conditions are expected to continue during the next 1-3 months.
The patterns of anomalous ocean temperatures,
atmospheric circulation and precipitation are consistent in indicating La Niña
conditions in the tropical Pacific.
During March negative equatorial SST anomalies less than –0.5ºC were
observed at most locations between 180ºW and 90ºW (Fig.
1), and negative SST departures were observed in all of the Niño
regions, except for Niño 1+2 (Fig. 2). During the month, positive SST
departures decreased in the extreme eastern equatorial Pacific, as conditions
returned to near average in that region.
March above-average precipitation (negative OLR anomalies, Fig.
3, top panel)
was observed over Indonesia, the Philippines, northern Australia and
Hawaii, while below-average precipitation (positive OLR anomalies) was observed
over the central equatorial Pacific and over the eastern tropical Pacific
between the equator and 10ºN. Stronger-than-average low-level (850-hPa)
easterly winds (Fig. 3, middle panel) persisted over the central equatorial
Pacific, and anomalous upper-level (200-hPa) cyclonic circulation centers
were observed in both hemispheres (Fig. 3, bottom panel). The equatorial
subsurface temperature anomaly pattern (negative anomalies in the central and
eastern Pacific and positive anomalies in the western Pacific, Fig.
persisted during February-March 2006, and the basin-wide upper ocean heat
content, although increasing, remained below-average (Fig.
atmospheric and oceanic features are consistent with ongoing La Niña
Most of the statistical and coupled model forecasts indicate ENSO-neutral conditions
in the tropical Pacific through the end of 2006 (Fig. 6). The spread of the most
recent statistical and coupled model forecasts (weak La Niña
to weak El Niño) indicates uncertainty in the outlooks for the last half of
the year. However,
current conditions (stronger-than-average easterly winds over the central
equatorial Pacific and below-average upper-ocean heat content) support those
forecasts indicating that La Nina conditions will continue for the next 1-3
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 http://www.cpc.ncep.noaa.gov (Weekly Update). Forecasts for the evolution of El Niño/La Niña are updated monthly in the
Forecast Forum section of CPC's Climate
Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled for
May 2006. To receive
an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail