Severe thunderstorm watch in effect for Orleans, WNY

This map from the National Weather Service shows a vast area of New York is in a severe thunderstorm watch.
Orleans County and much of western central and northern New York are under a severe thunderstorm watch until 11 p.m. today.
The watch is already in effect. The Weather Service warns that thunderstorms will increase through the afternoon.
“Isolated thunderstorms are developing in an unstable airmass across the region early this afternoon, the Weather Service said. “Expect these thunderstorms to expand in coverage and intensify through by mid to late afternoon.”
The storms could bring gusts over 50 miles per hour and tropical downpours.
“Flooding could occur if multiple storms move over the same area,” the Weather Service said.