Skip Navigation Links 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center

CPC Search
About Us
   Our Mission
   Who We Are

Contact Us
   CPC Information
   CPC Web Team

HOME > Expert Assessments > ENSO Diagnostic Discussion
issued by
April 7, 2005
Spanish Version (Español -- Courtesy of INFOCLIMA, Peru)

Synopsis: A transition fromweak warm-episode (El Niņo conditions to ENSO-neutral conditions is expected to continue during the next three months.

Sea surface temperature  (SST) anomalies increased in the Niņo 3.4 and Niņo 3 regions during March 2005 (Fig. 1), while positive SST anomalies [greater than +0.5°C (~0.9°F)] persisted in the Niņo 4 region. By the end of the month, positive equatorial SST anomalies greater than +0.5°C (~0.9°F) extended from Indonesia eastward to 115°W (Fig. 2). Cloudiness and precipitation returned to near average over Indonesia , while the enhanced precipitation, observed over the central tropical Pacific in February, weakened and drier-than-average conditions developed over that region (Fig. 3).

The increase in SST anomalies and upper-ocean heat content (Fig. 4) in the east-central equatorial Pacific during the last half of March was associated with an eastward-propagating oceanic Kelvin wave (downwelling phase). This wave is stronger than those that have occurred in recent months in association with MJO activity. Surface and subsurface ocean temperatures are expected to increase along the west coast of South America (Ecuador and northern Peru) during April. However, substantial cooling in the upper ocean has occurred in the wake (upwelling phase) of this Kelvin wave, accompanied by a strengthening of the easterly winds over the central and western equatorial Pacific during March. This cooling is expected to propagate eastward, eventually reaching the eastern equatorial Pacific during May. Thus, the effects of the expected warming along the west coast of South America during April should be brief.

A majority of the statistical and coupled model forecasts indicate that a transition from weak warm- episode (El Niņo) conditions to ENSO-neutral conditions will continue during the next three months, and that ENSO-neutral conditions will likely prevail during the northern summer

This discussion is a consolidated effort of NOAA and its funded institutions. Weekly updates for SST, 850-hPa wind, OLR and features of the equatorial subsurface thermal structure are available on the Climate Prediction Center web page at (Weekly Update). Forecasts for the evolution of El Niņo/La Niņa are updated monthly in the Forecast Forum section of CPC's Climate Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled for 5 May 2005.  To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send your e-mail address to:

Climate Prediction Center
National Centers for Environmental Prediction
NOAA/National Weather Service
Camp Springs, MD 20746-4304

NOAA/ National Weather Service
National Centers for Environmental Prediction
Climate Prediction Center
5200 Auth Road
Camp Springs, Maryland 20746
Climate Prediction Center Web Team
Page last modified: July 10, 2003
Disclaimer Privacy Notice