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What is La Niña, will it change Europe's weather and will it cause problems?

What is La Niña, will it change Europe's weather and will it cause problems?

La Niña is the 'counterpart' of El Niño that caused drought and deadly heat in 2024.

The 'long-awaited' La Niña has finally arrived, but it is weak and meteorologists say it is unlikely to cause as many weather problems as usual.

Experts have been waiting for the arrival of the climate phenomenon since last spring, but finally, the cooling of waters in the central equatorial Pacific Ocean was confirmed in early January by the National Oceanic Atmospheric Administration (NOAA).


Meanwhile, El Niño ended in June last year after an unusual three-year stretch.

Lars Lowinski, a meteorologist at Weather & Radar, says that forecasts for the 2024/25 winter season suggested a much more pronounced event starting in the summer.

“However, in reality, it took many more months, with a clear signal only appearing in December 2024, and it is quite weak compared to what we saw between late 2020 and 2023,” he says.

And his late appearance is likely to be the subject of much research.

Experts at NOAA are already wondering whether the delayed arrival of La Niña may have been influenced or even masked by warming of the world's oceans.

What is La Niña?

The El Niño Southern Oscillation (ENSO) is an alternating pattern of sea surface temperature and atmospheric changes in the tropical Pacific Ocean.

Last year brought drought, food shortages and deadly heat to parts of the world.

La Niña is a phase of this cycle, characterized by cooler than average sea surface temperatures in the east-central Equatorial Pacific.

The opposite end of this sea surface temperature fluctuation, El Niño, features warmer-than-average surface water.

ENSO is a seasonal phenomenon, meaning it lasts for several months in a row, bringing atmospheric changes that affect weather patterns worldwide.

It can change global temperatures, as well as rain or snow patterns in usually relatively predictable ways.

La Niña tends to lower global temperatures, bringing drier weather to the southern and western parts of the Americas. In Indonesia, northern Australia and southern Africa, it brings wetter weather.

It usually brings even more hurricanes to the Atlantic, but meteorologists predict that this phase will disappear by summer, when the worst of the season begins.

What does La Niña mean for the weather in Europe?

Lowinski says the "biggest signal" of La Niña in Europe can be found during the winter.

This is due to large-scale weather patterns in other parts of the world interacting with those closer to home.

In this regard, two different areas in the Pacific are being monitored: the Central Pacific (CP) and the Eastern Pacific (EP).

It is important to distinguish between the two, because what is happening in these “two basins” has different impacts on our weather.

"If the strongest cold anomaly during La Niña is in the PE region, the North Atlantic and Western Europe region tends towards weaker storms or blocking low and high pressure systems that often lead to drier and sometimes colder conditions," he says.

This is what happens in theory, Lowinski explains, but "other big players" can influence our European weather such as the NAO, as well as winds in the stratosphere near the equator.

Furthermore, current forecasts suggest a return to neutral conditions before summer 2025, so there are likely to be no strong trends this time around. /Telegraph/