!!THIS CASE WAS MODIFIED ON MARCH 8, 2006!! On August 29, 2004, about 1415 eastern daylight time, an Embraer EMB-135KL, N810AE, operated by American Eagle Airlines as flight 4568, was undamaged following an encounter with turbulence near Clyde, New York. There were no injuries to the 2 certificated airline transport pilots and 16 passengers; while 1 flight attendant was seriously injured. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the scheduled passenger flight, which originated at Toronto/Pearson International Airport (CYYZ), Toronto, Canada, destined for Boston/Logan International Airport (BOS), Boston, Massachusetts. The flight was conducted under 14 CFR Part 121. According to an overview report provided by the operator, the airplane was in cruise flight at flight level 290, when the captain observed a storm about 25 to 50 miles ahead. He then made a cabin announcement to fasten seatbelts, and advised the flight attendant via interphone to take her seat. While the flight attendant was on the phone, the airplane encountered severe turbulence, and she fell to the floor. A beverage service cart subsequently fell on her legs, resulting in serious injury. The captain then elected to divert the flight to Albany International Airport (ALB), Albany, New York so the flight attendant could receive medical attention.