ENSO Cycle: Recent Evolution, Current Status and Predictions
The following UPDATE is prepared by
Climate Prediction Center / NCEP – 30 November 2009
The latest weekly SST departures are:
- Niño 4 ~ 1.6ºC
- Niño 3.4 ~ 1.7ºC
- Niño 3 ~ 1.3ºC
- Niño 1+2 ~ 0.2ºC
El Niño Map. [SOURCE: NOAA/ Climate Prediction Center / NCEP]
SST Departures (°C) in the Tropical Pacific During the Last 4 Weeks
During the last 4-weeks, SSTs were at least 1.0°C above average across much of the equatorial Pacific and more than 2.0°C above average between 180°and 130°W.
[SOURCE: NOAA/ Climate Prediction Center / NCEP]
Global SST Departures (°C)
During the last four weeks, equatorial SSTs were above-average across the Pacific and Indian Oceans. Also, above-average SSTs covered large areas of the Northern Hemisphere subtropics.
[SOURCE: NOAA/ Climate Prediction Center / NCEP]
Weekly SST Departures (°C) for the Last Four Weeks
- During the last four weeks, positive SST anomalies persisted across the central and eastern equatorial Pacific Ocean.
- During the last 30 days, equatorial SST anomalies increased in some parts across the eastern Pacific.
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Tropical OLR and Wind Anomalies During the Last 30 Days
TOP: Positive OLR anomalies (suppressed convection and precipitation, red shading) were present over Indonesia, Malaysia, Papua New Guinea, and Australia. Negative OLR anomalies (enhanced convection and precipitation, blue shading) were located over the western tropical Pacific Ocean just southeast of Papua New Guinea.
Middle: Low-level (850-hPa) westerly anomalies remained over the east-central equatorial Pacific.
Above: Upper-level (200-hPa) easterly anomalies were observed across the eastern equatorial Pacific. An anticycloniccouplet was evident in the subtropics of both hemispheres, which is consistent with El Niño.
Atmospheric Circulation over the North Pacific & North America During the Last 60 Days
During October, a nearly zonal pattern of below-average heights over the mid-latitudes was observed with an anomalous ridge over Alaska and the higher latitudes. This pattern contributed to below-average temperatures across Canada and much of the U.S. During November, the anomalous zonal pattern of below-average heights at mid-latitudes had been replaced by strong anomalous ridges across the N. Pacific and much of N. America with below-average heights across Alaska. This pattern has led to above-average temperatures across much of Canada and the United Statesand below-average temperatures in Alaska.
Intraseasonal Variability
- Intraseasonal variability in the atmosphere (wind and pressure), which is often related to the Madden-Julian Oscillation (MJO), can significantly impact surface and subsurface conditions across the Pacific Ocean.
- Related to this activity
- Significant weakening of the low-level easterly winds usually initiates an eastward-propagating oceanic Kelvin wave.
- Several Kelvin waves have occurred during the last year (see next slide).
Summary
- El Niño is present across the equatorial Pacific Ocean.
- Sea surface temperatures (SST) are at least 1.0ºC-2.0ºC 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 last through at least the Northern Hemisphere winter2009-10.
Information and images on this page are sourced from Climate Prediction Center/NCEP/NOAA. Edited by FEWW
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 Update [23 Nov 2009]
- El Niño Update [16 Nov 2009]
- El Niño Update [10 Nov 2009]
- El Niño Update [2 Nov 2009]
- El Niño [Main Page and Links Archive]
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