Neel Dhanesha/Nieman Lab

A severe storm swept across the central U.S. overnight on May 16, bringing tornadoes to a region that has already been ravaged by them this spring. At least 27 people in Missouri, Kentucky, and Virginia have died, dozens more have been injured, and thousands of buildings have been damaged or destroyed.It’s one of the most devastating storms to hit the region this tornado season, and more are likely to come. But as summer — which tends to be disaster season — approaches, meteorologists are raising the alarm over a growing crisis: It’s getting harder to predict the weather, and the reasons are largely political.