El Niño Update [5 Oct 2009]

ENSO Cycle: Recent Evolution, Current Status and Predictions

The following UPDATE is prepared by

Climate Prediction Center / NCEP –  5 Oct 2009

The latest weekly SST departures are:

• Niño 4   ~ 0.8ºC
• Niño 3.4  ~ 0.7ºC
• Niño 3 ~ 0.6ºC
• Niño 1+2 ~ -0.3ºC

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

Highlights

SST Departures (ºC) in the Tropical Pacific During the Last 4 Weeks
During the last 4-weeks, equatorial SSTs were at least1.0°C above average across parts of the central and eastern 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 subtropics and mid-latitudes.

Weekly SST Departures (ºC) for the Last Four Weeks

• During the last four weeks, SST anomalies remained positive across the equatorial Pacific Ocean.
• During the last month, SST anomalies decreased over the eastern equatorial SST.

Sub-Surface Temperature Departures (ºC) in the Equatorial Pacific

Atmospheric Circulation over the North Pacific & North America During the Last 60 Days
During early August through September, an anomalous trough was prevalent in the North Pacific Ocean/Gulf of Alaska. During September, an anomalous ridge was present downstream, focused over Canada and the northern United States. The pattern also featured a weak trough over thecentral U.S., which contributed to cooling in the region, while the northern U.S. and Canada remained warmer-than-average.

The most recent ONI value (July –September 2009) is +0.8oC.

Summary

• El Niño is present across the equatorial Pacific Ocean.
• Sea surface temperatures (SST) were at least 1.0ºC above-average across much of the central and east-central equatorial Pacific.
• Based on current observations and dynamical model forecasts, El Niño is expected to strengthen and last through Northern Hemisphere winter 2009-10.

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 [28 Sept 2009]
• El Niño Update [21 Sept 2009]

• 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