Natural gas jumped to a 16-week high in New York, capping its biggest weekly gain in almost two months, on speculation that a late cold blast heading into spring will boost heating demand.Gas rose 1.6 percent as Commodity Weather Group said below-normal temperatures in the North over the next five days will spread across the East from Wednesday to March 29."You have the continuation of colder weather expected into the balance of next week, and it looks like the start of April might also be cooler," said Teri Viswanath, director of commodities strategy at BNP Paribas. "With that consistent pattern of colder weather coupled with a heavier-than-anticipated storage withdrawal last week, you are seeing some follow-through buying."Gas for April delivery rose 6 cents to $3.87 per 1,000 cubic feet on the New York Mercantile Exchange, the highest settlement since Nov. 23. Prices climbed 6.7 percent this week, the fourth straight gain and the biggest weekly increase since Jan. 18. Prices are up 70 percent from a year ago.About 50 percent of U.S. households use gas for heating, according to the Energy Information Administration, the Energy Department's statistical arm.Gas demand typically slumps between the peak heating-demand season and before hot weather drives power demand to run air conditioners.Gas stockpiles fell by 145 billion cubic feet to 1.938 trillion in the week that ended Wednesday, declining below 2 trillion for the first time since May 2011, the EIA said.