NEW YORK, June 27 (Reuters) - U.S. natural gas futures lost ground early, with traders pulling back ahead of what is expected to be another bearish weekly inventory report due out later Thursday morning. Traders and analysts polled by Reuters expect to see an increase of 88 billion cubic feet in gas inventories when the U.S. Energy Inventory builds have exceeded the five-year average for the last three weeks and prompted some analysts to raise estimates for peak storage this year. On average, analysts are expecting stocks to top out this year at 3.767 trillion cubic feet, according to a Reuters poll released on Wednesday. If the forecast holds, it would be the first time in five years that gas inventories do not start winter at a record high. At 9:05 a.m. EDT (1305 GMT), front-month gas futures on the New York Mercantile Exchange were down 2.6 cents at $3.711 per million British thermal units after trading between $3.70 and $3.757. The front contract posted a 3-1/2-month low of $3.635 on Wednesday. Heat remains focused in the West for the next two weeks, but temperatures were also expected to trend warmer for the Northeast and northern tier states during the period, according to private forecaster MDA Weather Services. Readings in the Midwest and Southeast were expect to average below normal. Many traders remain skeptical of the upside without a sustained, broad-based heat wave, particularly with inventories comfortable and gas production still at or near a record high.