La Nina is officially coming

We're officially on a La Niña watch. 

The National Oceanic and Atmospheric Administration (NOAA) said Thursday that it's 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 warmer 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:

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 could be a much different change of pace compared with what El Niño did to the US last 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.