Will ‘sudden stratospheric warming’ at the end of this month cause a wintry Christmas and New Year? This is what the weather maps say | Science & Planet

“It is currently changeable for a few days, but towards the weekend we see a core of high pressure strengthening west of Portugal,” said Roose. “It is moving north and will also affect Western Europe during the weekend. Under the wings of this high-pressure area, the wind disappears and we once again have calm conditions in the Low Countries. The chances of fog will increase with slightly lower temperatures. It may even reach a degree of frost during the night. However, there is no snow yet.”

_{Read more below the image}

The weather analyst shakes his head: “No white Christmas for the time being. The first signals for Christmas 2023 already point towards a green edition. The US weather model hints at a strong northern jet stream bringing mild air from the Atlantic Ocean to the British Isles.”

There are some colder solutions available for Christmas within the American weather model, but these are still in the minority, the weather analyst reports. So we don’t immediately expect a carpet of snow and severe freezing temperatures. Although something special seems to be happening in the weather maps according to Roose.

_{Read more below the image}

“Weather experts have been noticing strong signals in both the American and European weather models for some time that there will be significant warming in the stratosphere between December 20 and 30, 2023,” Roose explains. “In itself this is not so exceptional, but it will become so if the warming continues and goes to extremes. If a number of other technical conditions are met, we speak of a so-called ‘Sudden Stratospheric Warming’ in meteorologist language. Translated, that is a sudden warming of our stratosphere. By the way, that is the layer of air above the one we live in, the troposphere.”

“Under normal circumstances, the stratosphere cools down significantly towards the winter period,” Roose explains. “The coldest places are found above the North Pole. There temperatures drop to -80 °C at an altitude of about 10 to 17 kilometers. This creates a new low-pressure area above the North Pole every year, which is called the Polar Vortex. When the sun loses power in the Northern Hemisphere, this low-pressure area becomes stronger and stronger with icy air inside. It usually stays nicely in place, … most of the time.”

_{Read more below the image}

“In rare cases, the polar vortex can be disrupted by factors such as a sudden warming of the stratosphere. And if that happens, the cold air can escape and sink towards the south. Parts of North America, Asia and Europe will then have to take severe cold snaps into account.” Such a warming of the stratosphere can therefore influence the lower air layer, the troposphere, and thus influence the weather in the Northern Hemisphere.

“An enormous warming in the stratosphere is not immediately a safe-conduct for fierce winter weather, but it increases the risk of outbreaks of very cold air from the North Pole,” the weather analyst further explains. For example, last year there was also a sudden warming of the stratosphere. Then a cold shot was not given. “The effects of an SSW are often only felt a few weeks later. The warming in the stratosphere may therefore come too late for a snow carpet during Christmas. We are more likely to see an impact on our weather in January or February of 2024, provided the weather maps get right and there is a sudden warming of the stratosphere.”

‘Polar vortex’ returns above North Pole: what is this? What are the consequences? And will there be a harsh winter? Expert explains (+)

“Avalanches in mountains and flooding in ski villages”: atmospheric river will deliver monthly rainfall to Alps in 48 hours

Risk of winter sting due to warming stratosphere. Is this exceptional? Do we have to worry? Is this a result of climate disruption? Five questions answered (+)