NEW YORK: US natural gas futures fell to a fresh one-week low on Thursday on forecasts for slightly less hot weather and lower air conditioning demand this week than previously expected.

That decline also came after federal data showed last week's storage build was bigger than usual due to mild weather and a decline in exports.

The US Energy Information Administration (EIA) said utilities added 49 billion cubic feet (bcf) of gas into storage during the week ended Aug. 6.

That matched the build analysts forecast in a Reuters poll and compares with an increase of 55 bcf in the same week last year and a five-year (2016-2020) average increase of 42 bcf.

Last week's injection boosted stockpiles to 2.776 trillion cubic feet (tcf), or 6.0% below the five-year average of 2.954 tcf for this time of year.

Front-month gas futures fell 5.9 cents, or 1.5%, to $4.000 per million British thermal units (mmBtu) at 10:38 a.m. EDT (1438 GMT), putting the contract on track for its lowest close since Aug. 2.

In the power market, the Electric Reliability Council of Texas (ERCOT), grid operator for most of the state, projected hot weather Thursday would push peak demand over the current high for the year of 72,856 megawatts (MW) set on July 26. That, however, is below the grid's all-time high of 74,820 MW set in August 2019.

In the US Pacific Northwest, power prices at the Mid Columbia hub in Washington state slipped to $123 per megawatt hour for Thursday from $174 for Wednesday. High temperatures in Portland, Oregon, were expected to top 100 degrees Fahrenheit (38 Celsius) on Aug. 11-13. The city's normal high is 80 F at this time of year.

In the Atlantic basin, meanwhile, Tropical Depression Fred was expected to strengthen into a storm as it marches toward the South Florida area on Saturday.

Data provider Refinitiv said gas output in the US Lower 48 states rose to an average of 92.0 billion cubic feet per day (bcfd) so far in August from 91.6 bcfd in July. That compares with an all-time high of 95.4 bcfd in November 2019.