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: Not Active

 

Outlook:

 

ENSO-neutral is favored through the Northern Hemisphere summer (78% chance for the June-August season) and fall (50% chance for the September-November season).

 

Discussion:

 

ENSO-neutral conditions continued during May, with near-average sea surface temperatures observed across most of the equatorial Pacific Ocean (Fig. T18).  In the last month, the Niño indices were between -0.1ºC and -0.4ºC, except for the Niño-1+2 index, which was -0.7ºC (Table T2).  Subsurface temperature anomalies remained positive but decreased slightly due to the weakening of above-average subsurface temperatures around the thermocline in the central Pacific Ocean (Fig. T17).  Low-level easterly (Fig. T20) and upper-level westerly (Fig. T21) wind anomalies extended across most of the equatorial Pacific Ocean.  At the Date Line, tropical convection was mostly near average, and enhanced rainfall was evident over the western Pacific Ocean (Fig. T25).  Overall, the ocean and atmosphere system reflected ENSO-neutral conditions.

A majority of the models in the IRI/CPC plume predict ENSO-neutral to continue through the fall 2021 (Figs. F1-F12).  The forecaster consensus generally agrees with this model outlook, although lower probabilities are assigned to El Niño during this period (remaining less than 10%).  By the late fall and winter, La Niña chances increase to near 50%, reflecting the historical tendency for a second winter of La Niña following the first, and also the predictions from the North American Multi-Model Ensemble.  However, these cooler conditions are predicted to exist for a short duration (3 overlapping seasons) and these predictions are still over 6 months into the future.  In summary, ENSO-neutral is favored through the Northern Hemisphere summer (78% chance for the June-August season) and fall (50% chance for the September-November season).

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