El Niño & La Niña (El Niño-Southern Oscillation)

LA NIÑA WATCH (Oct. 12, 2017)

The atmosphere over the tropical Pacific was La Niña-like in September, but the required cooling of the ocean surface was interrupted in the second half of the month. However, the deeper waters in the east cooled further, and forecasters say the odds of at least a weak La Niña by late fall or winter are 55-65%. The next update will be on November 9.

More ENSO status information
Latest official ENSO update
Latest ENSO blog update
ENSO Monitoring at the Climate Prediction Center

 

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.

More about El Niño
What is El Niño in a nutshell?
Understanding El Niño (video)
FAQs
ENSO alert system criteria
ENSO essentials
Educational Resources on ENSO

La Niña, winter impacts

Cooler and wetter in the Northwest, warmer and drier across the South

La Niña is anchored in the tropical Pacific, but through the jet streams, it affects seasonal climate "downstream" in the United States. This map shows typical impacts of La Niña on U.S. winter weather based on past La Niñas, but the exact location and strength of impacts vary from event to event, and some might not occur at all. 

Typical U.S La Niña impacts
Winter temperature and precipitation
Hurricane season impacts
Current outlooks
6-10 day outlook
8-14 day outlook
1-month outlook
3-month outlook

La Niña winters

El Niño and La Niña have their strongest impact on global climate during the Northern Hemisphere winter.  The map at left shows typical December-February rainfall and temperature patterns during La Niña winters, but we may not see all impacts during every event. 

More information
ENSO's cascade of global impacts
The Walker Circulation
More maps of global impacts of La Niña and El Niño

October 2017 ENSO update: Still watching for La Niña

October 12, 2017

ENSO forecasters are maintaining the La Niña Watch, but not declaring La Niña, as we wait for the tropical Pacific to settle down.

Read more

 

(image at left) Weekly ocean surface temperatures from August–early October 2017 compared to the 1981-2010 average.