Thunderstorms hovered over New York airports on Saturday. LaGuardia took a hard blow. The FAA imposed a temporary ground stop on LGA, Newark, and JFK. Officials pointed to a staffing issue. They removed it fast. But the damage was done. Hundreds of flights at LaGuardia never left the ground . Nationwide, 1,191 flights ran behind schedule. Another scores of got canceled . Delta took the hardest hit. Airlines counted over a thousand disruptions in just two days . A line of rough weather kept pounding its main hub.