How does El Niño/La Niña affect tropical cyclone development in the Atlantic basin?
Even though El Niño and La Niña take place in the waters of the tropical Pacific Ocean, their impacts can be felt far and wide as they alter the Earth’s normal atmospheric circulation patterns. A 1998 study by Florida State University and the National Oceanic and Atmospheric Administration found that during an El Niño event, when water in the tropical Pacific Ocean is unusually warm, fewer hurricanes tend to make landfall in the USA. In the Atlantic, during moderate and strong El Niño events, westerly high altitude winds are stronger than normal, disrupting the formation and longevity of hurricanes. Conversely, there are more hurricanes during a La Niña event, when the Pacific Ocean is cooler and the high-altitude winds are diminished. The study also found that in a neutral (i.e., no El Niño or La Niña) year that there was a 48 percent chance of at least two hurricanes making landfall on the United States. With an El Niño in place, that number dropped almost in half to 28 percent, whil