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Forecast Forum
MARCH 2010
Forecast Forum
The
CPC and the contributors to the Forecast Forum caution potential users of
this predictive information that they can expect only modest skill.
ENSO
Alert System Status: El
Niņo Advisory
Outlook:
El Niņo is expected to
continue through the Northern Hemisphere Spring 2010 and transition to ENSO-neutral conditions by
Northern Hemisphere summer 2010.
Discussion:
El
Niņo weakened to moderate strength during March 2010, with sea surface
temperature (SST) anomalies decreasing slightly, but still exceeding +1°C
across much of the central and eastern equatorial Pacific Ocean at the end of
the month (Fig. T18, Table T2).
Subsurface heat content anomalies (average temperatures in the upper 300m
of the ocean) decreased during March in response to the eastward expansion of
below-average temperature anomalies at depth (100-200m) into the east-central
Pacific (Fig. T17).
Anomalous tropical convection remained consistent with El Niņo, with
enhanced convection over the central and eastern Pacific and suppressed
convection over Indonesia (Fig. T25).
The equatorial low-level easterly trade winds strengthened near the Date
Line, while upper-level easterly wind anomalies became confined to the eastern
Pacific (Figs. T20, T21).
Collectively, these oceanic and atmospheric anomalies reflect an ongoing,
but weakening El Niņo.
Nearly
all models predict decreasing SST anomalies in the Niņo-3.4 region through
2010, with the model spread increasing at longer lead times (Figs.
F1-F13).
The majority of models predict the 3-month Niņo-3.4 SST anomaly will
drop below +0.5°C by May-June-July 2010, indicating a transition to ENSO-neutral
conditions that will likely persist through Northern Hemisphere summer.
Over the last couple months, an increasing number of models, including
the latest runs from the NCEP Climate Forecast System (CFS), are predicting
below-average temperatures in the Niņo-3.4 region by Northern Hemisphere fall,
with some forecasts meeting thresholds for La Niņa.
However, it should be noted that model skill is at a minimum during this
time of year, and also that the majority of models continue to indicate the
persistence of ENSO-neutral conditions through 2010.
Weekly
updates of oceanic and atmospheric conditions are available on the Climate
Prediction
Center
homepage (El
Niņo/La Niņa Current Conditions and Expert Discussions).
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www.nws.noaa.gov
