Western New York was placed under a severe thunderstorm watch by the Storm Prediction Center of the National Weather Service just after 4 p.m.
Forecasters said strong to severe wind gusts could result from some storms late this afternoon into early evening.
Weather Service radar showed thunderstorms racing across southern Ontario just before 4 p.m. Radar indications suggested hail was falling.
There was also reports of substantial lightning associated with the storms.
A warm, moisture-laden airmass ahead of a cold front will provide the fuel for today's storms, forecasters said.
The Storm Prediction Center estimates the chances for severe winds at 15 percent, hail at 5 percent and even a 2 percent chance for a tornado.
"Some initial convection may form by mid-afternoon along a pre-frontal trough in the areas of quickest destabilization east of the lower Great Lakes, where isolated damaging winds will be possible," forecasters at the Storm Prediction Center said.
It added: "Damaging winds will be the main threat through downward momentum transfer, though vertical shear and moisture will be sufficient for a low-end tornado threat."