Temperatures in Pacific have risen.
The National Weather Service's Climate Prediction Center issued an El Niño watch, today.
That means there is a 50 percent chance that El Niño — warmer than normal temperatures in the Pacific Ocean near the equator — will develop by next winter. As The Baltimore Sun reports, if this happens it will be the first time El Niño rears its head since 2009.
The phenomenon is known to have broad implications for weather, including a less active hurricane season and a colder winter for the southern United States. In the Mid-Atlantic it's also caused very snowy winters.
"Several preseason hurricane forecasts, including those by Colorado State University and theNational Oceanic and Atmospheric Administration, estimated there would be fewer storms this year than last, based on predictions that an El Nino would form.
"El Niño enhances Atlantic Ocean wind shear, which is a change in speed or direction of winds at different levels in the atmosphere. The winds tear at the structure of growing tropical systems, preventing them from organizing or strengthening."
Earlier this month, Australia's Bureau of Meteorology said all of its climate models pointed to a return of El Niño. La Niña, reports ABC Rural, is thought to have brought significant flooding to Australia. Bloomberg reports that two seasons of La Niña have "drenched parts of Asia."