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 (CFSv2) 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 from the ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633‑652) are shown in Fig. F9.  Niño 3.4 predictions are summarized in Fig. F10, 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 anticipated to continue through the Northern Hemisphere winter (with greater than 95% chance through January - March 2024).

 

Discussion:

 

In August, sea surface temperatures (SSTs) were above average across the equatorial Pacific Ocean (Fig. T18), with strengthening in the central and east-central Pacific. All of the monthly Niño indices were at or in excess of +1.0C: Niño-4 was +1.0C, Niño-3.4 was +1.3C, Niño-3 was +2.0C, and Niño1+2 was +3.3C (Table T2). Area-averaged subsurface temperatures anomalies increased compared to July in association with anomalous warmth in the central and eastern equatorial Pacific Ocean (Fig. T17). Tropical atmospheric anomalies were also consistent with El Niño.  Over the east-central Pacific, low-level winds were anomalously westerly, while upper-level winds were anomalously easterly (Figs. T20 & T21). Convection was slightly enhanced around the International Date Line, stretching into the eastern Pacific, just north of the equator. Convection was mostly suppressed around Indonesia (Fig. T25). The equatorial Southern Oscillation Index (SOI) and the traditional station-based SOI were both significantly negative (Figs. T1 & T2). Collectively, the coupled ocean-atmosphere system reflected El Niño.

The most recent IRI plume indicates El Niño will persist through the Northern Hemisphere winter 2023-24 (Figs. F1-F12). Despite nearly the same ensemble mean amplitude as last month, the shorter forecast horizon means that the odds of at least a “strong” El Niño (>=1.5C for the November-January seasonal average in Niño-3.4) have increased to 71%.  However, a strong El Niño does not necessarily equate to strong impacts locally, with the odds of related climate anomalies often lower than the chances of El Niño itself (e.g., CPC’s seasonal outlooks). In summary, El Niño is anticipated to continue through the Northern Hemisphere winter (with greater than 95% chance through January - March 2024).

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