Gather los niños!: Understanding the major players of weather and climate variation

You’ve probably turned on the TV, changed the channel to the news, and checked the weather.

You’ve probably heard the weatherman (or woman) say something about “El Niño.”

And then you scratch your head in confusion.

“Extra, extra, read all about it!” El Niño is happening now.

While we were all waiting for Santa in 2015, I’m sure you recall hearing about El Niño on the news; actually most of us on the East Coast were waiting for Santa in T-shirts and shorts. Scratching our heads, we were wondering why the weather was so bizzare in December and took to social media to “praise” or “vent” to discuss the weather. (I dare you to check social media and not run into a post about the unusual weather in December.)

Photo Credit to SNAP Assembly: 

Photo Credit to SNAP Assembly: 

Temperatures during Christmas week of 2015. The 

Temperatures during Christmas week of 2015. The 


So why was this? Many meteorologists and weather forecasting officers blamed it on El Niño. For example, Brian Clark Howard from National Geographic wrote an interesting article about it here:

So why were (and still are) the weather people talking in Spanish?

“El Niño” means “little boy;” in religious terms, it also refers to Christ Child.

In weather terms, El Niño refers to an unusual climate pattern where the water in the Pacific Ocean near the equator gets warmer than usual. According to the National Oceanic and Atmospheric Administration (NOAA), El Niño “results from the interaction between the surface layers of the ocean and the overlying atmosphere in tropical Pacific…. It involves unstable air-sea interaction and planetary scale oceanic waves.”

This causes a disruption of the ocean-atmosphere system in the tropical Pacific, leading to changes in weather around the world.

Wait a second; what does the ocean have to do with the weather?

Guest poster Molly Roberts mentioned the connection between the Ocean and the weather with her post on ‘Ocean Monitoring.’ Read more about it here!

The world’s ocean is crucial to heating the planet. The majority of the sun’s radiation is absorbed by the ocean. The ocean also helps to distribute heat around the globe. Ocean water is constantly evaporating, increasing the temperature and humidity of the surrounding air providing the energy to form and fuel rain storms which are then carried by trade winds, often vast distances. In fact, almost all rain that falls on land starts off in the ocean.

Ocean Currents; Encyclopedia Britannica 2007

Ocean Currents; Encyclopedia Britannica 2007

Ocean currents, the movement of ocean water, act like a conveyor belt, transporting warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics. Thus, currents regulate global climate, helping to counteract the uneven distribution of solar radiation reaching Earth’s surface. Without currents, regional temperatures would be more extreme—super hot at the equator and frigid toward the poles—and much less of Earth’s land would be habitable.

Okay, so why was I wearing shorts in December?

Global wind Patterns;

Global wind Patterns;

In a normal year, strong winds near the equator, called trade winds, blow East to West, pushing the warm surface water near South America westward across the Pacific Ocean toward Southern Asia. Warmer waters bring humid and hot conditions, typical climates for countries like Indonesia and Thailand. As the winds continue to blow east to west in the Pacific Ocean, the cooler water underneath rises up toward the surface of the ocean near South America; this is called upwelling. The cooler water doesn’t contribute as much moisture to the atmosphere, so it is generally pretty cool and dry in places like Chile and Peru.

This also creates strong winds called the Westerlies in higher latitudes causing these cool dry winds to blow from West to East.

However, during an El Niño year, trade winds become weaker due to physical processes occurring between the air and sea, causing a build of warm waters along the Pacific Coast of South America. This causes the whole ocean to warm as well.  Warm waters add extra heat to the air, which causes the air to rise, causing unsettled weather, like intense rainstorms. These physical processes can cause changes to typical weather conditions like temperature and rainfall.

And the continuing Westerlies blowing from West to East also brings that unsettled weather across the country.

Howard, from National Geographic, wrote: “Not only does El Niño bring warmer temperatures, but it’s also been forcing the jet stream farther to the north. Normally, that band of strong, high winds brings colder air and more moisture down to lower latitudes. This year, El Niño and wind patterns combined to push heavy snow to places such as Denver while still leaving areas further east relatively balmy.“

Fishfill May 2011:

Fishfill May 2011:

The blob of warm water also cuts off the cold-water upwelling from lower-levels of the ocean off the Pacific Coast of South America. Without upwelling, there is less cool water and nutrients, which are important for the fisheries. Thus when an El Niño happens, the fish that live in the normally cooler waters off the coast of South America move away or die.

The South American fishermen call this condition of warm coastal waters and poor fishing "El Niño" meaning "the Christ Child," because, in the occasional years it comes, it occurs during Christmas time.

Warm water build-up, unsettled weather, fish die-off, South America, Christmas time. See the connection?

Check out this cool animation of how El Niño works

What are the effects of El Niño?

These are only some of the things that El Niño can do:

  • Cooler and wetter weather to the southern United States
  • Warmer weather to western Canada and southern Alaska
  • Drier weather to the Pacific Northwest
  • Cooler weather to northern Canada
  • Wetter weather to southern California
  • Effects show up most clearly during wintertime
  • Linked with drought not just in parts of Latin America but in southeastern Africa, South Asia, Indonesia and Australia.
  • El Niño usually brings a warm winter to the northern USA from the Pacific Northwest across to the Midwest and sometimes the Northeast
  • Reduction in the number of hurricanes that form over the Atlantic Ocean, especially strong ones

Don’t forget the girls! La Niña

There is also a phenomenon called La Niña. And you can guess that ‘La Niña’ means, little girl.

La Niña is sort of the opposite of El Niño. While an El Niño refers to a pattern characterized by the tropical Pacific’s warmest water spreading eastward to the coast of South America, La Niña refers to times when waters of the tropical Pacific are colder than normal. According to scientists, La Niña cycles generally create a more active hurricane season in the Atlantic.

Well, we’ll see what the rest of the year will bring in weather! Happy New Year!