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
ENSO Alert System Status: La Niña Advisory
La Niña is likely to continue through the Northern Hemisphere winter
2021-22 (~90% chance) and into spring 2022 (~50% chance during March-May).
Niña strengthened in the last month, with below-average sea surface
temperatures (SSTs) evident across most of the equatorial Pacific (Fig. T18). For the past month, all of the Niño index
values were between -0.5ºC and -0.8ºC, with the exception of the Niño-1+2
region (Table T2).
Below-average subsurface temperatures (averaged from 180-100ºW) were
roughly the same amplitude at this time last month, and reflected the
prevalence of below-average temperatures in the eastern Pacific Ocean (Fig. T17). Low-level easterly and upper-level westerly
wind anomalies were again observed over parts of the equatorial Pacific, although
weaker than last month (Figs. T20 & T21). Tropical convection was suppressed near and
west of the Date Line and was slightly enhanced over Indonesia (Fig. T25). The Southern Oscillation Index and Equatorial
Southern Oscillation Index remained positive (Figs. T1 & T2). Overall, the coupled
ocean-atmosphere system was consistent with La Niña.
IRI/CPC plume average of forecasts for the Niño-3.4 SST index favors La Niña to
continue through January-March 2022 season (Figs. F1-F12). The
forecaster consensus anticipates La Niña to persist longer, potentially
returning to ENSO-neutral during April-June 2022. The Niño-3.4 index has a 66% chance of
reaching a value less than -1.0ºC during November 2021 – January 2022, but only
a 14% chance of being below -1.5ºC. Thus,
at its peak, a moderate-strength La Niña is favored. In summary, La Niña is likely to continue through the Northern
Hemisphere winter 2021-22 (~90% chance) and into spring 2022 (~50% chance
updates of oceanic and atmospheric conditions are available on the Climate
Prediction Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).