1539 ET - U.S. natural gas futures settle lower for a fourth consecutive session as the summer progresses with solid production and inventories weighing against weather-driven demand. Signals suggest the August contract will see a weak expiration tomorrow, Ritterbusch & Associates says in a note. "With the rollover to the September futures, the weather factor will begin to lose some bite at this later stage of the summer when the market will be forced to look ahead to the low-demand shoulder period." Short-term risk appears heavily tilted downward, the firm adds. Nymex gas for August delivery settles down 3.8% at $2.662/mmBtu and the September contract falls 3.1% to $2.701/mmBtu.