Natural gas prices made their biggest one-day gains since June as colder forecasts and a smaller-than-expected storage addition boosted prices. Prices for the front-month December contract settled up 10.2 cents, or 4.5%, at $2.364 a million British thermal units on the New York Mercantile Exchange. It was the biggest one-day percentage gain since June 15. Gains accelerated after the U.S. Energy Information Administration said producers added 52 billion cubic feet of natural gas to storage in the week ended Oct. 30. That is 6 bcf less than the average forecast of 17 analysts and traders surveyed by The Wall Street Journal. The weekly report is looked to as a leading indicator of supply and demand. A lower-than-expected addition would suggest that supply was smaller or demand was larger than expectations. Futures for December delivery recently traded up 6.8 cents, or 3%, at $2.33/mmBtu on the New York Mercantile Exchange. […]