Natural gas prices sank to a two-month low Friday as the approaching autumn threatens demand. Futures for September delivery settled down 7.9 cents, or 2.9%, to $2.676 a million British thermal units on the New York Mercantile Exchange. It is the lowest settlement since June 5 and breaks gas out slightly from a 25-cent range it had settled within every session since then. Gas lost 4.5% for the week, its largest weekly loss since late May. It snapped a two-week winning streak. Summer prices are closely tied to heat because consumption usually rises as people turn on their air-conditioning units and ramp up demand for gas-powered electricity. Friday’s weather forecasts are little changed, but the peak of the summer is starting to pass. Traders are looking ahead to the fall, when consumers typically use less natural gas because weather is too mild to cause heating or cooling demand, analysts […]