Current Status July 17, 2024
La Niña Watch
Forecasters have issued a La Niña Watch, indicating that the cool phase of the El Niño-Southern Oscillation ("ENSO") climate pattern is likely to develop in coming months, with a 79% chance it will be in place for the Northern Hemisphere winter. Whether it will arrive in time to exert a strong influence on the Atlantic hurricane season is still uncertain. Forecasters currently place the odds at 70 percent chance that La Niña will have settled in by the August-October season.
More ENSO
- Latest ENSO blog
- ENSO in a nutshell
- ENSO FAQs
- Popular El Niño and La Niña images
What Is ENSO
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 shifts back and forth irregularly every two to seven years, bringing predictable shifts in ocean surface temperature and disrupting the wind and rainfall patterns across the tropics. These changes have a cascade of global side effects.
More About el Niño
- What is El Niño in a nutshell?
- Understanding El Niño (video)
- FAQs
- NOAA's ENSO alert system
- ENSO essentials
- Educational Resources on ENSO
Typical U.S. impacts
El Niño and La Niña have very little impact on summer climate in the contiguous United States. Their strongest influence occurs in winter. But they do influence the seasonal hurricane activity in the two basins that impact the United States. La Niña favors below-average hurricane activity in the East Pacific and above-average activity in the Atlantic. The strong chance of La Niña later this summer is one of the factors leading NOAA forecasters to predict a much more active Atlantic Hurricane season than usual in 2024.
More U.S. impacts
- Winter temperature and precipitation
- Hurricane season impacts
- ENSO and tornadoes
More About el Niño
Global Resources
- ENSO @ the Australian Bureau of Meteorology
- ENSO @ the World Meteorological Organization
- ENSO @ the International Research Institute for Climate & Society
- ENSO @ Instituto del Mar del Perú (IMARPE) (Spanish)
- ENSO @ the Centro Internacional para la Investigación del Fenómeno de El Niño (CIIFEN) (Spanish)
ENSO Blog
ENSO and the southwest United States "megadrought”
ENSO August 28, 2024
La Niña conditions are likely for later this year. What could that mean for drought in the Southwest?
Read More
Global Impacts
El Niño and La Niña have weaker impacts during Northern Hemisphere summer than they do in winter. Summer impacts include warm conditions in northeastern Australia and cooler than average conditions across India and Southeast Asia.
More About el Niño
- ENSO's cascade of global impacts
- The Walker Circulation
- More maps of global impacts of La Niña and El Niño
ENSO Videos
Featured Resources & Articles
- El Niño and La Niña: Frequently asked questions
Understanding the ENSO Alert System
Understanding the ENSO Alert System
On the second Thursday of each month, scientists with NOAA’s Climate Prediction Center in collaboration with forecasters at the International Research Institute for Climate and Society (IRI) release an official update on the status of the El Niño-Southern Oscillation (ENSO). Here is a description of the categories and criteria they use.
- Watch:Issued when conditions are favorable for the development of El Niño or La Niña conditions within the next six months.
- Advisory:Issued when El Niño or La Niña conditions are observed and expected to continue.
- Final advisory: Issued after El Niño or La Niña conditions have ended.
- Not Active:ENSO Alert System is not active. Neither El Niño nor La Niña are observed or expected in coming 6 months.
Summary of NOAA decision process in determining El Niño conditions. NOAA Climate.gov drawing by Glen Becker and Fiona Martin.
Flowchart showing decision process for determining La Niña conditions. Figure by Fiona Martin, adapted by Climate.gov.
El Niño criteria
- Average sea surface temperatures in theNiño-3.4 regionof the equatorial Pacific Ocean were at least 0.5°C (0.9°F) warmer than average (5°N-5°S, 120°W-170°W) in the preceding month,and
- the anomaly has persisted or is expected to persist for 5 consecutive, overlapping 3-month periods (e.g., DJF, JFM, FMA, etc),and
- the atmosphere over the tropical Pacific exhibits one or more of the changes commonly associated with El Niño:
- weaker than usual easterly trade winds,
- reduced cloudiness and rainfall over Indonesia and a corresponding increase in the average surface pressure, or
- increased cloudiness and rainfall in central or eastern part of the basin and a corresponding drop in the average surface pressure.
La Niña criteria
- Average sea surface temperatures in the Niño-3.4 region of the equatorial Pacific Ocean (5°N-5°S, 120°W-170°W) were at least 0.5°C (0.9°F) cooler than average in the preceding month, and
- an average anomaly of at least -0.5°C has persisted or is expected to persist for 5 consecutive, overlapping 3-month periods (e.g., DJF, JFM, FMA, etc), and
- the atmosphere over the tropical Pacific exhibits changes commonly associated with La Niña, including one or more of the following:
- stronger than usual easterly trade winds,
- an increase in cloudiness and rainfall over Indonesia and a corresponding drop in average surface pressure,
- a decrease in cloudiness and rainfall in the eastern tropical Pacific, and an increase in the average surface pressure.
