This weekend’s major winter storm is bringing what’s called a “cold wave” — a meteorological event where temperatures plummet for several days. Bouts of cold like this one have their origins at the North Pole, where icy air typically stays.
But sometimes, waves of air in the atmosphere collide with the polar vortex — the spinning band of strong, cold wind that keeps Arctic air in place — and the polar jet, a similar air current that flows at a lower altitude. Those collisions can cause chilly Arctic air to spill over into lower latitudes.
These dynamics are harder to model than other weather phenomena, such as heat waves, because of how quickly cold snaps can form. Conventional forecasting tools often struggle to track all the factors at work: interactions between the Arctic Ocean, the ice above it, and the sky influence weather patterns around the world. There are also other sources of variability, like the periodic warming and cooling pattern in the central Pacific Ocean known as the El Niño-Southern Oscillation.
“It always ends up colder than the models initially predict, and the models are always playing catchup,” said Judah Cohen, a research scientist at the Massachusetts Institute of Technology studying weather forecasting.
But forecasting is getting more accurate. New AI-powered models can account for more variables, which in turn yields better medium-range forecasts — predictions that look at the weather two to six weeks in advance.
Cohen’s team trained a model on decades of observations across the Northern Hemisphere, for instance. They found that there were really far-flung variables at work, from weather in Eurasia in October to ocean temperatures in parts of the Arctic like the Kara Sea. As early as November, he started raising the alarm that a blast of extreme cold was heading toward the United States.
Naturally, climate change and the Trump administration may both complicate the situation. The exact extent to which human activity is altering cold snaps isn’t known. In general, the planet is heating up, and winter temperatures are rising faster than summer temperatures are. But in certain areas and at specific times, there are still periods of intense cold, and some evidence suggests that warming in the Arctic is contributing to these cold weather spillovers.
There are, however, other scientists who think that Arctic warming doesn’t play a big role in cold weather at lower latitudes and who have found that global warming has led to fewer extremely cold temperatures. So this is, as scientists say, an area of active research.
On top of all that, the US is cutting back on a lot of its scientific research, especially around climate change. The Trump administration has specifically targeted the National Center for Atmospheric Research, one of the best places in the world conducting weather and climate predictions. And job cuts across the government have already led to less collection of the raw data that informs weather models. So at a time when the country needs a better look at the world ahead, the current administration is obscuring the view.
Read Umair’s full story here.
