U.S. natural gas futures rose about 3% to a one-week high on Wednesday on a drop in daily output this week and forecasts for hotter weather through early July than previously expected.

On its first day as the front month, gas futures for August delivery on the New York Mercantile Exchange (NYMEX) rose 22.4 cents, or 3.4%, to $6.794 per million British thermal units (mmBtu) at 7:55 a.m. EDT (1155 GMT), putting the contract on track for its highest close since July 22.

With the U.S. Federal Reserve expected to keep raising interest rates, open interest in NYMEX futures fell on Tuesday to its lowest since July 2016 for a second day in a row as investors continued to cut back on risky assets.

So far this year, U.S. gas futures are up about 82% as much higher prices in Europe and Asia keep demand for U.S. liquefied natural gas (LNG) exports strong, especially since Russia's Feb. 24 invasion of Ukraine stoked fears Moscow might cut gas supplies to Europe.

Gas was trading around $43 per mmBtu in Europe and $37 in Asia. U.S. futures lag far behind global prices because the United States is the world's top producer, with all the gas it needs for domestic use, while capacity constraints inhibit additional LNG exports.

Data provider Refinitiv said average gas output in the U.S. Lower 48 states slid to 95.1 billion cubic feet per day (bcfd) so far in June from 95.2 bcfd in May. That compares with a monthly record of 96.1 bcfd in December 2021.

On a daily basis, output was on track to drop 2.1 bcfd over the past four days to a preliminary two-week low of 94.0 bcfd on Wednesday after hitting a six-month high of 96.1 bcfd on Saturday.

Preliminary data, however, is often revised higher later in the day. With hotter weather coming, Refinitiv projected average U.S. gas demand including exports would rise from 94.2 bcfd this week to 95.5 bcfd next week.

The forecast for next week was lower than Refinitiv's outlook on Tuesday. The amount of gas flowing to U.S. LNG export plants dropped from an average of 12.5 bcfd in May to 11.2 bcfd so far in June due to the June 8 outage at Freeport LNG's plant in Texas, which is expected to last about three months. That compares with a monthly record of 12.9 bcfd in March.

The seven big U.S. export plants can turn about 13.6 bcfd of gas into LNG. Freeport, the second-biggest U.S. LNG export plant, was consuming about 2 bcfd of gas before it shut, so a 90-day outage would leave around 180 billion cubic feet (bcf) of gas available to the U.S. market.

Analysts said that should allow U.S. utilities to quickly rebuild low gas stockpiles ahead of next winter, but cuts the amount of U.S. gas available to the rest of the world. That is a problem for Europe where most U.S. LNG has gone as countries there wean themselves off Russian energy since Moscow's invasion of Ukraine.

Over the past two weeks, Russia has exported just 3.7 bcfd of gas on the three main lines into Germany - Nord Stream 1 (Russia-Germany), Yamal (Russia-Belarus-Poland-Germany) and the Russia-Ukraine-Slovakia-Czech Republic-Germany route. That is down from around 6.5 bcfd in mid June and an average of 11.6 bcfd in June 2021.

Gas stockpiles in Northwest Europe - Belgium, France, Germany and the Netherlands - were about 9% below the five-year (2017-2021) average for this time of year, and down from 39% below the five-year norm in mid-March, according to Refinitiv.

Storage was currently about 52% of full capacity. That is healthier than U.S. inventories, which were around 13% below their five-year norm. 

(Reporting by Scott DiSavino; editing by David Evans)