El Niño Update [21 Sept 2009]

ENSO Cycle: Recent Evolution, Current Status and Predictions

The following UPDATE is prepared by

Climate Prediction Center / NCEP – 21 Sept 2009

The latest weekly SST departures are:

• Niño 4   ~ 0.8ºC
• Niño 3.4  ~ 0.9ºC
• Niño 3 ~ 0.8ºC
• Niño 1+2 ~ 0.3ºC

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

Niño Region SST Departures (ºC) –  Recent Evolution

Highlights

During the last 4-weeks, equatorial SSTs were at least1.0°C above average across much of the central and eastern equatorial Pacific.

Global SST Departures  (ºC)
During the last four weeks, equatorial SSTs were above-average in the Pacific and Indian Oceans. Also, above-average SSTs covered large areas of the Northern Hemisphere mid-to-high latitudes.

Weekly SST Departures (ºC) for the Last Four Weeks
During the last four weeks, SST anomalies have remained positive across the equatorial Pacific Ocean. •During the last month, the change in equatorial SST anomalies was slightly positive in the east-central Pacific.

Atmospheric Circulation over the North Pacific & North America During the Last 60 Days
During late July through mid-September, an anomalous trough was prevalent in the central North Pacific Ocean. Downstream over the United States, the anomalous height pattern generally featured a trough over the eastern United States with ridging prevalent over the western U.S. This anomalous pattern led to below-average temperatures over the central and eastern U.S. and to above-average temperatures over portions of the western U.S.

ONI Evolution
The most recent ONI value (June –August 2009) is +0.7oC.

Pacific Niño 3.4 SST Outlook

• Most ENSO models indicate El Niño will continue through Northern Hemisphere winter 2009-10.
• The models disagree on the eventual strength of El Niño (SST anomalies ranging from +0.5°C to +2.0°C), but a majority indicate at least a moderate strength El Niño (greater than +1.0°C) during November-December-January 2009-10.

Figure provided by the International Research Institute (IRI) for Climate and Society (updated 14 Sept 2009).

SST Outlook: NCEP CFS Forecast Issued 20 September 2009
The CFS ensemble mean predicts 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.

Related 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 [Main Page]

• El Niño Update [14 Sept 2009]
• El Niño Update [8 Sept 2009]
• 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

Climate Prediction, El Niño weekly report, Global SST anomalies, Oceanic Kelvin waves, equatorial Pacific Ocean.