El Nino to bring drier-than-average conditions Feb-April

ANTARA News | February 6, 2010

Jakarta (ANTARA News) - El Nino`s expected impacts during February-April 2010 include drier-than-average conditions over Indonesia, according to the US Climate Prediction Center (CPC).

The CPC in its El Nino Advisory sent to ANTARA by e-mail on Friday said a significant El Nino persisted throughout the equatorial Pacific Ocean during January 2010.

Although sea surface temperature (SST) departures in the Nino-3.4 region decreased to +1.2 degree C in late January, SSTs continued to be sufficiently warm to support deep tropical convection.

Equatorial convection over the central Pacific remained enhanced during the month, while convection over Indonesia exhibited considerable week-to-week variability, according to the Maryland-based CPC.

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.

The latest Kelvin wave was associated with temperature departures exceeding +2 degrees C down to 150m depth across the eastern half of the equatorial Pacific.

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 Nino episode.

Nearly all models predict decreasing SST anomalies in the Nino-3.4 region through 2010, and model spread increases at longer lead times.

Nearly half of the models indicate the 3-month Nino-3.4 SST anomaly will drop below +0.5 degree C around April-May-June 2010, indicating a transition to ENSO (El Nino Southern Oscillation -neutral conditions during Northern Hemisphere spring. However, predicting the timing of this transition is highly uncertain.

El Nino 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.

For the contiguous United States, potential El Nino 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 Nino/La Ninaa Current Conditions and Expert Discussions).

Forecasts for the evolution of El Nino/La Nina 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.

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