ENSO-neutral is favored into the Northern Hemisphere summer 2013
During February 2013, ENSO-neutral continued although SSTs remained
below average across the eastern half of the equatorial Pacific Ocean (Fig.
1). The Niño 3.4 index remained near -0.5oC, while the Niño 3 index
became less negative as the month progressed (Fig.
2). The oceanic heat content (average temperature in the upper 300m
of the ocean) similarly increased during the month (Fig.
3), largely due to the eastward push of above-average temperatures
at depth (Fig.
4). The Madden-Julian Oscillation (MJO) again contributed to
increased atmospheric variability over the tropical Pacific during
February. Anomalous low-level winds were primarily easterly over the
west-central equatorial Pacific, while upper-level winds remained near
average, but with some intra-monthly variability. Over Indonesia,
anomalous convection remained enhanced north of the equator and
suppressed south of the equator (Fig.
5). Due to the lack of persistent atmosphere-ocean coupling, the
tropical Pacific continues to reflect ENSO-neutral.
Most models forecast Niño-3.4 SSTs to remain between 0oC and -0.5oC
through Northern Hemisphere spring and to remain ENSO-neutral (between
-0.5oC and +0.5oC) into the fall (Fig.
6). However, there is increasing model spread and overall less
confidence in the forecast during the last half of the year, partly
because of the so-called “spring barrier,” which historically leads to
lower model skill beginning in late spring. Thus, ENSO-neutral is
favored into the Northern Hemisphere summer 2013 (see
CPC/IRI consensus forecast).
This discussion is a consolidated effort of the National Oceanic and
Atmospheric Administration (NOAA), NOAA's National Weather Service, and
their funded institutions. Oceanic and atmospheric conditions are
updated weekly on the Climate Prediction Center web site (El
Niño/La Niña Current Conditions and Expert Discussions). Forecasts
for the evolution of El Niño/La Niña are updated monthly in the
Forecast Forum section of CPC's Climate Diagnostics Bulletin. The
next ENSO Diagnostics Discussion is scheduled for 4 April 2013. To
receive an e-mail notification when the monthly ENSO Diagnostic
Discussions are released, please send an e-mail message to:
ncep.list.enso-update@noaa.gov.
Climate Prediction Center
National Centers for Environmental Prediction
NOAA/National Weather Service
Camp Springs, MD 20746-4304
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html
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