Pdf Climate Prediction Center

ENSO Cycle: Recent
Evolution, Current
Status and Predictions
Update prepared by
Climate Prediction Center / NCEP
15 March 2010

Outline
• Overview
• Recent Evolution and Current Conditions
• Oceanic Niño Index (ONI) – “Revised December 2008”
• Pacific SST Outlook
• U.S. Seasonal Precipitation and
Temperature Outlooks
• Summary
• El Niño Composites

Summary
• El Niño is present across the equatorial Pacific Ocean.
• Sea surface temperatures (SST) are more than 1.0ºC above-average across much
of the central and eastern equatorial Pacific.
• Based on current observations and dynamical model forecasts, El Niño is
expected to continue at least through the Northern Hemisphere spring 2010.

Recent Evolution of Equatorial Pacific
SST Departures (oC)
Since the beginning of June 2009, SST
anomalies have been at least +0.5°C
across most of the equatorial Pacific.
Time
During December 2009, positive SST
anomalies increased across much of
the equatorial Pacific.
From late December 2009 to mid-
February 2010, positive SST anomalies
decreased across portions of the
central and east-central Pacific.
Recently, positive SST anomalies are
nearly unchanged across the central
and east-central Pacific.
Longitude

Niño Region SST Departures (oC)
Recent Evolution
The latest weekly SST departures are:
Niño 4
1.2ºC
Niño 3.4
1.2ºC
Niño 3
0.5ºC
Niño 1+2 -0.3ºC

SST Departures (oC) in the Tropical Pacific
During the Last 4 Weeks
During the last 4-weeks, equatorial SSTs were more than 1.0°C above average between
170°E and 125°W and near the western S. American coast.

Global SST Departures (oC)
During the last four weeks, equatorial SSTs were above-average across the central and
eastern Pacific, Indian, and Atlantic Oceans.

Weekly SST Departures (oC)
for the Last Four Weeks
• During the last four weeks, positive SST anomalies have
persisted across the central, east-central, and far eastern
Pacific.
• During the last 30 days, equatorial SST anomalies are
nearly unchanged across much of the Pacific, except for
an area of warming west of the Date Line.

Upper-Ocean Conditions in the Eq. Pacific
• The basin-wide equatorial upper
ocean (0-300 m) heat content is
greatest prior to and during the
Cold
early stages of a Pacific warm (El
Episodes
Niño) episode (compare top 2
Warm
panels) and least prior to and
Episodes
during the early stages of a cold (La
Niña) episode.
• The slope of the oceanic
thermocline is least (greatest)
during warm (cold) episodes.
• Recent values of the upper-ocean
heat anomalies (positive) and the
thermocline slope index (negative)
reflect El Niño.
The monthly thermocline slope index represents the difference in anomalous depth of the 20ºC
isotherm between the western Pacific (160ºE-150ºW) and the eastern Pacific (90º-140ºW).

Central & Eastern Pacific Upper-Ocean
(0-300 m) Weekly Heat Content Anomalies
Since April 2009, the upper-ocean heat content has been above average across
the eastern half of the equatorial Pacific Ocean. Sharp increases in heat content
during June and October 2009 coincide with the development and subsequent
strengthening of El Niño, respectively. During February 2010, heat content
anomalies increased again in association with an oceanic Kelvin wave.

Sub-Surface Temperature Departures (oC)
in the Equatorial Pacific
• In mid January 2010, positive subsurface
temperature anomalies increased in the
eastern equatorial Pacific in association with
the downwelling phase of an oceanic Kelvin
wave.
• Since mid-February 2010, the downwelling
phase of another oceanic Kelvin wave has
Time
increased temperatures in the east-central
equatorial Pacific Ocean.
Most recent pentad analysis
Longitude

Tropical OLR and Wind Anomalies
During the Last 30 Days
Large negative OLR anomalies (enhanced convection
and precipitation, blue shading) were located over
much of the central and eastern tropical Pacific
Ocean. Positive OLR anomalies (suppressed
convection and precipitation, red shading) were
located over most of the Maritime Continent,
northwestern Australia, and the Philippines.
Low-level (850-hPa) westerly anomalies were
observed over the central Pacific, south of the
equator. Another area of westerly anomalies was
evident in the eastern Pacific, centered north of the
equator.
Anomalous upper-level (200-hPa) easterly winds
were observed across the eastern equatorial
Pacific.

Atmospheric Circulation over the North Pacific & North
America During the Last 60 Days
200-hPa Wind
500-hPa Height & Anoms.
925-hPa Temp. Anoms. (oC)
During late January-February, strong mid-latitude westerlies (East Asian and Atlantic jets) were accompanied by troughs over
the eastern North Pacific and near the eastern U.S. The anomalous troughs were associated with below-average temperatures
over much of the central and eastern United States. At higher latitudes, strong ridging was associated with above-average
temperatures across most of Canada. Since late February, the flow across the N. Pacific has weakened, while the Atlantic jet
remains strong. This pattern has contributed to below-average temperatures across the southern U.S. while over Canada,
continued ridging has led to above-average temperatures.

U.S. Temperature and Precipitation Departures
During the Last 30 and 90 Days
Last 30 Days
30-day (ending 14 Mar 2010) % of
30-day (ending 13 Mar 2010)
average precipitation
temperature departures (degree C)
Last 90 Days
90-day (ending 14 Mar 2010) % of
90-day (ending 13 Mar 2010)
average precipitation
temperature departures (degree C)

Intraseasonal Variability
• Intraseasonal variability in the atmosphere (wind
and pressure), which is often related to the
Madden-Julian Oscillation (MJO), can
significantly impact surface and subsurface
conditions across the Pacific Ocean.
• Related to this activity
– significant weakening of the low-level easterly
winds usually initiates an eastward-propagating
oceanic Kelvin wave.
– Several Kelvin waves have occurred during the
last year (see next slide).

Weekly Heat Content Evolution
in the Equatorial Pacific
• In April 2009, the combined effects of an oceanic
Kelvin wave and weaker-than-average easterly
trade winds contributed to an increase in the
upper-ocean heat content anomalies across the
Pacific Ocean.
• Since April 2009, heat content anomalies have
remained above-average, but there has been
considerable month-to-month variability due to
Kelvin wave activity.
Time
• From November- January 2009, two oceanic
Kelvin waves contributed to the change in heat
down
content across the eastern half of the Pacific.
welling
• Since early February 2009, the heat content has
increased across the east-central Pacific in
association with the downwelling phase of another
Kelvin wave.
•Oceanic Kelvin waves have alternating warm and
cold phases. The warm phase is indicated by
dashed lines. Down-welling and warming occur in
the leading portion of a Kelvin wave, and up-
Longitude
welling and cooling occur in the trailing portion.

Low-level (850-hPa) Zonal (east-west)
Wind Anomalies (m s-1)
Westerly wind anomalies
(orange/red shading).
Easterly wind anomalies (blue
shading).
Since May 2009, westerly wind
anomalies have covered large portions
of the equatorial Pacific, except near
Time
the Date Line.
During November 2009, the MJO
became active, which contributed to
anomalous easterlies shifting eastward
from the Indian Ocean to the central
and eastern Pacific.
During February 2010, anomalous
low-level westerly winds strengthened
across the eastern half of the Pacific.
Recently, anomalous westerlies have
strengthened again across parts of the
Pacific.
Longitude

200-hPa Velocity Potential
Anomalies (5ºN-5ºS)
Positive anomalies (brown shading)
indicate unfavorable conditions for
precipitation.
Negative anomalies (green shading)
indicate favorable conditions for
precipitation.
During November, MJO activity was
Time
prevalent, but diminished during the
first half of December.
During July-October 2009 and since
December 2009, the anomalous velocity
potential pattern has generally featured
upper-level divergence over the west-
central Pacific (green) and upper-level
convergence (brown) over the eastern
Indian Ocean and Maritime Continent.
Longitude

Outgoing Longwave Radiation (OLR)
Anomalies
Drier-than-average conditions
(orange/red shading)
Wetter-than-average
conditions (blue shading)
Since mid-May 2009, convection has
remained mostly suppressed over the
eastern Indian Ocean and Maritime
Continent.
Time
The pattern of OLR anomalies since late
August 2009, generally featured
suppressed convection around 120ºE
and enhanced convection near the Date
Line. This pattern is consistent with El
Niño.
Periodic MJO activity has also been
evident in the eastward shift of OLR
anomalies.
Since mid-February, negative OLR
anomalies have become evident in the
eastern Pacific.
Longitude

Oceanic Niño Index (ONI)
• The ONI is based on SST departures from average in the
Niño 3.4 region, and is a principal measure for monitoring,
assessing, and predicting ENSO.
• Defined as the three-month running-mean SST departures
in the Niño 3.4 region. Departures are based on a set of
improved homogeneous historical SST analyses (Extended
Reconstructed SST – ERSST.v3b). The SST reconstruction
methodology is described in Smith et al., 2008, J. Climate,
vol. 21, 2283-2296.)
• Used to place current events into a historical perspective
• NOAA’s operational definitions of El Niño and La Niña are
keyed to the ONI index.

NOAA Operational Definitions for
El Niño and La Niña
El Niño: characterized by a positive ONI greater than or equal
to +0.5°C.
La Niña: characterized by a negative ONI less than or equal to
-0.5°C.
By historical standards, to be classified as a full-fledged El Niño
or La Niña episode, these thresholds must be exceeded for a
period of at least 5 consecutive overlapping 3-month seasons.
CPC considers El Niño or La Niña conditions to occur when the monthly
Niño3.4 SST departures meet or exceed +/- 0.5°C along with consistent
atmospheric features. These anomalies must also be forecasted to persist for 3
consecutive months.

ONI (oC): Evolution since 1950
The most recent ONI
value (December
2009 – February
2010) is +1.7oC.
El Niño
neutral
La Niña

Historical El Niño and La Niña Episodes
Based on the ONI computed using ERSST.v3b
Highest
Lowest
El Niño
ONI Value
La Nina
ONI Value
JAS 1951 - NDJ 1951/52 0.8
ASO 1949 – FMA 1951 -1.7
NOTE:
MAM 1957 – MJJ 1958 1.7
MAM 1954 – DJF 1956/57 -2.1
After updating the
ocean analysis to
JJA 1963 – DJF 1963/64 1.0
ASO 1962 − DJF 1962/63 -0.8
ERSST.v3b, a new La MJJ 1965 – MAM 1966 1.6
MAM 1964 – DJF 1964/65 -1.1
Niña episode was
OND 1968 – MJJ 1969 1.0
NDJ 1967/68 – MAM 1968 -0.9
classified (ASO 1962-
DJF 1962/63) and two
ASO 1969 – DJF 1969/70 0.8
JJA 1970 – DJF 1971/72 -1.3
previous La Niña
AMJ 1972 – FMA 1973 2.1
AMJ 1973 – MAM 1976 -2.0
episodes were
ASO 1976 – JFM 1977 0.8
SON 1984 – ASO 1985 -1.0
combined into one
ASO 1977 - DJF 1977/78 0.8
AMJ 1988 – AMJ 1989 -1.9
single episode (AMJ
1973- MAM 1976).
AMJ 1982 – MJJ 1983 2.3
ASO 1995 – FMA 1996 -0.7
JAS 1986 – JFM 1988 1.6
JJA 1998 – MJJ 2000 -1.6
AMJ 1991 – JJA 1992 1.8
SON 2000 – JFM 2001 -0.7
AMJ 1994 – FMA 1995 1.3
ASO 2007 – AMJ 2008 -1.4
AMJ 1997 – AMJ 1998 2.5
AMJ 2002 – FMA 2003 1.5
MJJ 2004 – JFM 2005 0.9
JAS 2006 - DJF 2006/07 1.1

Historical Pacific warm (red) and cold (blue) episodes based on a threshold of +/- 0.5 oC for
the Oceanic Nino Index (ONI) [3 month running mean of ERSST.v3b SST anomalies in the
Nino 3.4 region (5N-5S, 120-170W)], calculated with respect to the 1971-2000 base period.
For historical purposes El Niño and La Niña episodes are defined when the threshold is met
for a minimum of 5 consecutive over-lapping seasons.
Year
DJF
JFM
FMA
MAM
AMJ
MJJ
JJA
JAS
ASO
SON
OND
NDJ
1950
-1.7
-1.5
-1.3
-1.4
-1.3
-1.1
-0.8
-0.8
-0.8
-0.9
-0.9
-1.0
1951
-1.0
-0.9
-0.6
-0.3
-0.2
0.2
0.4
0.7
0.7
0.8
0.7
0.6
1952
0.3
0.1
0.1
0.2
0.1
-0.1
-0.3
-0.3
-0.2
-0.2
-0.1
0.0
1953
0.2
0.4
0.5
0.5
0.5
0.5
0.4
0.4
0.4
0.4
0.4
0.4
1954
0.5
0.3
-0.1
-0.5
-0.7
-0.7
-0.8
-1.0
-1.2
-1.1
-1.1
-1.1
1955
-1.0
-0.9
-0.9
-1.0
-1.0
-1.0
-1.0
-1.0
-1.4
-1.8
-2.0
-1.9
1956
-1.3
-0.9
-0.7
-0.6
-0.6
-0.6
-0.7
-0.8
-0.8
-0.9
-0.9
-0.8
1957
-0.5
-0.1
0.3
0.6
0.7
0.9
0.9
0.9
0.9
1.0
1.2
1.5
1958
1.7
1.5
1.2
0.8
0.6
0.5
0.3
0.1
0.0
0.0
0.2
0.4
1959
0.4
0.5
0.4
0.2
0.0
-0.2
-0.4
-0.5
-0.4
-0.3
-0.2
-0.2
1960
-0.3
-0.3
-0.3
-0.2
-0.2
-0.2
-0.1
0.0
-0.1
-0.2
-0.2
-0.2
1961
-0.2
-0.2
-0.2
-0.1
0.1
0.2
0.0
-0.3
-0.6
-0.6
-0.5
-0.4
1962
-0.4
-0.4
-0.4
-0.5
-0.4
-0.4
-0.3
-0.3
-0.5
-0.6
-0.7
-0.7
1963
-0.6
-0.3
0.0
0.1
0.1
0.3
0.6
0.8
0.9
0.9
1.0
1.0
1964
0.8
0.4
-0.1
-0.5
-0.8
-0.8
-0.9
-1.0
-1.1
-1.2
-1.2
-1.0
1965
-0.8
-0.4
-0.2
0.0
0.3
0.6
1.0
1.2
1.4
1.5
1.6
1.5
1966
1.2
1.0
0.8
0.5
0.2
0.2
0.2
0.0
-0.2
-0.2
-0.3
-0.3
1967
-0.4
-0.4
-0.6
-0.5
-0.3
0.0
0.0
-0.2
-0.4
-0.5
-0.4
-0.5
1968
-0.7
-0.9
-0.8
-0.7
-0.3
0.0
0.3
0.4
0.3
0.4
0.7
0.9
1969
1.0
1.0
0.9
0.7
0.6
0.5
0.4
0.4
0.6
0.7
0.8
0.7
1970
0.5
0.3
0.2
0.1
0.0
-0.3
-0.6
-0.8
-0.9
-0.8
-0.9
-1.1
1971
-1.3
-1.3
-1.1
-0.9
-0.8
-0.8
-0.8
-0.8
-0.8
-0.9
-1.0
-0.9
1972
-0.7
-0.4
0.0
0.2
0.5
0.8
1.0
1.3
1.5
1.8
2.0
2.1
1973
1.8
1.2
0.5
-0.1
-0.6
-0.9
-1.1
-1.3
-1.4
-1.7
-2.0
-2.1
1974
-1.9
-1.7
-1.3
-1.1
-0.9
-0.8
-0.6
-0.5
-0.5
-0.7
-0.9
-0.7
1975
-0.6
-0.6
-0.7
-0.8
-0.9
-1.1
-1.2
-1.3
-1.5
-1.6
-1.7
-1.7

Historical Pacific warm (red) and cold (blue) episodes based on a threshold of +/- 0.5 oC for
the Oceanic Nino Index (ONI) [3 month running mean of ERSST.v3b SST anomalies in the
Nino 3.4 region (5N-5S, 120-170W)], calculated with respect to the 1971-2000 base period.
For historical purposes El Niño and La Niña episodes are defined when the threshold is met
for a minimum of 5 consecutive over-lapping seasons.
Year
DJF
JFM
FMA
MAM
AMJ
MJJ
JJA
JAS
ASO
SON
OND
NDJ
1976
-1.6
-1.2
-0.8
-0.6
-0.5
-0.2
0.1
0.3
0.5
0.7
0.8
0.7
1977
0.6
0.5
0.2
0.2
0.2
0.4
0.4
0.4
0.5
0.6
0.7
0.7
1978
0.7
0.4
0.0
-0.3
-0.4
-0.4
-0.4
-0.4
-0.4
-0.3
-0.2
-0.1
1979
-0.1
0.0
0.1
0.1
0.1
-0.1
0.0
0.1
0.3
0.4
0.5
0.5
1980
0.5
0.3
0.2
0.2
0.3
0.3
0.2
0.0
-0.1
-0.1
0.0
-0.1
1981
-0.3
-0.5
-0.5
-0.4
-0.3
-0.3
-0.4
-0.4
-0.3
-0.2
-0.1
-0.1
1982
0.0
0.1
0.1
0.3
0.6
0.7
0.7
1.0
1.5
1.9
2.2
2.3
1983
2.3
2.0
1.5
1.2
1.0
0.6
0.2
-0.2
-0.6
-0.8
-0.9
-0.7
1984
-0.4
-0.2
-0.2
-0.3
-0.5
-0.4
-0.3
-0.2
-0.3
-0.6
-0.9
-1.1
1985
-0.9
-0.8
-0.7
-0.7
-0.7
-0.6
-0.5
-0.5
-0.5
-0.4
-0.3
-0.4
1986
-0.5
-0.4
-0.2
-0.2
-0.1
0.0
0.3
0.5
0.7
0.9
1.1
1.2
1987
1.2
1.3
1.2
1.1
1.0
1.2
1.4
1.6
1.6
1.5
1.3
1.1
1988
0.7
0.5
0.1
-0.2
-0.7
-1.2
-1.3
-1.2
-1.3
-1.6
-1.9
-1.9
1989
-1.7
-1.5
-1.1
-0.8
-0.6
-0.4
-0.3
-0.3
-0.3
-0.3
-0.2
-0.1
1990
0.1
0.2
0.2
0.2
0.2
0.2
0.3
0.3
0.3
0.3
0.3
0.4
1991
0.4
0.3
0.3
0.4
0.6
0.8
1.0
0.9
0.9
1.0
1.4
1.6
1992
1.8
1.6
1.5
1.4
1.2
0.8
0.5
0.2
0.0
-0.1
0.0
0.2
1993
0.3
0.4
0.6
0.7
0.8
0.7
0.4
0.4
0.4
0.4
0.3
0.2
1994
0.2
0.2
0.3
0.4
0.5
0.5
0.6
0.6
0.7
0.9
1.2
1.3
1995
1.2
0.9
0.7
0.4
0.3
0.2
0.0
-0.2
-0.5
-0.6
-0.7
-0.7
1996
-0.7
-0.7
-0.5
-0.3
-0.1
-0.1
0.0
-0.1
-0.1
-0.2
-0.3
-0.4
1997
-0.4
-0.3
0.0
0.4
0.8
1.3
1.7
2.0
2.2
2.4
2.5
2.5
1998
2.3
1.9
1.5
1.0
0.5
0.0
-0.5
-0.8
-1.0
-1.1
-1.3
-1.4
1999
-1.4
-1.2
-0.9
-0.8
-0.8
-0.8
-0.9
-0.9
-1.0
-1.1
-1.3
-1.6
2000
-1.6
-1.4
-1.0
-0.8
-0.6
-0.5
-0.4
-0.4
-0.4
-0.5
-0.6
-0.7
2001
-0.6
-0.5
-0.4
-0.2
-0.1
0.1
0.2
0.2
0.1
0.0
-0.1
-0.1

Pacific Niño 3.4 SST Outlook
• A majority of the models indicate that the Niño-3.4 temperature departures will gradually
decrease at least into the summer.
• The models are split with the majority indicating ENSO-neutral conditions by May-July 2010
and persisting into the Fall. Several models also suggest the potential of continued El Niño
conditions or the development of La Niña conditions during the Fall.
Figure provided by the
International Research
Institute (IRI) for
Climate and Society
(updated 16 Feb 2010).

SST Outlook: NCEP CFS Forecast
Issued 14 March 2010
The CFS ensemble mean (heavy blue line)
predicts El Niño will last through the
Northern Hemisphere spring 2010.
Please note the anomalies displayed above are not
PDF corrected (they are biased corrected).

U. S. Seasonal Outlooks
March – May 2010
Temperature
Precipitation
The seasonal outlooks combine the effects of long-term trends,
soil moisture, and, when appropriate, the ENSO cycle.

U.S. Precipitation Departures (mm)
and Frequency of Occurrence (%)
for El Niño during Jan.-Mar.
FREQUENCY (right panel) indicates the percentage of El Niño years that the indicated departure (left
panel) occurred. For example, below-average seasonal precipitation over Tennessee occurred in 80%-
90% of the El Niño years.

U.S. Temp. Departures (°C) and
Frequency of Occurrence (%)
for El Niño during Jan.-Mar.

U.S. Precipitation Departures (mm)
and Frequency of Occurrence (%)
for El Niño during Feb.-Apr.

U.S. Temp. Departures (°C) and
Frequency of Occurrence (%)
for El Niño during Feb.-Apr.

U.S. Precipitation Departures (mm)
and Frequency of Occurrence (%)
for El Niño during Mar.-May

U.S. Temp. Departures (°C) and
Frequency of Occurrence (%)
for El Niño during Mar.-May

U.S. Precipitation Departures (mm)
and Frequency of Occurrence (%)
for El Niño during Apr.-Jun.

U.S. Temp. Departures (°C) and
Frequency of Occurrence (%)
for El Niño during Apr.-Jun.

Document Outline

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