* Front futures end higher for a second day * Extended forecasts revised warmer again * Coming Up: Reuters natural gas inventory poll on Wednesday By Joe Silha NEW YORK, Aug 7 (Reuters) - U.S. natural gas futures ended higher on Tuesday for a second straight day, backed by buying ahead of Thursday's weekly inventory report and slightly warmer revisions to extended weather forecasts. Gas demand perked up this year after prices in the spring slid to 10-year lows below $2 per mmBtu and prompted many utilities to switch from coal to cheaper gas to generate power. Then widespread heat this summer lifted demand further and helped slow weekly inventory builds to below average for 14 straight weeks, pulling a huge inventory surplus down some 47 percent from late March highs. "I think we moved up today ahead of the (EIA) storage number, which should be low relative to the five-year average, and weather still looks supportive from a power generation perspective," said Eric Bickel, analyst at Summit Energy. Front-month gas futures on the New York Mercantile Exchange ended up 5.6 cents, or 1.9 percent, at $2.964 per million British thermal units after trading between $$2.882 and $2.995. Chart traders said the market had gotten oversold and was due for a bounce after a four-day slide late last week drove prices down by more than 10 percent. They noted that the front contract on Monday tested and held support at the 40-day moving average, a sign the down move might be over, at least temporarily. But most agreed the contract needed to close above $3 to set the stage for more upside. Some traders said that as gas prices push above $3, some utilities could move back to coal, slowing overall gas usage and raising the possibility of bigger weekly storage injections. Many remained skeptical of further upside, with peak summer heat likely to fade in a few weeks, and storage and production still running at or near record highs. Private forecaster Commodity Weather Group, in its morning report, noted that both the 6-10 day and 11-15 day forecasts turned warmer overnight. PRODUCTION HOLDS NEAR RECORD In its Short-term Energy Outlook (STEO) on Tuesday, the U.S. Energy Information Administration trimmed its estimate for domestic natural gas production growth in 2012, but still expects output to be up 3.8 percent from 2011's record levels. The agency said it expected marketed natural gas production in 2012 to rise by 2.5 billion cubic feet per day to a record 68.72 bcfd, down slightly from its July outlook that had output this year at 68.98 bcf daily. EIA did say, however, that it expects a small drop in production in coming months, reflecting losses from possible hurricanes and declines related to the recent rig count slide. Data from Baker Hughes on Friday showed the gas-directed rig count fell last week by seven to 498, the 10th drop in 11 weeks and the lowest count since late July 1999. Dry gas drilling has become largely uneconomical at current prices, and a 47 percent drop in the gas rig count over the last nine months has fed expectations that producers were getting serious about slowing record output. But drillers have moved rigs to more-profitable shale oil and shale gas liquid plays that still produce plenty of associated gas that ends up in the market after processing. Baker Hughes also reported that horizontal rigs, the type used to extract oil or gas from shale, rose for the first time in four weeks, gaining four to 1,155. The horizontal count is down just 3 percent from the record high of 1,193 set in May. STORAGE ALSO AT RECORD Data last week from the EIA showed that domestic gas inventories for the week ended July 27 climbed to 3.217 trillion cubic feet, still a record high for that time of year. Despite the steady decline in the storage surplus to last year and the five-year average, total stocks stand at about 78 percent full, a level not normally reached until mid-September. Producing-region stocks are at 83 percent of estimated capacity. Concerns remain that excess storage gas could drive prices to new lows later this summer if inventories climb to levels that would test the government's 4.1-tcf estimate of capacity. EIA on Tuesday revised its estimate for end of October gas in storage to 3.954 tcf from a previous 4.002 tcf estimate. Injection estimates for Thursday's EIA report range from 23 bcf to 38 bcf, with most in the 30 bcf area. Stocks rose an adjusted 31 bcf during the same week last year, while the five-year average increase for that week is 45 bcf.