CPC and the contributors to the Forecast Forum caution potential users of
this predictive information that they can expect only modest skill.
Alert System Status: La Niņa Advisory
transition to ENSO-neutral conditions is expected during April 2009.
and oceanic conditions during March 2009 continued to reflect weak La Niņa
conditions. The monthly sea surface temperatures (SST) remain below-average
across parts of the east-central and eastern
The Niņo-3.4 SST index value was −0.6°C for the month (Table
T2). Negative subsurface oceanic
heat content anomalies (average temperatures in the upper 300m of the ocean)
weakened further across the eastern half of the equatorial
At thermocline depth, positive temperature anomalies in the western and
central Pacific expanded eastward, while negative temperature anomalies became
confined to the far eastern Pacific (Fig. T17).
Convection remained suppressed near the Date Line, and enhanced across
, but weakened during
the later part of the month due to Madden-Julian Oscillation (MJO) activity (Fig.
Enhanced low-level easterly winds and upper-level westerly winds also
decreased across the equatorial
Collectively, these oceanic and atmospheric anomalies are consistent with a
weakening La Niņa.
majority of model forecasts for the Niņo-3.4 region show that once established,
ENSO-neutral conditions will continue through the remainder of 2009.
Several models indicate La Niņa will continue through March-May 2009 (Figs.
F1-F13). Based on current observations, recent trends, and
model forecasts, a transition to ENSO-neutral conditions is expected during
updates of oceanic and atmospheric conditions are available on the Climate
Niņo/La Niņa Current Conditions and Expert Discussions).