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: La Niña Advisory
Niña is expected to transition to ENSO-neutral during April-May, with ENSO-neutral
then likely (greater than 50% chance) to continue through the Northern
Hemisphere summer 2018.
March 2018, La Niña continued to weaken, but was still reflected by
below-average sea surface temperatures (SSTs) across the east-central and
eastern equatorial Pacific Ocean (Fig. T18). The latest monthly index values
were -0.7°C and -0.8°C in the Niño-3.4
and Niño-3 regions, respectively, -0.8°C in the Niño1+2 region, and near zero in the Niño.4 region (Table T2).
While negative anomalies were weakening near the surface, the sub-surface
temperature anomalies (averaged across 180°-100°W) warmed due to the eastward
propagation of a downwelling equatorial oceanic
Kelvin wave (Fig. T17). Convection was suppressed near and
east of the Date Line and enhanced over the far western tropical Pacific Ocean
Low-level wind anomalies were easterly over the east-central Pacific,
and westerly over the far western Pacific. At upper-levels, winds
were anomalously westerly over the eastern Pacific (Figs. T20, T21). Overall, the ocean and atmosphere system
remained consistent with a weak La Niña.
models in the IRI/CPC plume predict La Niña will decay and return to
ENSO-neutral during the current March-May season (Figs. F1-F13).
The forecaster consensus similarly favors a transition to neutral, with a
continuation of ENSO-neutral conditions through the summer 2018. Thereafter,
there is considerable forecast uncertainty, in part due to the lower prediction
skill for forecasts made at this time of year. In summary, La Niña is expected to transition to
ENSO-neutral during April-May, with ENSO-neutral then likely (greater than 50%
chance) to continue through the Northern Hemisphere summer 2018 (click CPC/IRI consensus forecast for the chance of each outcome for
each 3-month period).
updates of oceanic and atmospheric conditions are available on the Climate
Prediction Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).