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: Final El Nino Advisory/ La Nina Watch

 

Outlook: ENSO-neutral conditions are present. La Nina is favored to develop during July-September (65% chance) and persist into the Northern Hemisphere winter 2024-25 (85% chance during November-January).

 

Discussion:

 

ENSO-neutral conditions returned during the past month. Near-to-below average sea surface temperatures (SSTs) expanded across the eastern equatorial Pacific Ocean (Fig. T18). The most recent monthly Nino-3.4 index was +0.3C, while SST anomalies remained cooler in the far eastern Nino-1+2 region (-0.7C) and warmer in the western Nino-4 region (+0.7C; Table T2). Below-average subsurface temperatures were mostly unchanged during the past month, with negative anomalies persisting in the eastern half of the Pacific (Fig. T17). Low-level wind anomalies were easterly over the east-central equatorial Pacific, and upper-level winds were near average (Figs. T20 & T21). Convection was mostly average around Indonesia, while below-average rainfall strengthened near the Date Line (Fig. T25). Collectively, the coupled ocean-atmosphere system reflected ENSO-neutral conditions.

The most recent IRI plume indicates La Nina may develop during July-September 2024 and then persist through the Northern Hemisphere winter (Figs. F1-F12). The forecast team is also favoring the development of La Nina during July-September because the rate of cooling has slowed since last month. The team still favors La Nina to emerge sometime during the summer months, given the persistent below-average subsurface ocean temperatures and changes in the tropical atmospheric circulation.  In summary, ENSO-neutral conditions are present. La Nina is favored to develop during July-September (65% chance) and persist into the Northern Hemisphere winter 2024-25 (85% chance during November-January).

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