premise: New York crude oil futures fell below 56 dollars Friday as concern over supply eased.
  New York's main contract, light sweet crude for delivery in December, which expired Friday, fell 45 cents to close at 55.81 dollars a barrel, the lowest settlement price since June 15, 2005, after hitting 54.86 dollars.
  In London, Brent North Sea crude for delivery in January gained 45 cents to settle at 58.99 dollars a barrel.
  This winter in northeast United States, the world's largest consumer of heating fuel, is warmer than normal till now. Moreover, the weather in northeast would be warmer than normal from December until February, the U.S. National Weather Service said on Thursday. The warmer winter could boost the distillate stockpiles and weaken the fuel prices.
   Why did New York's light sweet crude close at 55.81 dollars a barrel?
hypothesis: concern over supply eased