Forecast Forum

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 skill.

 

ENSO Alert System Status: La Niña Advisory

 

Outlook:

 

La Niña is likely (~85-95%) through the Northern Hemisphere winter, with a transition to ENSO-neutral expected during the spring.

 

Discussion:  

 

La Niña continued during December, as indicated by the pattern of below-average sea surface temperatures (SSTs) across the central and eastern equatorial Pacific Ocean (Fig. T18).  The monthly Niño-3.4 index value was -0.8°C, and the Niño-3 and Niño-1+2 indices were below -1.0°C (Table T2).   Negative sub-surface temperature anomalies in the central and east-central equatorial Pacific weakened at the end of the month as anomalously warm waters in the western Pacific at depths greater than 100 m propagated eastward to approximately 140°W (Fig. T17).  The atmospheric conditions over the tropical Pacific Ocean also reflected La Niña, with suppressed convection near and east of the International Date Line and enhanced convection to the north of Indonesia (Fig. T25).  Also, the low-level trade winds continued to be stronger than average over the western and central Pacific (Fig. T20).  Overall, the ocean and atmosphere system remained consistent with La Niña.

 

Nearly all models in the IRI/CPC plume predict La Niña will persist through the Northern Hemisphere winter 2017-18 (Figs. F1-F13). Based on the latest observations and forecast guidance, forecasters believe this weak-to-moderate La Niña (3-month Niño-3.4 values between -0.5°C and -1.5°C) is currently peaking and will eventually weaken into the spring.  In summary, La Niña is likely (~85-95%) through the Northern Hemisphere winter, with a transition to ENSO-neutral expected during the spring.

 

Weekly updates of oceanic and atmospheric conditions are available on the Climate Prediction Center homepage (El Niño/La Niña Current Conditions and Expert Discussions).