Natural gas prices plunged sharply on Monday, as weather forecasts predicted temperatures across the U.S. would not be as cold as previously thought, dampening near-term demand expectations for the heating fuel. On the New York Mercantile Exchange, natural gas for delivery in February tumbled 12.0 cents, or 3.85%, to trade at $3.007 per million British thermal units during U.S. morning hours, after hitting a daily low of $2.978. Trade volumes were expected to remain light on Monday, with U.S. markets closed for a holiday.