El Niño & La Niña (El Niño-Southern Oscillation)
A strong El Niño currently underway is expected to gradually weaken through spring 2016, and to transition to ENSO-neutral during late spring or early summer. This event has already produced significant global impacts, and it is likely to affect U.S. temperature and precipitation patterns during the upcoming months. The next official update will be on February 11.
El Niño and La Niña are the warm and cool phases of a recurring climate pattern across the tropical Pacific—the El Niño-Southern Oscillation, or “ENSO” for short.
The pattern can shift back and forth irregularly every two to seven years, and each phase triggers predictable disruptions of temperature, precipitation, and winds.
These changes disrupt the large-scale air movements in the tropics, triggering a cascade of global side effects.
El Niño makes certain seasonal patterns more likely, but not guaranteed. El Niño winters tend to be wetter and slightly cooler than average across southern states; warmer than average in Alaska, the Pacific Northwest, and as far east as the Great Lakes; and dry in the Ohio Valley. The location of the greatest winter tornado activity tends to be in the Southeast.
El Niño has its strongest impact on global climate during the Northern Hemisphere winter & early spring. The most reliable global impacts are dryness over Indonesia and northern South America, below-average rains during the Indian Monsoon, and excess rainfall in southeastern South America, eastern Africa near the equator, and across the southern U.S.
Hurricane activity is often suppressed in the Atlantic and amplified in the eastern North Pacific. The risk of coral bleaching increases, and populations of marine plants in the eastern tropical Pacific (and the animals that depend on them) sometimes crash.
How likely is a La Niña the year after an El Niño, and in particular after a strong one like this year's? IRI's Tony Barnston analyzes the history of ENSO behavior since 1950 for a possible answer.
Featured Resources & Articles
ENSO across NOAA
Societal & ecosystem impacts
Regional & Local Impacts
ENSO @ the Ocean Institute of Peru (Spanish)
ENSO @ the Centro Internacional para la Investigación del Fenómeno de El Niño (CIIFEN) (western South America, Spanish)
Events & Announcements
NOAA National Weather Service Daily Briefing
Briefing page with forecasts, discussions, maps, assessments, and severe weather outlooks for today’s developing weather patterns across the United States.
NOAA Monthly Climate Briefing for Media
Thursday, February 18, at 11 am EST
Teleconference for public media on past month’s weather & climate conditions for the U.S. & globe, an update on El Niño, and NOAA’s 3-month climate outlook.
California Winter Status Update
January 26, 4 - 6 pm EST