La Niña: Good or Bad?

October 13, 2016
La Niña

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Here’s the news – La Niña, that cool pool of water in the Tropical Pacific, is back.

It’s baaaack! La Niña has returned to the Pacific.  Source: NOAA

Here’s the question: Is that good or bad news?

Here’s the answer: It’s good news for the East Coast and not for Texas. It’s great news for a mellow autumn and rough news for mid-winter cold. It’s good news for retailers and ski resorts, it’s bad news for Christmas air travel. In short, it is a mixed bag of weather.

In the second week of September, the water in the Tropical Pacific became 0.9˚F (0.5˚C) colder than normal. This was low enough that the US weather service officially announced that a new La Niña had begun. Over a million square miles of ocean water were cooling the air above it, making the air dry and cold. This changed the air pressure, which changes wind patterns and weather. When such a huge amount of air is changed, it changes weather all around the globe.

Some of the weather changes were great. In general, La Niñas produce warmer and drier autumns, allowing some of those Midwestern crops that were planted late during the spring floods enough time to ripen. This will help the price of food. Unfortunately, the La Nina will also dry conditions in Texas, which could really use some rain.

La Niña also tend to shift the wind and air pressure patterns that steer Atlantic hurricanes. Since the event began in September, hurricanes have been shooting up the Atlantic Ocean, rather than skimming the East Coast, like Hurricane Irene. Storms in the Caribbean have gone due east rather than veering north into the Gulf Coast, like Tropical Storm Lee.

La Niñas frequently create global wind patterns that tend to steer Atlantic hurricanes away from US shores. Source: NOAA

La Niñas also tend to better the odds for cool, snowy mid-winters. This may make Christmas air traffic a mess, but it is the answer to skier’s prayers. This tends to increase midwinter clothing sales, a gift to retailers. And it provides a pretty, white Christmas.

Just remember this Christmas, as you watch the snowflakes fall—it all started with some cool water in the middle of the vast Pacific.

 

About This Blog

Are you a weather watcher? Welcome to “Weather Whispers” by James Garriss and until recently, Evelyn Browning Garriss. With expertise and humor, this column covers everything weather—from weather forecasts to WHY extreme weather happens to ways that weather affects your life from farming to your grocery bill. Enjoy weather facts, folklore, and fun!

With heavy hearts, we share the news that historical climatologist and immensely entertaining Almanac contributor Evelyn Browning Garriss passed away in late June 2017. Evelyn shared her lifetime of weather knowledge with Almanac editors and readers, explaining weather phenomena in conversation and expounding on topics in articles for the print edition of The Old Farmer’s Almanac as well as in these articles. We were honored to know and work with her as her time allowed, which is to say when she was not giving lectures to, writing articles for, and consulting with scientists, academia, investors, and government agencies around the world. She will be greatly missed by the Almanac staff and readers.

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