Monday, August 21, 2023

ENSO Forecast: It Looks Like This Year's El Niño Is Going To Be Very Strong

We'll be back tomorrow with some of the weather effects to look for but right now the ENSO Quick Look from IRI/Columbia University, August 18:

A monthly summary of the status of El Niño, La Niña, and the Southern Oscillation, or ENSO, based on the NINO3.4 index (120-170W, 5S-5N)

As of mid-Aug 2023, the previously moderate El Niño conditions in the central-eastern equatorial Pacific have strengthened further. Key oceanic and atmospheric variables are consistent with the El Niño, though the atmosphere is not yet fully coupled to the warm sea surface temperature anomalies in the central-eastern equatorial Pacific Ocean. A CPC El Niño advisory remains in place for August 2023. Almost all of the models in the IRI ENSO prediction plume forecast an El Niño event during boreal autumn continuing into winter and early spring of 2024, while weakening during the end of the forecast and ENSO-neutral become the most likely category (Apr-Jun 2024 with 59% chance).

Figures 1 and 3 (the official CPC ENSO probability forecast and the objective model-based IRI ENSO probability forecast, respectively) are often quite similar. However, occasionally they may differ noticeably. There can be several reasons for differences. One possible reason is that the human forecasters, using their experience and judgment, may disagree to some degree with the models, which may have known biases. Another reason is related to the fact that the models are not run at the same time that the forecasters make their assessment, so that the starting ENSO conditions may be slightly different between the two times. 

The charts on this Quick Look page are updated at two different times of the month, so that between the second and the third Thursday of the month, the official forecast (Fig. 1) has just been updated, while the model-based forecasts (Figs. 3 and 4) are still from the third Thursday of the previous month. On the other hand, from the third Thursday of the month until the second Thursday of the next month, the model-based forecasts are more recently updated, while the official forecasts remain from the second Thursday of the current month.
Click on the for more information on each figure.....


If the average of the dynamic models (thick red line) is anywhere close to being correct this is gonna be a strong 'un: