The possibility of another warm winter this year caused natural gas traders to drop futures for the first half of 2018, driving the full calendar strip to its lowest level on record, according to analysts and Reuters data going back to 2015.

Those declines boosted the premium of calendar 2019 over 2018 to its highest since April 2016.

Until this week, calendar 2018 was trading at a premium over 2019 and did so for more than 15 months as the market bet rising U.S. LNG exports and cold weather this winter would inflate prices next year.

Traders, however, said the latest winter forecasts for seasonal weather through the end of the year disappointed market bulls.

“A significant shift in the short-term 1-2 week temperature views was enough to ignite another influx of fund capital back into the short side,” Jim Ritterbusch, president of Chicago-based energy advisory firm Ritterbusch & Associates, said in a report.

Last week, U.S. gas speculators cut their net long positions to the least since August 2016 on expectations supplies will be adequate this winter with storage near normal levels, output at record highs and warmer than seasonal winter forecasts.

The winters of 2015-2016 and 2016-2017 were among the warmest on record.

Production in the lower 48 U.S. states averaged an all-time high of 76.2 billion cubic feet per day (Bcf/d) over the past 30 days, according to Reuters data. Daily output peaked at the end of November at 76.8 Bcf/d and has remained near that level since.

The U.S. is expected to become a net gas exporter on an annual basis in 2017 for the first time in 60 years, due in part to sharp growth in LNG sales abroad.

U.S. exports will rise from an annual average of 6.4 Bcf/d in 2016 to 8.7 Bcf/d in 2017 and 10.3 Bcf/d in 2018, according to federal energy projections in December.

That rapid export growth was due to the ramp up of four 0.7-Bcf/d liquefaction trains at Cheniere Energy Inc.’s (NYSE MKTS: LNG) Sabine Pass LNG export facility in Louisiana since the first train entered service in February 2016.

By the end of the year, another LNG export facility is expected to join Sabine Pass when Dominion Energy Inc.’s (NYSE: D) 0.75-bcfd Cove Point terminal in Maryland enters service.