Europe is in the gray area on the map of seasonal forecaster ECMWF. Earlier forecasts occasionally came true, but often they did not. As a result, the predictive power of the forecast in Europe does not exceed the limit of chance. ‘The weather here is strongly determined by the wind direction,’ says climate scientist Peter Siegmund (KNMI). ‘And it is difficult to predict.’
Nevertheless, the new ECMWF forecast (the acronym stands for European Center for Medium-Range Weather Forecasts) made headlines last week. ‘Trembling for severe winter due to energy crisis‘, headlined The Telegraph. ‘Weather forecast: we are going to have a cold winter‘, stated Dragonfly fixed. ‘Europe heading for an unusually warm winter‘, the headline of the French news channel France24 was confusingly correct, based on exactly the same forecast. There are evenabnormally high temperatures‘, according to business magazine Fortune.
‘You see messages like this every year,’ says Siegmund. “Everyone likes to hear these kinds of forecasts. And every provider, especially commercial parties, has an interest in announcing them. But especially with the current gas crisis, I think you should actually exercise restraint and not raise false expectations.’
The reporter of the news in our country was weather agency Weeronline, which says that the forecast for December 60 percent certain is. That forecast: a high pressure area will be located above Europe, increasing the chance of night frost and less precipitation than average. Whether there will be real winter cold depends on exactly where the high pressure area will be located.
But that forecast only covers December, and the chance that it will come true is only 10 percentage points greater than chance, admits meteorologist Jaco van Wezel of Weeronline. ‘Still, we think we shouldn’t keep quiet about this’, he explains the choice to dedicate a message to it on the internet. ‘We did our best to bring the message in a nuanced way. But it then took on a life of its own. The demand for reports about winter, preferably with cold and snow, is always very high.’
Warm water in the Pacific Ocean
The starting point of many of the forecasts is half a globe away, in the Pacific Ocean. There, the sea current will experience a La Niña for the third time in a row in the coming months with 75 percent certainty, a phase in which heated seawater is pushed towards Australia, while the sea off Chile cools down. The result: heat and moisture in Australia, and drought and low-pressure areas in South America.
Like a water bed that someone pushes on, it ripples thousands of miles away in the pressure areas that shape the weather. For the US, the US climate service NOAA expects a ‘typical La Niña winter’, with lots of snow and cold in the north, and extra mild weather and drought in the southern states and along the east coast. There, and especially around the equator, the forecasts are fairly accurate.
A warm, dry winter is expected for Europe, up to 2 degrees warmer than normal. Whereby the ECMWF notes: ‘We observe a high variability over Europe each time we run the model, which underlines the low certainty of the influence of La Niña on Europe.’ Nevertheless, the models regularly arrive at a ‘blockade’ in Europe. That is a persistent high pressure area that forces the dominant wind direction from west to north and would thus provide a supply of cold polar air. Although the models are ‘not fully in line’, it is also emphasized here.
Freezing cold in Ukraine
Also about the course of the winter in Ukraine, where the population is anxious about how cold it will be, the models over the past forty years have been unable to come up with a forecast that was better than if one were to throw a blanket over it. coin would determine. Apart from the already known: Ukraine has a continental climate, with prolonged freezing cold in winter. In any case, the ECMWF’s wobbly forecasts point to a winter with remarkably little snow. In Ukraine, but also in the lower winter sports areas of Poland, the Czech Republic and France.
Siegmund ventures to doubt whether it will ever succeed in capturing the Dutch winter in a reasonably accurate forecast. Existing weather models look no more than two weeks ahead. Looking further into the future is difficult, because the possibilities pile up so fast that computers can’t handle them. ‘You cannot overcome the unpredictability of the weather with your forecasts,’ Siegmund thinks.
Wipe all calculations and forecasts off the table, says Van Wezel, and this is what you’re left with: a warmer winter than average, because the climate is warming. Since 2000, three-quarters of all Dutch winters have been warmer than the long-term average of 3.9 degrees Celsius. ‘That fact alone makes a 75 percent chance of an above-average warm winter,’ he reasons.
Van Wezel points to the winter of 2020-2021, when the ice became thick enough almost everywhere in early February to skate for a few days. ‘Everyone remembers that. But actually much more unusual was how hot it got afterwards, in the second half of that month,’ says Van Wezel. ‘You can see from that: global warming has changed our perception of what ordinary winter cold is like.’