On January 28, 1994, about 1230 eastern standard time, VRBNK, an Airbus A-300, operated by Air Jamaica, a scheduled, international, passenger flight from Baltimore, Maryland, to Montego Bay, Jamaica, encountered turbulence at flight level 310 in cruise flight. Visual meteorological conditions prevailed at the time and an IFR flight plan was filed. The airplane was not damaged and one passenger received serious injuries. Two hundred eight were not injured. The flight originated from Baltimore, Maryland, about 1115 the same day. Air Jamaica personnel reported the flight was cruising at flight level 310 clear of clouds when the airplane encountered one jolt of turbulence. The one passenger who received a fracture of the left leg was walking in the aisle at the time. The seatbelt sign was illuminated and the flightcrew had made an announcement for all passengers to be seated and attach their seatbelts The flight diverted to Miami, Florida, and the passenger was evacuated to a local hospital. Evaluation of the weather in the area revealed that a combination of upper level high winds and radiative activity may have produced isolated turbulence.