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
expected to last at least into the Northern Hemisphere spring 2011.
Niña continued during October 2010, as indicated by below-average sea surface
temperatures (SSTs) across most of the equatorial Pacific Ocean (Fig. T18).
The Niño SST index values were between –1.3°C and
–1.9°C for the month (Table T2).
The subsurface heat content (average temperatures in the upper 300m of
the ocean) changed little during October, and remained well below-average in
association with a shallower-than-average thermocline across the central and
eastern Pacific (Fig. T17).
Convection remained enhanced over Indonesia and suppressed over the
western and central equatorial Pacific (Fig. T25).
This pattern was linked to a continuation of enhanced low-level easterly
trade winds and anomalous upper-level westerly winds over the western and
central equatorial Pacific (Figs. T20,
Collectively, these oceanic and atmospheric anomalies reflect the ongoing La Niña.
with nearly all ENSO forecast models (Figs. F1-F13), La Niña is expected to last at least into the
Northern Hemisphere spring 2011. A
large majority of models also predict La Niña to become a strong episode
(defined by a 3-month average Niño-3.4 index of –1.5°C or colder) by the
November-January season before gradually weakening.
A few of the models, including the NCEP Climate Forecast System (CFS),
suggest that La Niña could persist into the Northern Hemisphere summer 2011.
However, no particular outcome is favored beyond the Northern Hemisphere
spring due to large model disagreement and lower model skill during the period.
updates of oceanic and atmospheric conditions are available on the Climate
Niño/La Niña Current Conditions and Expert Discussions).