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Forecast Forum
DECEMBER 2007
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.
Outlook:
La
Niņa is expected to continue into the Northern Hemisphere spring 2008.
Discussion:
La
Niņa remained at moderate strength during December 2007, with below-average sea
surface temperatures (SSTs) extending from 160šE to the South American coast (Fig.
T18). All of the Niņo region
indices remained cooler than −0.9°C (Table
T2), with the Niņo-3.4 and Niņo-3 indices persisting near −1.5°C.
The upper-ocean heat content (average temperatures in the upper 300 m of
the ocean) in the central and east-central equatorial Pacific remained below
average, with temperatures ranging from 2°C to 5°C below average at
thermocline depth (Fig. T17).
Consistent with these oceanic conditions, stronger-than-average low-level
easterly winds and upper-level westerly winds continued across the central
equatorial Pacific (Figs. T20 and T21),
convection remained suppressed throughout the central equatorial Pacific, and
slightly enhanced convection covered the far western Pacific (Fig.
T25). Collectively, these
oceanic and atmospheric conditions reflect a mature La Niņa.
The
recent SST forecasts (dynamical and statistical models) for the Niņo
3.4 region
indicate a continuation of La Niņa conditions into Northern Hemisphere spring
2008 (Figs. F1-F13). Over half of the models predict a moderate strength La Niņa
to continue through February-April, followed by weaker La Niņa conditions.
Current atmospheric and oceanic conditions and recent trends are consistent with
a likely continuation of La Niņa into the Northern Hemisphere spring 2008.
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
