UPDATE 3-Cold forecast drives U.S. natgas futures up for 2nd day

* Coal switching, nuclear plant outages lend some support * Cold trend may continue through most of March * High inventories, record production limit upside By Joe Silha NEW YORK, Feb 25 (Reuters) - Front-month U.S. natural gas futures, shrugging off concerns about high supplies, ended higher on Monday for a second straight session amid expectations that chilly weather forecasts for most of the next two weeks should increase heating demand. Despite the two-session run up, t