National Weather Service United States Department of Commerce

Powerful Nor'easter To Wallop Parts Of The Northeast and New England

A powerful Nor'easter and winter storm is expected to wallop eastern parts of the Northeast and New England this weekend. Plenty of hazards are expected to impact the Northeastern U.S. from heavy snow, with significant accumulations expected, to high winds and coastal issues. The combination of the intense snow and strong winds will result in blizzard conditions, especially along coastal areas. Read More >

El Niño Southern Oscillation (ENSO)

Current Conditions

Tropical Pacific Sea Surface Temperatures:

Tropical Pacific Sea Surface Temperatures

Tropical Pacific Sea Surface Temperature Anomalies:

Tropical Pacific Sea Surface Temperature Anomalies

What is the El Niño Southern Oscillation (ENSO)?

 

Most of the information here is courtesy of climate.gov.

The El Niño Southern Oscillation is a recurring climate pattern across the tropical Pacific. The two phases, El Niño (the warm phase) and La Niña (the cool phase), represent the opposite extremes in the ENSO cycle, with ENSO-neutral conditions the third phase where conditions are near average. This oscillation is characterized by differences in ocean temperatures, winds, surface pressure, and rainfall across the parts of the tropical Pacific, which can influence weather across the globe.

  • El Niño: A warming of the ocean surface, or above-average sea surface temperatures (SST), in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall tends to become reduced while rainfall increases over the tropical Pacific Ocean. The low-level surface winds, which normally blow from east to west along the equator (“easterly winds”), instead weaken or, in some cases, start blowing the other direction (from west to east or “westerly winds”).
  • La Niña: A cooling of the ocean surface, or below-average sea surface temperatures (SST), in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall tends to increase while rainfall decreases over the central tropical Pacific Ocean. The normal easterly winds along the equator become even stronger.
  • Neutral: Neither El Niño or La Niña. Often tropical Pacific SSTs are generally close to average. However, there are some instances when the ocean can look like it is in an El Niño or La Niña state, but the atmosphere is not playing along (or vice versa).

ENSO Sea Surface Temperature Anomalies

Maps of sea surface temperature anomalies in the Pacific Ocean during a strong La Niña (top, December 1988) and El Niño (bottom, December 1997). Maps by NOAA Climate.gov

We focus on ENSO due to its significant impact on the global atmospheric circulation, which influences temperature and precipitation patterns across the globe. It is also one of the most skillfully predicted climate modes, giving us advanced notice of weather and climate patterns.

ENSO Winter Patterns for the United States

Wintertime El Niño (top) and La Niña (bottom) weather patterns across the United States.

Latest Forecasts from the Climate Prediction Center and the International Research Institute

 

Latest Probabilistic Forecast

 

 

Latest Model Guidance

El Niño Temperature and Precipitation Anomalies

 

Below are winter (December-January) temperatures and precipitation anomalies for El Niño episodes since 1950. These composites are not meant to be a forecast of expected conditions. Rather, they use historical data to highlight where ENSO phases can potentially impact temperature and precipitation. Other climate modes, as well as atmospheric variability, makes each ENSO event unique and make impacts different.

 

Weak El Niño Temperature Anomalies
Weak El Niño Precipitation Anomalies

 

 

Moderate/Strong El Niño Temperature Anomalies
Moderate/Strong El Niño Precipitation Anomalies

La Niña Temperature and Precipitation Anomalies

 

Below are winter (December-January) temperatures and precipitation anomalies for La Niña episodes since 1950. These composites are not meant to be a forecast of expected conditions. Rather, they use historical data to highlight where ENSO phases can potentially impact temperature and precipitation. Other climate modes, as well as atmospheric variability, makes each ENSO event unique and make impacts different.

 

Weak La Niña Temperature Anomalies
Weak La Niña Precipitation Anomalies

 

 

Moderate/Strong La Niña Temperature Anomalies
Moderate/Strong La Niña Precipitation Anomalies

Long Range Outlooks from the Climate Prediction Center

 

One Month Temperature Outlook
One Month Precipitation Outlook

 

 

Three Month Temperature Outlook
Three Month Precipitation Outlook