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Forecast Forum
DECEMBER 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: La
Niña Advisory
Outlook:
La Niña
is
expected to continue well into the Northern Hemisphere spring 2011.
Discussion:
A
moderate-to-strong La Niña continued during December 2010 as reflected by well
below-average sea surface temperatures (SSTs) across the equatorial Pacific
Ocean (Fig. T18).
The Niño SST index values were between –1.4°C to –1.6°C for the
month (Table T2). The
subsurface oceanic heat content (average temperatures in the upper 300m of the
ocean) continued to reflect a large reservoir of below-average temperatures at
depth in the central and eastern equatorial Pacific (Fig. T17).
Convection remained enhanced over Indonesia and suppressed over the
western and central equatorial Pacific (Fig. T25).
Also, enhanced low-level easterly trade winds and anomalous upper-level
westerly winds continued over the equatorial Pacific (Figs. T20,
T21). Collectively, these oceanic
and atmospheric anomalies reflect the ongoing La Niña.
The
current ENSO model forecasts have not changed significantly compared to last
month (Figs. F1-F13).
La Niña is currently near its peak and is expected to persist into the Northern
Hemisphere spring 2011 at a lesser intensity.
Thereafter, there remains considerable uncertainty as to whether La Niña
will last into the Northern Hemisphere summer (as suggested by the NCEP CFS and
a few other models), or whether there will be a transition to ENSO-neutral
conditions (as suggested by the CPC CON and a majority of the other models).
Weekly
updates of oceanic and atmospheric conditions are available on the Climate
Prediction
Center
homepage (El
Niño/La Niña Current Conditions and Expert Discussions).
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www.nws.noaa.gov
