Anyone who is already anticipating a cold winter is standing on extremely slippery ice

Anyone who is already anticipating a cold winter is standing on extremely slippery ice

It is called again: Elfstedentocht. On social media, meteorologists announced a rare cold in January. “Probably the coldest since 1823”, Written by Mark E. Botto, who presents himself as a strategist for meteorology.

As the Earth continues to warm, the desire to snowboard appears to be increasing as well. And then everything catches the eye. It’s unusually cold in Sweden for a week and a half. Is this a harbinger? And in our country, the first snow that remained for a while fell this week. Can skates really get off the grease?

Predicting the weather for January and February in mid-December is usually difficult. The uncertainties are too large to make meaningful statements. Unless you’re dealing with a phenomenon that casts a shadow over the next several months. This appears to be the case now. La Niña has been going on since September. It is the counterpart of El Niño. Together they make up the so-called ENSO, El Niño-Southern Oscillation. It is a complex phenomenon in the equatorial Pacific. El Niño and La Niña occur infrequently, usually once every two to seven years, but sometimes for two consecutive years, as is the case now with La Niña. Both influence the weather in large parts of the world for months in their own way. “La Niña, for example, is causing very dry weather in East Africa,” says Diem Cuomo, Professor of Climate Extremes and Social Risks at the Free University. “There is a food crisis there.”

Weak influence in Europe

La Niña also greatly affects the weather in the United States. Mike Halpert, deputy director of the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center, wrote: At the end of November a blog about. Based on seventy years of data, he examined the twenty strongest cases of La Niña – the current wave is at the bottom of this range in terms of strength. In the southern United States, especially around the Gulf of Mexico, there is a 70 to 80 percent chance of relatively dry weather next winter. In the northwest, in the Great Lakes region and in the Ohio Valley, there is a greater chance of rain. And in the northwest there is a greater chance of cold weather. Halpert wrote that the effect of La Niña on winter temperatures in the United States is less clear than its effect on precipitation.

“But for Europe, the effect of La Niña is very weak,” says Tim Stockdale. master realm The European Center for Medium Range Weather Forecasts (ECMWF) in reading. “Because Europe is far from the equatorial part of the Pacific Ocean.” In addition, Cuomo adds, Europe’s weather systems are relatively complex and chaotic. For example, you do not have two jet streams, one subtropical and one northern, which both affect the weather on Earth from a height of 9 to 10 kilometers. So there are more factors. “This makes Europe the most difficult continent to predict weather,” Cuomo says.

In any case, the World Meteorological Organization does not expect a cold winter in Europe. exactly the contrary. in a Press release on November 30 Estimated chance of 50 percent above normal Temperatures. So just warmer than average. Areas likely to be relatively cold include the northwestern United States, Australia, Southeast Asia, and large parts of India.

The weak relationship between La Niña and cold winter weather in Europe is also reflected in the Dutch statistics, says Michel van Wiel of the National Institute for Media Professionals. puts something in the mail. Van Weyl wrote: “The last really cold winter months we had were January 1979, January 1985, February 1986, January 1987.” In 1979 there was no La Niña and no El Niño, then El Niño was “neutral”. In 1985 La Niña appeared, in 1986 it was neutral, and a year later El Niño appeared. In 1996 and 2012, it “was not possible” to tour eleven cities. In both years there was talk of La Niña. Overall, Van Weyl writes, “In the past forty years, there appears to have been no relationship between the coldest winter months in the Netherlands and the condition of the ENSO.”

Wide Range

But what is this Twitter claim – arguably the coldest winter since 1823 – based on? The tweet refers to an analysis by the ECMWF. Can Tim Stockdale explain? He later writes in an email that he has a doubt. The ECMWF uses slightly different climate models for its predictions, the so-called band members. Their results vary, so if you put the results together, you get a wide range of possibilities. “It reflects the uncertainty.” Every visitor to the ECMWF website can start with these 51 models. You can also choose. Stockdale wrote that the tweeter appears to have used only one member of the band. No. 23, to be exact. “It does show that very cold winters are possible. But it in and of itself says nothing about the possibility of that happening.”

Is there absolutely nothing to be said about a possible cold winter, and a tour of eleven cities in 2022? “It’s still too early for that,” Van Weyl says. In general, you can say that the chance of a tour of eleven cities decreases with global warming. Despite this, a period of very cold weather can still occur from time to time. According to Daniela Domizen, professor of atmospheric forecasting at ETH in Zurich, these periods now last at most “from a few weeks to a month.” “One of our only chances in a period like this” is when the polar vortex collapses, she says. The polar vortex, also called the polar vortex, is a strong westerly wind in the stratosphere, the layer of air at an altitude of 10 to 50 kilometers. Sometimes the polar vortex is turbulent and the stratosphere heats up locally very strongly within a few days, sometimes up to 50 ° C. This phenomenon becomes a Sudden warming of the stratosphere (SSW). Sudden warming runs downhill, first reaching the jet stream at an altitude of 9-10 km. Thus, the jet stream, which is the boundary between warm southern air and cold northern air, can become more undulating. On Earth, this can, in turn, cause the tongues of cold air to swell southward. This year, such an SSW happened in early January. in the Netherlands He drove it in early February Up to a week of freezing cold. Blizzard Darcy cared For the first nationwide code red since 2012. Also in February 2018, SSW caused very cold weather in Northern Europe.

Read about the sudden warming in the stratosphere last year: Tragic phenomena over the North Pole

When SSW occurs in the Northern Hemisphere, it is often in January and February. But can you predict if such an SSW will occur? “It can only be done a few days in advance,” Dumison says. Thus, the chance that large areas in the mid-latitudes will be exposed to a cold wave is much greater. But exactly what areas are still uncertain.

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