El Niño: One of Nature’s Biggest Weather Makers

 

Possible Impacts Where You Live

Some of the patterns that are often observed during strong El Niños in the U.S. include:

  • Above-average temperatures in portions of Alaska, the Pacific Northwest, Intermountain West, Northern Plains and Upper Midwest
  • Below-average rainfall in the northern Rockies, and the Ohio and Tennessee Valleys.
  • Above-average rainfall in southern California, Arizona, New Mexico, Texas and Florida.

The main influence of El Niño in the U.S. summer tends to be on hurricanes:

  • More tropical cyclones in the Pacific
  • Fewer tropical cyclones in the Atlantic.

El Niño has arrived, according to forecasters with NOAA’s Climate Prediction Center, and it’s making big news. But why? It simply comes down to the extensive impact El Niño has on the world’s weather patterns.

 

When an El Niño develops, it can start a chain reaction in the atmosphere influencing the weather in places much farther away from the tropical equatorial Pacific Ocean, including the United States. This means certain changes to the typical climate, or long-term average for temperature or precipitation, for folks in some parts of the U.S. Climate is like the tides. Just like the tides roll in and out, our climate warms during the summer and cools during the winter. El Niño’s would be like changing the level of those tides in some places. Perhaps they come in a little higher or earlier now, getting you wet before you have a chance to move your blanket back.

The map above highlights areas of the U.S. that experience temperature or precipitation conditions that may be different from normal when an El Niño is present. Impacts from El Niño are most noticeable during the late fall through early spring months. During late spring and summer, climate patterns may not be affected at all.

Not every El Niño event leads to the same climate conditions, however, and the strength of the El Niño event can have an impact on just how warm, cool, dry, or wet the affected areas become. As of summer 2015, the current El Niño has strengthened over the past few months, with a strong event currently favored during the late fall and early winter, according to the latest report from the Climate Prediction Center.

In instances when a strong El Niño occurs, there can be large impacts to communities and the U.S. economy. Strong El Niños are often associated with heavy winter rains across California, which could bring much needed moisture to a region devastated by drought. Even if above normal precipitation falls across California, one season of above-normal rain and snow is very unlikely to erase four years of drought.

Meanwhile, heavy rains in the southern half of the U.S. could lead to flooding causing widespread damage to towns and communities, lives and livelihoods. In addition, El Niño could elevate the risk for severe weather across the Southeast during winter. On the other hand, above-average late fall to winter temperatures across the northern tier of the U.S. might mean a milder winter and lower energy costs. It’s important to understand that a strong El Niño only favors these impacts, but doesn’t guarantee they will happen.

Visit NOAA’s U.S. Climate Resilience toolkit for safety tips on floods and drought from the National Weather Service.

For more information on El Niño, visit http://www.climate.gov/.