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: La Niña Advisory

 

Outlook:

 

La Niña is favored to continue through the Northern Hemisphere winter 2021-22 (~95% chance) and transition to ENSO-neutral during the spring 2022 (~60% chance during April-June).

 

Discussion:

 

In November, the continuation of La Niña was reflected in the below-average sea surface temperatures (SSTs) extending across the equatorial Pacific Ocean (Fig. T18).  For the month, all of the Niño indices were between -0.6ºC and -1.0ºC, with the largest departure occurring in the easternmost Niño-1+2 region (Table T2).  Below-average subsurface temperatures weakened slightly compared to the previous month, but a large pool of negative temperature anomalies still extended across the central and eastern Pacific, down to ~200m depth (Fig. T17).  Low-level easterly and upper-level westerly wind anomalies persisted over most of the equatorial Pacific (Fig. T20 & T21).  Enhanced convection and rainfall were observed over Indonesia and convection was suppressed over the central and western equatorial Pacific (Fig. T25). The Southern Oscillation Index and Equatorial Southern Oscillation Index were more positive than the previous month (Fig. T1 & T2). Overall, the coupled ocean-atmosphere system was consistent with La Niña. 

The IRI/CPC plume average of forecasts for the Niño-3.4 SST index indicates La Niña will continue through the February-April 2022 season (Figs. F1-F12).  The forecaster consensus anticipates a transition to ENSO-neutral sometime during the Northern Hemisphere spring, with chances for La Niña declining below 50% after March-May 2022.  The chance of a moderate-strength La Niña declined slightly from last month’s update, but there is still a 59% chance of the Niño-3.4 index reaching a value less than -1.0ºC for the November 2021 – January 2022 season.  In summary, La Niña is favored to continue through the Northern Hemisphere winter 2021-22 (~95% chance) and transition to ENSO-neutral during the spring 2022 (~60% chance during April-June).

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