Synopsis: El Niño is expected to continue at least into the Northern Hemisphere spring 2010.
A significant El Niño persisted throughout the equatorial Pacific Ocean during January 2010 (Fig. 1). Although sea surface temperature (SST) departures in the Niño-3.4 region decreased to +1.2oC in late January, SSTs continued to be sufficiently warm to support deep tropical convection (Fig. 2 and Fig. 3). Over the last several months, a series of oceanic Kelvin waves contributed to the build-up of heat content anomalies in the central and eastern Pacific (Fig. 4). The latest Kelvin wave was associated with temperature departures exceeding +2oC down to 150m depth across the eastern half of the equatorial Pacific (Fig. 5). Equatorial convection over the central Pacific remained enhanced during the month, while convection over Indonesia exhibited considerable week-to-week variability. While the low-level winds have been variable, low-level westerly and upper-level easterly wind anomalies generally prevailed during January. Collectively, these oceanic and atmospheric anomalies reflect a strong and mature El Niño episode.
Nearly all models predict decreasing SST anomalies in the Niño-3.4 region through 2010, and model spread increases at longer lead times (Fig. 6). Nearly half of the models indicate the 3-month Niño-3.4 SST anomaly will drop below +0.5oC around April-May-June 2010, indicating a transition to ENSO-neutral conditions during Northern Hemisphere spring. However, predicting the timing of this transition is highly uncertain.
El Niño impacts are expected to last into the Northern Hemisphere spring, even as equatorial SST departures decrease, partly due to the typical warming that occurs between now and April/May (Fig. 3). Expected impacts during February-April 2010 include drier-than-average conditions over Indonesia and enhanced convection over the central equatorial Pacific Ocean, which will likely expand eastward and influence portions of the eastern tropical Pacific, as well as coastal sections of Peru and Ecuador. For the contiguous United States, potential El Niño impacts include above-average precipitation for the southern tier of the country, with below-average precipitation in the Pacific Northwest and Ohio Valley. Below-average snowfall and above-average temperatures are most likely across the northern tier of states (excluding New England), while below-average temperatures are favored for the south-central and southeastern states.
This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web
site (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 4 March 2010. To receive
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