Extreme volatility returned to U.S. natural gas futures on Jan 14, with the front-month up over 8% on forecasts for much colder weather and more heating demand than previously expected through the end of January.

In their latest midday predictions, meteorologists said the weather would turn intensely cold starting Jan. 19 and remain frigid across much of the country through at least the end of January.

Front-month gas futures for February delivery on the New York Mercantile Exchange were up 26.5 cents, or 8.6%, at $3.364 per million British thermal units at 7:23 a.m. EST (1223 GMT), their highest since Dec. 28.

That puts the contract on track for its biggest daily percentage gain in almost four weeks.