What is La Niña in simple terms?
La Nina refers to the periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific. Typically, La Nina events occur every 3 to 5 years or so, but on occasion can occur over successive years. La Nina represents the cool phase of the El Nino/Southern Oscillation (ENSO) cycle.
What causes the La Niña phenomenon?
La Niña is caused by a build-up of cooler-than-normal waters in the tropical Pacific, the area of the Pacific Ocean between the Tropic of Cancer and the Tropic of Capricorn. Unusually strong, eastward-moving trade winds and ocean currents bring this cold water to the surface, a process known as upwelling.
What is La Niña and what does it mean for our weather?
Per NOAA, La Niña is defined as cooler than normal sea-surface temperatures in the central and eastern tropical Pacific Ocean that impact global weather patterns. These cooler sea-surface temperatures occur because the negative phase of ENSO results in faster trade winds over the central Pacific Ocean.
What is the effect of La Niña?
La Niña intensifies the average atmospheric circulation—surface and high-altitude winds, rainfall, pressure patterns—in the tropical Pacific. Over the contiguous United States, the average location of the jet stream shifts northward. The southern tier of the country is often drier and warmer than average.
What are La Niña conditions?
“During a La Niña event, ocean water from off the coast of South America to the central tropical Pacific cools to below average temperatures. The unusually cool water in the eastern Pacific influences the Walker Circulation and suppresses cloud, rain, and thunderstorms.
What does a La Niña winter mean for the South?
Typically La Nina winters feature a lot of weather and temperature variability with large swings from mild to very cold and from tranquil to quite stormy An average La Nina pattern will favor warmer and drier than average weather over the southern United States and Southeast, with colder than typical weather over the …
Does La Niña mean more rain?
The current La Niña may also be weaker than the one last summer. The strength of La Niña is determined by how much the sea surface temperature deviates from the norm. Typically, the stronger an event, the more rainfall.
What is La Nina weather in NZ?
In New Zealand, northeasterly winds tend to become more common during La Niña events, bringing moist, rainy conditions to northeastern areas of the North Island and reduced rainfall to the lower and western South Island. Warmer than average air and sea temperatures can occur around New Zealand during La Niña.
What are the effects of La Nina?
La Nina is a phenomenon occurring in the Pacific Ocean that can impact weather around the world. It involves stronger winds pushing warm water from the east of the ocean to the west. This can cause changes in wind and pressure patterns, along with temperature and rainfall, as a knock-on effect is felt around the globe.
What is El Nino and La Nina phenomena?
El Nino and La Nina are two opposing weather cycles – which dictate the biggest fluctuation in the Earth’s climate system. The phenomena occur in the Pacific Ocean , but can bring huge changes in temperatures across the globe. El Nino is the warming of sea surface waters in the eastern Pacific, towards the coast of South America.
What does La Nina cause?
La Niña is associated with the higher than normal rainfall in the central Andes (South America), often causing catastrophic flooding. Veryheavy rains and flooding in the Philippines, Brazil, Malaysia, and Indonesia are also largely determined by the La Niña.
How is El Nino and La Nina difference?
It means La Nina occurs due to the fact that the surface of the ocean has its temperature reduced by few Celsius below normal. One of the important differences between La Nina and El Nino is in connection with the frequency of their occurrence. It is said that El Nino occurs more frequently than La Nina.