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
November 6, 2003

Equatorial surface and subsurface temperatures were warmer than average throughout most of the Pacific during October (Fig. 1 and Fig. 2, respectively). SST anomalies greater than +0.5°C (~1°F) were observed in most areas along the equator between Indonesia and the South American coast. By the end of the month, positive SST anomalies were observed in all of the Niņo regions (Fig. 3). However, the 850-hPa zonal wind indices (central and western equatorial Pacific values near zero), OLR index (near zero), 200-hPa zonal wind index (near zero), SOI and EQSOI (near zero) all indicate ENSO-neutral conditions. These indices do not show any significant trends that would support either additional large-scale increases or decreases of SST anomalies in equatorial Pacific.

A majority of the statistical and coupled model forecasts indicate near neutral conditions (Niņo 3.4 SST anomalies between -0.5°C and +0.5°C) for the remainder of 2003 and early 2004. However, over the past few months there has been a trend in the suite of forecasts towards somewhat warmer conditions, consistent with observed trends in SST anomalies. If the observed Nino 3.4 SST anomaly for October 2003 (+0.6°C) persists through November, the three-month (September-November) running mean value of this index would reach the NOAA threshold (+0.5°C) for El Niņo. Thus, it is likely that borderline El Niņo/ ENSO-neutral conditions will persist in the equatorial Pacific through the Northern Hemisphere winter of 2003-04. Further evolution of warm-episode conditions is possible if persistent enhanced equatorial convection (cloudiness and rainfall) develops in the vicinity of the date line (180°W), accompanied by weaker-than-average equatorial low-level easterly winds over the central and western Pacific.

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 temperature 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 CPC's Climate Diagnostics Bulletin Forecast Forum. 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