May natural gas is set to open flat Thursday morning at $2.61 as traders focus on what may be a surprise inventory report but nonetheless showing storage increases well above historical norms. Overnight oil markets fell.

Analysts see Wednesday’s stout 8-cent gain being derived from a change in the weather outlook. “With the transition into more spring-like weather, the daily forecasts had taken a back seat to the general pessimistic sentiment on supply, with prices falling sharply last week. Now, however, colder weather ahead this month will likely limit the potential stock build, which in turn is spurring a short-term recovery in natural gas prices,” said Teri Viswanath, director of natural gas trading strategy at BNP Paribas, in a Wednesday morning note to clients.

Going forward, however, Viswanath still sees April storage builds outpacing those of a year ago. “For the last two weeks, daily storage injections have outpaced year-ago levels by more than 3 Bcf/d. Colder changes in the weather forecast, with overnight temperatures dipping back below freezing in the Midwest next week, will closer align supply-demand balances with year-ago levels. Consequently, we expect the industry to outpace last year’s daily injection by an average of just 1.5 Bcf/d this month, with the net build in working gas in storage amounting to 254 Bcf compared to last year’s 209 Bcf.”

Thursday’s 10:30 a.m. EDT Energy Information Administration inventory report for the week ending April 10 may shed some light on whether that 254 Bcf April increase is in sight. Viswanath predicts an increase of 57 Bcf, right in the middle of the pack. Last year 22 Bcf was injected, and the five-year pace stands at 35 Bcf. IAF Advisors of Houston is looking for a build of 62 Bcf, and ICAP Energy figures on a 60 Bcf increase. A Reuters poll of 24 traders and analysts showed a sample mean of 53 Bcf with a range of 37 to 66 Bcf.

The best minds in the business may be looking for 60 Bcf, but John Sodergreen, publisher of Energy Metro Desk hints that there may be a surprise. “[A]ll the usual indicators point to a surprise. The spread between the three categories we track is 4.6 Bcf, well above the 3 Bcf that ordinarily points to a surprise. The range was over 20 Bcf so, high. We note that the past three reports EIA has come in with a number higher than market expectations — average delta is around 5 Bcf. We’ve not seen EIA ever come in more than three times in a row higher than the market, but we think this week might be the exception to that particular statistic.”

For the week ending April 17, Reuters’ preliminary figures show a 71 Bcf average with a range of 68 to 91 Bcf. That would compare to year ago builds of 45 Bcf and a five-year norm of 46 Bcf.

In overnight Globex trading May crude oil fell $1.08 to $55.31/bbl and May RBOB gasoline skidded 4 cents to $1.9008/gal.