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 ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633‑652) are shown in Fig. F11.  Niño 3.4 predictions are summarized in Fig. F12, 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: El Niño Advisory

 

Outlook:

 

El Niño is predicted to persist through the Northern Hemisphere summer 2019 (66% chance), with lower odds of continuing through the fall and winter (50-55% chance).

 

Discussion:

 

During May, El Niño was reflected in the continued presence of above-average sea surface temperatures (SSTs) across most of the equatorial Pacific Ocean (Fig. T18).  The monthly ENSO indices were +0.8C in Niño-4, +0.7C in Niño-3.4, +0.6C in Niño-3, and +0.2C in Niño-1+2 regions (Table T2). Upper-ocean subsurface temperatures (averaged across 180-100W) were nearly average at the start of May, but positive anomalies increased toward the end of the month in association with a downwelling Kelvin wave.  Thus, anomalies remained positive at depth in the central equatorial Pacific Ocean, with negative anomalies evident in the eastern Pacific (Fig. T17).  Suppressed tropical convection continued over Indonesia, while weak, enhanced convection persisted near the Date Line (Fig. T25).  Low-level wind anomalies were westerly over the western tropical Pacific Ocean (Fig. T20), and upper-level wind anomalies were easterly over the western and east-central Pacific (Fig. T21).  Overall, oceanic and atmospheric conditions were consistent with El Niño. 

 

The combined averages in the IRI/CPC plume predict El Niño to continue into Northern Hemisphere winter 2019-20, but individual models span ENSO-neutral to El Niño outcomes (generally +0.0C to +1.0C; Figs. F1-F12).  The forecast consensus reflects this uncertainty, with slightly lower chances for El Niño compared to the previous month.  Ongoing subseasonal variability within the tropical Pacific contributes to an overall murky picture, but the current downwelling oceanic Kelvin wave should fuel the persistence of El Niño at least in the short-term.  In summary, El Niño is predicted to persist through the Northern Hemisphere summer 2019 (66% chance), with lower odds of continuing through the fall and winter (50-55% chance).

 

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