Human-driven changes in the westerly winds are bringing hotter and drier springs to the American Southwest, according to new research from The University of Arizona in Tucson. Since the 1970s the winter storm track in the western U.S. has been shifting north, particularly in the late winter. As a result, fewer winter storms bring rain and snow to Southern California, Arizona, Nevada, Utah, western Colorado and western New Mexico. ‘We used to have this season from October to April where we had a chance for a storm,’ said Stephanie A. McAfee. ‘Now it’s from October to March.’ The finding is the first to link the poleward movement of the westerly winds to the changes observed in the West’s winter storm pattern. The change in the westerlies is driven by the atmospheric effects of global warming and the ozone hole combined. ‘When you pull the storm track north, it takes the storms with it,’ said McAfee, a doctoral candidate in the UA’s department of geosciences. ‘During the period it’s raining less, it also tends to be warmer than it used to be,’ McAfee said. ‘We’re starting to see the impacts of climate change in the late […]