ZNY Controller described an emergency weather altitude deviation over the Atlantic; coordinated via phone patch; the reporter suggesting Traffic Management should be more proactive metering non-RADAR tracks during significant weather periods.

Narrative

An Air Carrier requested a weather deviation 30 [degrees] right of course; I probed deviation request into ATOP and numerous traffic conflictions were depicted. I then examined alternate clearances; climb or descent for deviation; deviation to the other side of course. Due to traffic volume on adjacent airways and traffic on the same airway; there were no deviation options available for the Air Carrier. I advised the Air Carrier unable deviation request due to traffic. The aircraft advised 'We are going to descend 300 FT; flight is declaring an emergency'. Upon receipt of pilot's intentions; I emergency altituded the flight at FL367 and requested a phone patch with the aircraft. On phone patch I advised pilot of traffic in the area and asked what direction and how far he was deviating. Pilot advised deviating 30 right of course at FL367. I advised pilot that I understood he declared an emergency and asked if he needed further help. He stated no and I terminated the patch. I advised the FLM of what was going on. I VHF'd the 30 right deviation into the flights profile. The Air Carrier advised on course at FL370. Recommendation; the ZNY Traffic Management unit should be more proactive in metering traffic on Oceanic Non-RADAR airways when there is weather. There was a significant tropical storm over the ocean a having far-reaching impact on oceanic traffic.