September natural gas expired at a new contract low yesterday, weighed down by reduced Northeast demand for natural gas. Estimates late Monday indicated that roughly 5.5 million people were without power in the Northeast, which has reduced natural gas demand in the region by more than 2.5 bcf per day. Meanwhile, some traders viewed the lower pricing as a factor that might encourage more storage buying in the near term. The National Hurricane Center has upgraded the depression off the Cape Verde islands to Tropical Storm Katia.