ENSO Cycle: Recent Evolution, Current Status and Predictions
The following UPDATE is prepared by
Climate Prediction Center / NCEP – 13 October 2009
The latest weekly SST departures are:
- Niño 4 ~ 1.0ºC
- Niño 3.4 ~ 0.7ºC
- Niño 3 ~ 0.7ºC
- Niño 1+2 ~ (-0.7)ºC
El Niño Map. [SOURCE: NOAA/ Climate Prediction Center / NCEP]
SST Departures (°C) in the Tropical Pacific During the Last 4 Weeks
WeeksDuring the last 4-weeks, equatorial SSTs were at least1.0°C above average across parts of the central and eastern Pacific.
Global SST Departures (°C)
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.
Weekly SST Departures (°C) for the Last Four Weeks
During the last four weeks, SST anomalies remained positive across the equatorial Pacific Ocean, except in the far eastern Pacific, which have become negative. •During the last month, equatorial SST anomalies decreased over much of the eastern Pacific and increased over the central Pacific.
Sub-Surface Temperature Departures (°C) in the Equatorial Pacific
Atmospheric Circulation over the North Pacific & North America During the Last 60 Days
During mid 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 the central U.S., which contributed to below-average temperatures in the region, while the northern U.S. and Canada remained warmer-than-average. Recently, an anomalous ridge has dominated the Gulf of Alaska, and a downstream trough has led tobelow-average temperatures across much of the western and northern U.S.
Pacific Niño 3.4 SST Outlook
Most ENSO models indicate El Niño will continue through the Northern Hemisphere winter 2009-10.
The models disagree on the eventual strength of El Niño (SST anomalies ranging from +0.5ºC to +2.0ºC), but a majority indicate at least a moderate strength El Niño (greater than +1.0°C) during November-December-January 2009-10.
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.
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:
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El Niño [Main Page and Archive]
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