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Date: 8/21/2018

Title: El Nino or No El Nino?

By Don Day, Jr., Meteorologist

As we look ahead into the fall and winter season it is critical to begin to understand the mood of the Pacific Ocean regarding what the fall and winter season will bring the U.S. Pockets of warm and cool water and where they reside in the tropical and subtropical Pacific can have a big impact on long term weather trends, especially during the winter and spring seasons ahead.

During the winter/spring of 2017/2018 a moderate La Nina (cool Pacific) dominated the weather pattern. Since then, sea surface temperatures have warmed some leading some to believe (including many computer models) that we are headed into an El Nino this winter and coming spring. If an El Nino develops it could mean a milder winter and needed rains for the far western states (including California) and warmer than normal winter temperatures in many areas of the U.S. 

Several computer models, including the American CFS model predicts a classic El Nino pattern in the Pacific from December to February. Notice in the graphic below the stripe of orange from west of South America to east of Australia. The orange areas show warmer waters and a classic El Nino.

The European modeling is suggesting the same thing (although not as strong) as you can see below. 

If we were to take the computer models by face value, we would be predicting a fairly strong El Nino this winter and following spring. However, we have seen failed predictions of an El Nino before. Most recently, we had an El Nino predicted in 2017 that ended up a La Nina! There have been other failed El Nino predictions before.

Despite the agreement in the modeling there are hints that the predicted El Nino of 2018/2019 may not come to fruition. Sea surface temperatures have been stubborn to warm up in key areas over the past few weeks.

In a nutshell, don’t buy any forecasts of an El Nino this winter yet, we have several more weeks where changes in predictions may occur.