NEW YORK, Sept 27 (Reuters) - U.S. natural gas futures lost ground on Friday, pressured ahead of the weekend by moderate weather forecasts for much of the nation over the next two weeks that should slow overall demand. The front-month contract, which eked out a fractional gain last week for its fifth rise in the previous six weeks, is down 5.1 percent so far this week despite slim gains in the previous two sessions. A milder turn in the weather and no serious storm threats to U.S. Gulf gas production have kept buyers relaxed. "Temperature forecasts continue to be unsupportive for natural gas prices as benign conditions look set to limit both air conditioning demand and heating load," Addison Armstrong, director of market research at Tradition Energy in Stamford, Connecticut, said in a report. At 8:55 a.m. EDT (1255 GMT), front-month gas futures on the New York Mercantile Exchange were down 3.1 cents, or 0.9 percent, at $3.536 per million British thermal units, after trading between $3.527 and $3.588. The front contract on Thursday slid to a five-week low of $3.402 after a bearish weekly inventory report. While the market is still slightly oversold and could stage a technical bounce, many traders remain skeptical of any upside with inventories comfortable, production flowing at a record pace and no cold weather on the horizon to kick up heating load. The National Weather Service six- to 10-day outlook calls for above normal temperatures for the eastern half of the nation. Traders noted that at this time of year readings several degrees above the norm were not likely to stir much air conditioning demand. Traders viewed Thursday's 87 billion cubic feet weekly inventory build as bearish, noting it came in above the highest estimate of 83 bcf in the Reuters weekly storage poll. It also came in above the 79 bcf gain seen during the same week last year and the five-year average increase for that week of 75 bcf. U.S. Energy Information Administration data showed total domestic gas inventories stood at 3.386 trillion cubic feet, about 5 percent below last year's record highs at that time, but nearly 1 percent above the five-year average. Early estimates for next week's storage report range from 85 to 92 bcf. Stocks gained 77 bcf during the same year-ago week, while the five-year average rise for that week is 82 bcf. Traders were waiting for the next Baker Hughes gas-directed drilling rig report on Friday. Despite last week's rig decline, the count has risen in eight of the last 13 weeks, stirring talk that new investment in pipelines and processing plants was allowing producers to pump more gas into an already well-supplied market. The EIA still expects U.S. gas production in 2013 to hit a record high for the third straight year. Nuclear plant outages on Friday totaled 9,358 megawatts, or about 10 percent of U.S. capacity. That was up from Thursday's total of 8,484 MW but below the 16,587 MW out one year ago and the five-year average outage rate of 12,431 MW. Despite a rise in tropical activity this month, traders noted there were no threats as yet to Gulf of Mexico gas output.