A “bomb cyclone” is expected to strike the Midwest and the Plains this week, making it the second big storm of its kind to hit the Plains in less than one month, CNN reports. The bomb cyclone—a winter-like storm with plummeting atmospheric pressure that typically forms off the East Coast as a nor’easter—is expected to move in on the Plains by Wednesday. Temperatures there are projected to drop overnight by nearly 40 degrees in 12 hours, while storm warnings are being issued from the Rockies to the Great Lakes. Much of the potentially affected areas have already seen warm spring weather this week, including Denver, where it reached 78 degrees on Tuesday. Bomb cyclones tend to bring about a wintry mix of snow and sleet—but it’s rare to see one, let alone two, form inland.