Increased heating demand expectations in the latest forecasts helped extend natural gas futures gains in early trading Tuesday. After rallying 22.6 cents in the previous session, the December Nymex contract was up another 15.8 cents to $5.175/MMBtu at around 8:45 a.m. ET.

NGI Morning Natural Gas Price & Markets Coverage

Recent run-to-run volatility from the major weather models continued overnight, this time with both the American Global Forecast System (GFS) and European models adding heating degree days (HDD) to the outlook over the next two weeks, according to NatGasWeather.

“On cue, the overnight weather data flipped back colder, with the GFS adding 8-9 HDD on colder trends across the northern U.S.,” the firm said. “The European model was warmer for this weekend into the start of next week but colder Nov. 24-30,...