How will the third straight year of La Niña affect the winter weather in the US?
Forecasters are warning of cold patches on the surface of the Pacific Ocean which could prompt unusual weather trends in the US and further afield.
For the third year in a row meteorologists are warning that La Niña, a Pacific Ocean weather system, will bring strong winds across the world. This is the first time this century that La Niña has been recorded in three consecutive years, a major cause for concern amongst meteorologists.
“It is exceptional to have three consecutive years with a la Niña event,” said World Meteorological Organization (WMO) Secretary-General Petteri Taalas in a statement.
“Its cooling influence is temporarily slowing the rise in global temperatures – but it will not halt or reverse the long-term warming trend,” he added.
La Niña is a strong natural force that occurs when strong winds push warm air on the surface of the Pacific Ocean from South America towards Asia. Once the warmer, less dense surface layer has been shifted from the Pacific Ocean cooler water rises to the top, creating a cycle of water movement that brings with it changeable weather conditions.
We are currently in a “triple-dip” cycle of La Niña, meaning that the phenomenon has been recorded in three consecutive years. It began in September 2020 when surface water on the Pacific Ocean was cooler than average.
During La Niña the trade winds are stronger than usual, speeding up and intensifying many of the meteorological trends that we are used to seeing in other years.
What does La Niña mean for weather in the US?
La Niña brings cooler-than-average waters in the central Pacific Ocean but the effects for weather trends can be felt across the world, such is the strength of the Pacific trade winds.
However the consequences will vary greatly across the planet and even across the United States. In the Northwest regions there will be unusually dry conditions, while the Southeast and Mid-Atlantic will also see warmer-than-average temperatures. These consequences are also felt further afield, Taalas explains.
“The worsening drought in the Horn of Africa and southern South America bear the hallmarks of La Niña, as does the above average rainfall in South-East Asia and Australasia,” Taalas said in the report. “The new La Niña Update, unfortunately, confirms regional climate projections that the devastating drought in the Horn of Africa will worsen and affect millions of people.”
Having a third consecutive year of La Niña is concerning because a single cycle can last up to nine months, according to ABC News. The trend normally begins in early fall and can continue throughout the northern hemisphere’s winter.