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 conditions are present and are expected to gradually strengthen into the
Northern Hemisphere winter 2023-24.
Discussion:
In May, weak El Niño conditions emerged as above-average
sea surface temperatures (SSTs) strengthened across the equatorial Pacific
Ocean (Fig. T18). Three of the Niño indices were more
than +0.5C: Niño-3.4 was +0.5C, Niño-3 was +0.9C, and Niño1+2 was +2.0C (Table T2).
Area-averaged subsurface temperatures anomalies remained positive, reflecting the
continuation of widespread anomalous warmth below the surface of the equatorial
Pacific Ocean (Fig. T17). For the May average, low-level
wind anomalies were westerly over the western equatorial Pacific Ocean (Fig. T20),
while upper-level wind anomalies were westerly over the eastern Pacific Ocean (Fig. T21).
Convection was enhanced along the equator and was suppressed over Indonesia (Fig. T25).
Both the equatorial SOI and traditional SOI were significantly negative. Collectively,
the coupled ocean-atmosphere system reflected the emergence of El Niño
conditions.
The
most recent IRI plume indicates the continuation of El Niño through the
Northern Hemisphere winter 2023-24 (Figs. F1-F12). Confidence in the occurrence
of El Niño increases into the fall, reflecting the expectation that seasonally
averaged Niño-3.4 index values will continue to increase. Another downwelling Kelvin wave is emerging
in the western Pacific Ocean, and westerly wind anomalies are forecasted to recur
over the western Pacific. At its peak, the chance of a strong El Niño is nearly
the same as it was last month (56% chance of November-January Niño-3.4 >=
1.5C), with an 84% chance of exceeding moderate strength (Niño-3.4 >= 1.0C). In summary, El Niño conditions are present
and are expected to gradually strengthen into the Northern Hemisphere winter
2023-24.
Weekly
updates of oceanic and atmospheric conditions are available on the Climate
Prediction Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).