MTECHTIPS- U.S. natural gas futures fell sharply on Tuesday, as a mild start to the winter heating season added to concerns over a deepening supply glut. Natural gas for December delivery on the New York Mercantile Exchange tumbled 13.2 cents, or 4.69%, to $2.684 per million British thermal units by 10:35 AM ET (15:35 GMT), after sliding to $2.671 in early trade. Updated weather forecasting models showed that high pressure weather systems will dominate over the central and southern U.S. this week, resulting in much warmer than normal conditions. Overall, demand for natural gas will be much lighter than normal with the lack of subfreezing temperatures across the eastern U.S. and the Great Lakes-region. Natural gas futures are down almost 12% so far this month as warmer-than-average weather in key gas-consuming regions in the U.S. ignited speculation that a mild winter will curtail demand for the heating fuel and leave a glut of it in storage, weighing on prices next year. Gas futures often reach a seasonal low in October, when mild weather reduces demand, before recovering in the winter, when heating-fuel use peaks. Meanwhile, market participants awaited weekly supply data due on Thursday, which is expected to show a build in a range between 51 and 61 billion cubic feet in the week ended November 4. That compares with a gain of 54 billion cubic feet in the preceding week, 54 billion a year earlier and a five-year average build of 38 billion cubic feet.