La Niña is officially coming – so how will it affect weather patterns?

Apr 18, 2016

This article is published in collaboration with Business Insider.

Dark clouds pass over downtown Miami, Florida August 15, 2010. An area of low pressure over southwest Georgia could move southward into Gulf of Mexico waters by early Monday and has a medium chance of becoming a tropical cyclone in the next 48 hours, the National Hurricane Center said on Sunday. The low pressure area was the remnant of Tropical Depression Five which dissipated on Wednesday in the Gulf. The U.S. Gulf of Mexico is home to about 30 percent of U.S. oil production, 11 percent of natural gas production, and more than 43 percent of U.S. refinery capacity.

The La Niña effect is associated with increased intensity and frequency of meteorological hazards such as hurricanes. Image: REUTERS/Carlos Barria

Lydia Ramsey

Editorial Intern, Business Insider Science

We're officially on a La Niña watch.

The National Oceanic and Atmospheric Administration (NOAA) said Thursday that it has initiated its La Niña watch after new predictions suggest it could be here as early as this fall.

If it does materialize, the La Niña weather pattern would be coming on the heels of a particularly record-breaking El Niño, which NOAA forecasts will end this summer.

While El Niños are marked by abnormally warm sea-surface temperatures, La Niñas are marked by abnormally cooler sea-surface temperatures. Those cooler sea-surface temperatures also tend to reduce something called wind shear, a phenomenon that occurs when winds change their speed and direction over short distances.

When winds can change their speed and direction quickly and easily, it makes hurricanes more likely because the area near the center of the storm can't cool down.

El Niños aren't always accompanied by La Niñas, NOAA points out. But if one does materialize this year, it will be the first one we've seen since the last one ended in 2012.

Here's a Gif of the changing sea-temperature anomalies happening now in the Pacific Ocean, which suggest a trend toward a La Niña:

Changing sea temperature anomalies in the Pacific Ocean

Image: GIPHY

If a La Niña does form, it won't just increase the risks of a more intense Atlantic hurricane season. It could also lead to warmer and drier winters in the southern part of the US, while the Pacific Northwest, southern part of Alaska, and Midwest could feel the chill of cooler-than-average temperatures.

That would be a change of pace compared with what El Niño did to the US this past winter, when the East Coast had seriously warm December temperatures while the south experienced flooding, and New Mexico, Texas, and parts of Oklahoma spent the weekend getting pummeled with a blizzard.

More from Business Insider:

http://uk.businessinsider.com/february-broke-global-temperature-records-2016-3

http://uk.businessinsider.com/extreme-weather-events-increasing-2016-3

Don't miss any update on this topic

Create a free account and access your personalized content collection with our latest publications and analyses.

License and Republishing

World Economic Forum articles may be republished in accordance with the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Public License, and in accordance with our Terms of Use.

The views expressed in this article are those of the author alone and not the World Economic Forum.