ZBW Controller experienced a conflict event when unusually strong East wind conditions required the issuance of a circle to a JFK arrival to lose altitude that resulted in the proximity event.

Narrative

This was a very unusual situation. The winds were very strong out of the East due to a nor'easter. As a result; the ground speeds of JFK arrivals were in excess of 470 knots; or at least 50 knots greater than is customary. Air Carrier X; as a result; was hung up at FL200; above a northbound aircraft; slow-moving; at FL190; also a very unusual occurrence. The workload in the sector; which had been minimal; increased suddenly with 5 almost simultaneous departures from 4 different airports. By the time a D-Side controller was assigned to help; the PE (proximity error) was bound to happen. The final complicating factor is a 'cone of silence issue'. Most of the Clipper Sector is single-site adapted; 3NM separation below FL180. The RADAR sort box directly over the RADAR site is like a square island of airspace which is not eligible for the 3NM separation; and the old standard of 5 miles is in use. The other aircraft involved a type JS31; was one of these departures from BDR. I was able to climb this aircraft to 16;000 and turn him southbound while he was still west of CCC. In the meantime; Air Carrier X was too high (FL200) to make a normal hand off to JFK approach (@12;000). A decision was made to issue a 360 degree left turn to Air Carrier X to accommodate his descent. This was accomplished; but as he descended through 16;000; the aircraft; still pushed by the strong easterly winds; got to within 4.59 NM of the JS31; who was not yet at 16;000. He was at 15;500 when Air Carrier X was at 15;100 at their closest proximity. I was too busy at the time to ascertain whether one aircraft was out of 'the square' or not and did not have time to measure the difference between 4.59 and 5 NM. I was informed the next day of the PE; and was told that it was a 'controlled event' since both aircraft were firmly established as moving away from each other at the time of the PE. Obviously; the inability to use 3 mile separation is the overriding issue here. It is; coincidentally; the spot in this sector where 3 mile separation would be the most beneficial. I am told that changing the adaptation from the Riverhead RADAR site to the Islip site would present other problems; and that a fix probably would not be attempted until after the implementation of ERAM (En Route Automation Modernization).