30-day forecast? Weather prediction might be able to look beyond 2 weeks

sciencehabit writes: It’s a truism almost as old as modern weather prediction: Any forecast beyond 2 weeks will fall apart because of the way tiny perturbations compound in the atmosphere. The 2-week limit, grounded in chaos theory and notions of the “butterfly effect” from the 1960s, has been handed down from generation to generation, says Peter Dueben, head of earth system modeling at the European Centre for Medium-Range Weather Forecasts, the world’s leading forecaster. “It’s basically a God-given rule.”

But even the gods can be wrong.

Using an artificial intelligence (AI) weather model developed by Google, atmospheric scientists have found that forecasts of 1 month or more into the future might be possible. “We haven’t found a limit to how far you can go out,” says Trent Vonich, a doctoral student at the University of Washington (UW) who led the work, released late last month as a preprint on arXiv. “We ran out of memory first.”

The result has caused a stir ever since Vonich and Gregory Hakim, his adviser, spoke this year at the annual meeting of the American Meteorological Society, says Amy McGovern, a computer scientist and meteorologist at the University of Oklahoma. Using powerful computer models, researchers have already pushed meaningful forecasts out to about 10 days, coming ever closer to the 2-week limit. Showing this limit can in principle be broken “means that AI will be able to do this someday, which is really exciting,” she says.