Why hasn't El Niño been declared yet? The answer might lie in the gradients of sea surface temperatures across the tropical Pacific Ocean.
It's not all about ENSO: other important climate patterns impact the United States during the Northern Hemisphere winter season, too.
Sea surface temperatures are up. So why haven't forecasters declared El Niño conditions?
One of ENSO’s most important influences is to the Indian Monsoon—the large-scale circulation pattern that brings the Indian subcontinent the vast majority of its yearly rainfall. And while La Niñas tend to increase monsoon rainfall, the monsoon’s relationship with El Niño can be a little more complicated.
The Signal and the Noise is often mentioned in reference to ENSO forecasting and not just in reference to Nate Silver’s bestselling book. In fact, understanding what is signal and what is noise is critical to interpreting predictions from models and climate science in general.
We’d like our forecasts—both weather and climate—to be simple and certain. Because of the fluid and chaotic nature of the ocean and atmosphere, however, forecasts are never about certainty: they’re about probability.
How does El Niño affect U.S. winter temperature and precipitation?
Chances that an El Niño will occur by summer are above 70%, hitting 80% by the fall. But subsurface temperature anomalies have tapered off some from earlier this spring, decreasing the odds the event will be as strong as the El Niño of 1997-98.
El Niño typically favors stronger hurricane activity in the central and eastern Pacific basins, and suppresses it in the Atlantic basin. Where does that leave the 2014 hurricane outlook?
If the climate conditions that indicate ENSO are best measured as seasonal averages, will scientists wait for conditions to persist three months before declaring El Niño underway?