Air carrier departure from JFK Runway 31R voiced concern regarding the simultaneous operations from Runway 22R; claiming a jolt was received from traffic in position on 22R during takeoff requiring quick counter actions on the part of the flight crew.

Narrative

JFK Tower cleared us for takeoff on 31R; Kennedy 1 Departure (Breezy Point Climb). After our takeoff roll the Tower cleared a heavy aircraft into position on 22R Intersection YA and hold at idle thrust at an intersecting runway. At around 100 knots we received a pretty good jolt from his thrust buffet. Quick left rudder and left aileron was used to counteract the thrust buffet. We notified ATC Departure to relay the message to JFK Tower about the event. ATC should not position and hold someone on 22R YA after clearing someone for takeoff on 31R. The risk is too high and is only dependent on the other aircraft not using more than idle thrust or turning his aircraft. Of course the best way is to not have an aircrafts thrust directly in the path of another aircraft taking off. However; it would seem that it would work better if the aircraft was stopped in position and hold on 22R; YA and holding at idle thrust; then clear the aircraft for takeoff on 31R. I think that this aircraft might have been in his turn for lining up with the Runway 22R YA. This could cause a dangerous situation if your aircraft had an engine failure or steering problem at that time or just a pilot that does not react quickly enough. Safety should come before expeditious flow of traffic.