NEW YORK (Dow Jones)--Natural gas futures fluctuated Thursday ahead of government data expected to show a slightly larger-than-normal build in U.S. gas inventories.

Natural gas for October delivery on the New York Mercantile Exchange was trading 3.1 cents, or 1.14%, lower at $2.684 a million British thermal units after opening floor trading 3.6 cents lower at $2.679/MMBtu.

Mild weather, abundant supplies and the absence of hurricane activity continued to pressure prices lower Thursday.

"You really couldn't ask for a better combination for lower prices than all of that," said Mike Fitzpatrick, a broker with MF Global in New York.

The U.S. Energy Information Administration is expected to report that 65 billion cubic feet of gas were added to storage during week ended Aug. 28, according to the average prediction of 17 analysts and traders in a Dow Jones Newswires survey. The storage estimate falls short of last year's 92 bcf build in storage and is just above the five-year average injection of 64 bcf.

If the storage estimate is correct, inventories as of Aug. 28 will total 3.323 trillion cubic feet, 18% above the five-year average and 17% above last year's level. The EIA is scheduled to release its storage data Thursday at 10:30 a.m. EDT.

"The forecast [natural gas] storage change a little above average and forward thinkers know we'll have an even bigger build next week," wrote Drew Wozniak, an analyst with ICAP Energy in Louisville, Ky., in a note to clients Thursday. "The only thing the bulls can pray for is a suddenly emergent hurricane."

Commodity Weather Group, a Bethesda, Md. private forecaster, was predicting mostly normal temperatures across the eastern two-thirds of the U.S. from Sep. 3 to Sep. 12. The moderate temperatures were expected to curb the demand for natural gas for heating and cooling.

-By Christine Buurma, Dow Jones Newswires; 212-416-2143;