Not only will the El Nino possibly turn out to be the strongest on record, but forecasters have determined it will not reach its peak until November or December this year, lasting into the first few months of 2016.
The effects on the climate from this year’s El Nino could be something to look forward to if you happen to live in Southern California, despite the mudslides and flooding that may occur. But the drought-plagued Pacific Northwest may not be so lucky because generally, El Nino usually brings drier weather to this region.
But California and the Pacific Northwest, going clear up into Western Canada is in dire need of a good steady rain and snowfall this winter. And while the southern tier of the United States can expect increased wet weather this winter because of El Nino, globally, many countries are going to be adversely affected.
The same El Nino that will bring heavy rains to part of the U.S. will give Australia, Indonesia and parts of India drier-than-normal conditions. Without a doubt, the current El Nino is unusual, and how scientists monitor this cyclical climate phenomenon is interesting.
Forecasting El Nino is a collaboration of assets from several countries
So what is El Nino? The ocean is a vast bowl of water that is constantly in motion. Many years ago, Peruvian and Ecuadorian fishermen noticed that every so often, in the winter usually before Christmas, the ocean currents would become warmer, bringing in a period of several months where fishing became poor. They began referring to this phenomenon as “El Nino,” or the Christ Child.
And that is what El Nino does. It warms the central to eastern tropical Pacific Ocean, sometimes reaching an area greater than the size of the United States. This event takes place on average every two to seven years, and is a complex mix of sea-surface temperatures and atmospheric conditions.
Normally, the trade winds blowing out of the East drive colder water from the depths of the Eastern Pacific Ocean to the surface. But occasionally, those winds weaken, and the ocean surface warms, causing the air above the surface to heat up as well. The warm air rises, moving north and south, changing the high-altitude air currents along which storms tend to travel.
The sea-surface temperatures are monitored regularly by meteorologists in Japan, Australia, and the United States. Particular attention is paid to a region in the Eastern Pacific known as Nino 3.4. This region’s water surface temperatures are critical to an event being called El Nino.
To be called an El Nino event, according to NOAA, sea-surface temperatures (SSTs) must remain at or above 0.5°C (about 1°F) for at least three months across the region labeled Nino 3.4. NOAA keeps detailed historical records for Nino 3.4 temperature readings.
Based on the SST readings, a “moderate” event has readings at or above 1.0°C, and a “strong” event would be 1.5°C or higher. Australian meteorologists use a 0.8 degrees C threshold rather than 0.5 degrees C only because a greater amount of SST warming is needed to reach Australia. Water temperatures below the ocean surface are also tracked, as well as air pressure above the surface. All this information is fed into computer modeling programs.
Why is this El Nino unusual?
For one thing, this El Nino started in March this year. This is much earlier than the usual June start. Some scientists think this is because warm waters from last year’s weak El Nino were left over in the ocean basin, giving this year’s El Nino a head start. At least that’s what Anthony Barnston, the chief forecaster at the International Research Institute for Climate and Society at Columbia University in Palisades, New York, thinks.
This year’s El Nino is also the second of a “double-header” event. An El Nino double-header happened between 1986 and 1988, but forecasters are saying this El Nino is going to be a record-breaker.
