El Niño Update [14 Sept 2009]

ENSO Cycle: Recent Evolution, Current Status and Predictions

The following UPDATE is prepared by

Climate Prediction Center / NCEP – 14 Sept 2009

The latest weekly SST departures are:

• Niño 4   ~ 0.8ºC
• Niño 3.4  ~ 0.9ºC
• Niño 3 ~ 0.8ºC
• Niño 1+2 ~ 0.5ºC

El Niño Map. [SOURCE: NOAA/ Climate Prediction Center / NCEP]

Niño Region SST Departures (ºC) –  Recent Evolution

Weekly SST Departures (ºC) for the Last Four Weeks

• During the last four weeks, SST anomalies have increased in some areas of the equatorial Pacific Ocean.
• During the last month, the change in equatorial SST

Central & Eastern Pacific Upper-Ocean (0-300 m) Weekly Heat Content Anomalies
Since April 2009, the upper-ocean heat content has been above average across the eastern half of the equatorial Pacific Ocean. The heat content was previously below-average from mid-August 2008 through March 2009, with a minimum reached in late December 2008.

Weekly Heat Content Evolution in the Equatorial Pacific

1. During September 2008 –January 2009, negative heat content anomalies returned and then strengthened in the central and eastern equatorial Pacific as La Niña conditions redeveloped.

2. The negative anomalies weakened during January-March 2009, with anomalies becoming positive since late March.

In April 2009, the combined effects of an oceanic Kelvin wave and weaker easterly trade winds contributed to an increase in the upper-ocean heat content anomalies across the Pacific Ocean.

Since April 2009, heat content anomalies have remained above-average.

3. Recently, the downwelling phase of a Kelvin wave has shifted eastward.

Oceanic Kelvin waves have alternating warm and cold phases. The warm phase is indicated by dashed lines. Down-welling and warming occur in the leading portion of a Kelvin wave, and up-welling and cooling occur in the trailing portion.

SST Outlook: NCEP CFS Forecast Issued 13 September 2009
El Niño will last through Northern Hemisphere winter 2009-10.

Summary

• El Niño is present across the equatorial Pacific Ocean.

• Sea surface temperatures (SST) remain +0.5 to +1.5ºC above-average across much of the equatorial Pacific Ocean.

• Based on current observations and dynamical model forecasts, El Niño is expected to strengthen and last through Northern Hemisphere winter 2009-10.

Information and images on this page are sourced from Climate Prediction Center/NCEP/NOAA.

For additional information see following links.

Relate Links:

• Recognizing El Niño
• El Niño and La Niña: Tracing the Dance of Ocean and Atmosphere
• TAO Diagrams
• El Niño Forecasts

El Niño Updates

• El Niño Update [31 Aug 2009]
• El Niño Update [17 Aug 2009]
• El Niño Update – 10 August 2009
• El Niño Update – 3 August 2009
• El Niño Update – 27 July 2009

• El Niño Update – 20 July 2009
• El Niño Update # 1
• El Niño conditions is in progress —NOAA
• El Niño event almost certain: BOM
• El Niño could develop June – August 2009
• World Now
• 2009 Hurricane Season