Natural gas futures slid to a one-week low Tuesday as market participants braced for a drop-off in demand as temperatures moderate.

Natural gas for September delivery settled 9.2 cents, or 2.29%, lower, at $3.932 a million British thermal units on the New York Mercantile Exchange.

The benchmark contract touched a one-week low of $3.903/MMBtu during the session, the eighth of the last nine in which it has crossed below the psychologically important $4 floor.

With sweltering temperatures that have plagued many big power markets easing, "the natural gas market is on a scripted path to a third-quarter low," said Brian Habacivich, senior vice president of research with energy consultancy Fellon-McCord.

Since spring, prices have been buoyed by a deficit between the volume of gas in U.S. storage and the five-year average. That gap, which usually closes in spring and early summer when demand is light, was held by unusually hot weather that created demand for gas to generate electricity for air conditioning. The storage gap, which is currently 80 billion cubic feet, should quickly close without sweltering temperatures to burn up record production.

While hotter-than-normal temperatures should continue to plague Texas, the Midwest and Northeast should trend "toward the cooler side" over the next two weeks, said private forecasters MDA EarthSat.

"This cool air mass is not expected to be intense, only allowing seasonal to marginal below normal temperatures to reach these regions," the meteorologists said. "Meanwhile, a slightly stronger ridge in the Rockies could permit more much above normal readings for the interior West."

Without steamy weather to spur demand, traders will look to the tropics for potential supply disrupting storms.

So far this season only one named storm, Don, has passed over the northern Gulf's gas producing areas, with most others curling toward the North Atlantic.

The second half of hurricane season tends to be more active in the Gulf, though. The National Hurricane Center has said that a tropical wave in the eastern Caribbean Sea has a 20% chance of developing into a tropical cyclone.

But the mere threat of storm may not move the market like it once would have. With much of the country's natural gas now coming from onshore fields, the Gulf of Mexico now accounts for only 7.2% of domestic output, down from 16.5% in 2005, according to the Energy Information Administration.

"The market is not overly concerned about production threats," Habacivich said. "The market is saying show me a hurricane and I'll decide what to do with it."