US working natural gas volumes in underground storage added 104 Bcf last week, flipping the deficit to the five-year average to a surplus for the first time in more than two years. Storage inventories increased to 3.519 Tcf for the week ended October 11, the US Energy Information Administration reported Thursday morning. The injection was less than an S&P Global Platts survey of analysts calling for a 108-Bcf addition. Survey responses ranged for an injection of 95 Bcf to 112 Bcf.

The build was more than the 82-Bcf injection reported during the corresponding week in 2018 as well as the five-year average addition of 81 Bcf, according to EIA data. As a result, stocks were 494 Bcf, or 16.3%, more than the year-ago level of 3.025 Tcf and 14 Bcf, or 0.4%, more than the five-year average of 3.505 Tcf.

The NYMEX Henry Hub November contract added 5 cents to $2.353/MMBtu following the announcement.

The NYMEX winter strip has once again moved toward a fairly bullish streak, although not to the same extent as was seen in mid-September, when its valuation rose above the $2.80 mark from $2.40 a few weeks earlier. This time, the contract strip has strengthened by about 10 cents over the last week, now trading at $2.52 for the season, up from $2.41 this time last week.

The summer build-up has come from strong production, exacerbated by recent declines in power burn demand, according to data by S&P Global Platts Analytics. Those factors are likely to keep injections strong through October, until residential and commercial demand ramps up in November.