February the basin-wide upper ocean heat content increased, and since early April positive anomalies have been observed (Fig. 3). Since early July weaker-than-average low-level equatorial easterly winds have been observed across most of the equatorial Pacific. In October the Southern Oscillation Index (SOI) was negative for the sixth consecutive month. Collectively, these oceanic and atmospheric anomalies are consistent with the early stages of El Niño in the tropical Pacific.

Over the past several months most of the statistical and coupled model forecasts have trended towards warmer conditions in the tropical Pacific through the Northern Hemisphere winter. The latest NCEP climate forecast system (CFS) predictions indicate El Niño conditions for the remainder of 2006 and into the NH spring (SH fall) 2007 (Fig. 4). More than two-thirds of the other statistical and coupled model predictions also indicate El Niño conditions during the same period (Fig. 5).

Typical El Niño effects are likely to develop over North America during the upcoming winter season, including warmer-than-average temperatures over western and central Canada, and over the western and northern United States, wetter-than-average conditions over portions of the U.S. Gulf Coast and Florida, and drier-than-average conditions in the Ohio Valley and the Pacific Northwest. Global effects that can be expected during November-March include drier-than-average conditions over most of Malaysia, Indonesia, some of the U.S.-affiliated islands in the tropical North Pacific, northern South America and southeastern Africa, and wetter-than-average conditions over equatorial East Africa, central South America (Uruguay, northeastern Argentina, and southern Brazil) and along the coasts of Ecuador and northern Peru.

This discussion is a consolidated effort of NOAA and its funded institutions. Oceanic and atmospheric conditions are updated weekly  on the Climate Prediction Center website  (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts for the evolution of El Niño/La Niña are updated monthly in the Forecast Forum section of CPC's Climate Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled for 7 December 2006. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: ncep.list.enso-update@noaa.gov.