What happens after La Niña ends? I get this question a lot, and it is always a tough one to answer. Why? Well…1) La Niña is still firmly in control and 2) The PDO (Pacific Decadal Oscillation) is still quite cold/negative. So, to provide a good speculation on what will happen, I would first like to see one of these things change. However, that hasn’t happened… For now, let’s just say that La Niña ends later this winter and the PDO warms up a bit. Is La Niña expected to do that? Yes… The graphic below shows strong probabilities of that happening late this winter.
The overall forecast also calls for neutral conditions by spring, with a possibility of an El Niño by later next year. On the other hand, the PDO has really shown no signs of warming up. Here is the PDO trend for this year.
As you can see, it is still quite cold/negative, and has not shown any signs of changing. This also begs the question: When was the last time we had a strongly negative PDO and a triple dip La Niña? The answer? From late 2010 through early 2013. What did the transition look like as those things changed? Well, here is how the PDO evolved…
You can see it was strongly negative in October of 2013, came back to neutral by spring of 2014, and then went into a warm/positive model thereafter. That transition was huge, because it allowed an El Niño to develop, which allowed for some pretty significant precipitation for drought-stricken areas.
Here are the precipitation anomalies that occurred as we finished 2013.
Here are the January - May 2014 precipitation anomalies…
You can still see the impact of the La Niña hangover, and the linger cold/negative PDO…just look at all that drier than average in California, Desert Southwest, and in the Plains. Classic negative PDO precipitation signature… However, this really changed during the back half of 2014, as the PDO warmed and we were more removed from the La Niña.
Many areas that were drier than average for months, suddenly became wetter than average. Some areas still struggled a bit…note Eastern Texas. However, that quickly changed as we entered 2015 and dealt with a pretty stout El Niño. Here are the precipitation anomalies from all of 2015.
So, are we going to see a transition similar to what happened in late 2013 and 2014? To be honest, I really don’t know… However, this is the last sample we had of this type of transition. Could this be an analog situation to where we are right now? Despite my uncertainty, I am giving it a strong look. However, I would certainly want to see the PDO warm a bit, before I start to get excited. Once the PDO starts to warm, we can possibly start making some plans to capitalize on this change. Fingers crossed…