El Nino Peaking
The much discussed El Nino weather pattern in the subtropical Pacific will be reaching its peak over the course of the next thirty days. Reaching its peak means the moment when the water temperatures reach their warmest levels and begin to decrease. However, due the lag in time between the subtropical waters cooling and the impacts of the warmer waters this summer and fall, the impacts of El Nino will persist into early 2016 even though water temperatures will soon reach their warmest levels.
While the El Nino of 2015/2016 will be a very strong one, it will be falling short of the Super El Nino of 1997/98. The chart below illustrates the differences in sea surface temperatures between the El Nino of 1997/98 and this season’s El Nino. The sea surface temperature anomalies in 1997/98 were as high as 8 to 9C, while this year’s El Nino is as high as 6 to 7C.
It should also be pointed out that no two El Nino behave the same as there are other climatological influences that play critical roles in regards to how winters and springs will unfold.
All long range weather modeling suggests that El Nino will be peaking soon and the water temperatures in the subtropical Pacific will begin to cool rather rapidly. In fact, by May or early June, water temperatures in the subtropical Pacific may actually drop to below normal and we may have a developing La Nina (colder than normal water temperatures). The big swings from an El Nino to a La Nina are quite commonplace. Therefore by late spring or summer 2016, the impacts of El Nino will fade fast and the impacts of La Nina could be a factor by next summer and fall.
Over the past several weeks we have witnessed some classic El Nino influenced weather patterns across the United States. The heavy rains in the southern states since mid-October have been partly due to El Nino.
The graphic below shows total precipitation across the lower 48 states over the past thirty days. The heavy precipitation in the Carolinas, Texas and the Gulf Coast states are easily seen along with some good rains in the Pacific Northwest.
Over the course of the next few weeks, California can expect some good chances for rain as well as some high Sierra snows.