ENSO-neutral is favored (50 to ~55% chance) through the Northern
Hemisphere fall 2017.
During May, ENSO-neutral continued, though sea surface temperatures
(SSTs) were above average in the east-central Pacific Ocean
[Fig. 1]. The latest weekly Niņo index values were near +0.5°C in
most of the Niņo regions, except for the easternmost Niņo-1+2, which was
at +0.2°C
[Fig. 2]. The upper-ocean heat content anomaly increased during May
[Fig. 3], reflecting the expansion of above-average sub-surface
temperatures across the central and eastern Pacific
[Fig. 4] in association with a downwelling oceanic Kelvin wave.
While ocean temperatures were elevated, the atmosphere was close to
average. Atmospheric convection anomalies were weak over the central
tropical Pacific and Maritime Continent
[Fig. 5], while the lower-level and upper-level winds were near
average over most of the tropical Pacific. Both the Southern Oscillation
Index (SOI) and Equatorial SOI were also near zero. Overall, the ocean
and atmosphere system remains consistent with ENSO-neutral.
Many models predict the onset of El Niņo (3-month average Niņo-3.4 index
at or greater than 0.5°C) during the Northern Hemisphere summer
[Fig. 6]. However, the NCEP CFSv2 and most of the models from the
latest runs of the North American Multi-Model Ensemble (NMME) are now
favoring the continuation of ENSO-neutral. These predictions, combined
with the near-average atmospheric conditions over the Pacific, have
resulted in slightly more confidence for the persistence of ENSO-neutral
(50 to ~55% chance). However, chances for El Niņo remain elevated
(35-50%) relative to the long-term average into the fall. In summary,
ENSO-neutral is favored (50 to ~55% chance) through the Northern
Hemisphere fall 2017 (click
CPC/IRI consensus forecast for the chance of each outcome for each
3-month period).
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
Niņo/La Niņa Current Conditions and Expert Discussions). Forecasts
are also updated monthly in the
Forecast Forum of CPC's Climate Diagnostics Bulletin. Additional
perspectives and analysis are also available in an
ENSO blog.
The next ENSO Diagnostics Discussion is scheduled for 13 July 2017. 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
College Park, MD 20740
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