A transition to ENSO-neutral is expected to occur by February 2017,
with ENSO-neutral then continuing through the first half of 2017.
La Niņa continued during December, with negative sea surface temperature
(SST) anomalies continuing across the central and eastern equatorial
Pacific
[Fig. 1]. The weekly Niņo index values fluctuated during the last
month, with the Niņo-3 and Niņo-3.4 regions hovering near and slightly
warmer than -0.5°C
[Fig. 2]. The upper-ocean heat content anomaly was near zero when
averaged across the eastern Pacific
[Fig. 3], though near-to-below average subsurface temperatures were
evident closer to the surface
[Fig. 4]. Atmospheric convection remained suppressed over the
central tropical Pacific and enhanced over Indonesia
[Fig. 5]. The low-level easterly winds were slightly enhanced over
the western Pacific, and upper-level westerly anomalies were observed
across the eastern Pacific. Overall, the ocean and atmosphere system
remained consistent with a weak La Niņa.
The multi-model averages favor an imminent transition to ENSO-neutral
(3-month average Niņo-3.4 index between -0.5°C and 0.5°C), with
ENSO-neutral lasting through August-October (ASO) 2017
[Fig. 6]. Along with the model forecasts, the decay of the
subsurface temperature anomalies and marginally cool conditions at and
near the ocean surface portends the return of ENSO-neutral over the next
month. In summary, a transition to ENSO-neutral is expected to occur by
February 2017, with ENSO-neutral then continuing through the first half
of 2017 (click
CPC/IRI consensus forecast for the chance of each outcome for each
3-month period).
Even as the tropical Pacific Ocean returns to ENSO-neutral conditions,
the atmospheric impacts from La Niņa could persist during the upcoming
months (NOAA's
3-month seasonal outlook will be updated on Thursday, January 19th).
The current seasonal outlook for JFM 2017 favors above-average
temperatures and below-median precipitation across much of the southern
tier of the U.S., and below-average temperatures and above-median
precipitation in portions of the northern tier of the U.S.
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 09 February 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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