El Niño conditions are likely to continue through March-May 2007
Published 16 years ago, updated 4 years ago
El Niño conditions are likely to continue through May 2007 reports the National Weather Service Climate Prediction Center.
Equatorial Pacific SST (surface and subsurface temperature) anomalies are near their peak and that decreasing anomalies are likely during February-May 2007. Recently observed trends in the upper ocean tend to support those forecasts. Decreasing upper-ocean heat content in the central equatorial Pacific has been progressing east in association with the upwelling portion of the most recent Kelvin wave (December 06). In the absence of any further Kelvin wave activity, the upper-ocean heat content should return to near average in a few months.
However, there is considerable uncertainty in this outlook, given the resurgence of MJO activity in late December 2006. MJO (Madden-Julian Oscillation) is an equatorial traveling pattern of anomalous rainfall that is planetary in scale. In the Pacific, strong MJO activity is often observed 6 – 12 months prior to the peaks of El Niño episodes.
It is possible that the enhanced precipitation phase of the MJO, which is currently entering the western tropical Pacific, might trigger a more persistent pattern of cloudiness and precipitation over the anomalously warm waters of the central equatorial Pacific during the next several weeks. If that occurs, then the equatorial easterlies over the central Pacific will likely weaken possibly leading to the initiation of a fifth Kelvin wave. For weekly updates on the latest conditions in the tropical Pacific: CPC El Nino page
There is an increased probability of observing El Niño-related effects over North America during January-March 2007, including warmer-than-average temperatures over western and central Canada, and over the 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 in portions of the Pacific Northwest. Global effects that can be expected during January-March include drier-than-average conditions over portions of Malaysia, Indonesia, northern and eastern Australia, some of the U.S.-affiliated islands in the tropical North Pacific, northern South America, and southeastern Africa, and wetter-than-average conditions over central South America and possibly along the coasts of Ecuador and northern Peru.