The canonical correlation analysis (CCA) forecast of
SST in the central Pacific (Barnett et al. 1988, Science, 241,
192‑196; Barnston and Ropelewski
1992, J. Climate, 5, 1316‑1345), is shown in Figs. F1 and F2. This forecast is produced routinely by the
Prediction Branch of the Climate Prediction Center. The
predictions from the National Centers for Environmental Prediction (NCEP)
Coupled Forecast System Model (CFS03) are presented in Figs. F3 and
F4a, F4b. Predictions from the
Markov model (Xue, et al. 2000: J. Climate, 13,
849‑871) are shown in Figs. F5 and F6. Predictions from the latest version of the
LDEO model (Chen et al. 2000: Geophys. Res.
Let., 27, 2585‑2587) are shown in Figs. F7
and F8. Predictions using linear inverse modeling (Penland and Magorian 1993: J.
Climate, 6, 1067‑1076) are shown in Figs. F9 and F10. Predictions from the Scripps / Max Planck
Institute (MPI) hybrid coupled model (Barnett et al. 1993: J. Climate, 6,
1545‑1566) are shown in Fig. F11.
Predictions from the ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea.
Forecasting, 12, 633‑652) are shown in Fig. F12. Niño 3.4 predictions are summarized in Fig.
F13, provided by the Forecasting and Prediction Research Group of the IRI.
The CPC and the contributors to the Forecast Forum caution
potential users of this predictive information that they can expect only modest
ENSO Alert System Status: El Niño Advisory
There is an approximately 70% chance that El Niño
will continue through Northern Hemisphere summer 2015, and a greater than 60%
chance it will last through autumn.
the end of March 2015, weak El Niño conditions were reflected by above-average
sea surface temperatures (SST) across the equatorial Pacific (Fig. T18) and by
the expected tropical atmospheric response. The monthly Niño indices
were +1.1°C in the Niño-4 region, +0.6°C in the Niño-3.4 region, and +0.2°C and
+0.1°C in the Niño-3 and Niño-1+2 regions, respectively (Table T2). Subsurface temperature anomalies increased
substantially during the month in response to a downwelling
oceanic Kelvin wave, which resulted in strong positive subsurface anomalies
across most of the Pacific (Fig. T17). Consistent with
ocean-atmosphere coupling, enhanced convection shifted eastward to the central
equatorial Pacific (Fig. T25), while low-level
westerly wind anomalies continued over the western equatorial Pacific and
upper-level easterly wind anomalies continued in the central Pacific (Figs.
T20, T21) Also, both the traditional
and the equatorial Southern Oscillation Index (EQSOI) remained negative during
the month (Figs. T1, T2). Collectively, these features reflect weak El Niño conditions.
Compared to last month,
more models predict El Niño (3-month values of the Niño-3.4 index equal to or
greater than 0.5°C) to continue throughout 2015 (Figs. F1-F13). These forecasts are
supported by the increase in subsurface temperatures, enhanced convection over
the Date Line, and the increased persistence of low-level westerly wind anomalies.
However, model forecast skill tends to be lower during the Northern Hemisphere
spring, which limits the forecast probabilities of El Niño through the year. At
this time, there is also considerable uncertainty as to how strong this event
may become. In summary, there is an approximately 70% chance that El Niño will
continue through the Northern Hemisphere summer 2015, and a greater than 60%
chance that it will last through autumn.
Weekly updates of oceanic
and atmospheric conditions are available on the Climate Prediction Center
Niño/La Niña Current Conditions and Expert Discussions).