By Scott DiSavino

June 28 (Reuters) -U.S. natural gas futures climbed about 2% on Friday on forecasts for higher demand over the next two weeks than previously expected as power generators burn more gas to keep air conditioners humming during a brutal heat wave.

That price increase came even as producers boost output and the amount of gas in storage remains well above normal levels for this time of year.

Analysts forecast there was still about 19% more gas in storage than usual for this time of year even though output reductions earlier in the year kept weekly injections below normal over the past seven weeks. EIA/GAS] NGAS/POLL

Front-month gas futures NGc1 for August delivery on the New York Mercantile Exchange rose 3.9 cents, or 1.5%, to $2.724 per million British thermal units (mmBtu) at 9:09 a.m. EDT (1309 GMT).

For the week, prices were down about 1% after falling 6% last week and 1% two weeks ago.

For the month, prices were up about 4% after soaring about 30% in May and gaining 13% in April.

For the quarter, prices were up about 52% after dropping 30% in the first quarter.

In Texas, the Electric Reliability Council of Texas (ERCOT), the power grid operator for most of the state, said peak demand came close but did not break the record for the month of June on Thursday as had been expected. ERCOT, however, projects that demand will break the June record on Friday as homes and businesses crank up their air conditioners to escape the heat blanketing the state.

In the spot market, meanwhile, next-day gas prices at the Waha hub NG-WAH-WTX-SNL plunged 604% to a negative $2.78 per mmBtu, the lowest since mid April, as pipeline constraints trap gas in the Permian Shale. That is the second time gas prices fell into negative territory during a brutal heat wave this week and the 19th time so far this year.

SUPPLY AND DEMAND

Financial firm LSEG said gas output in the Lower 48 U.S. states rose to an average of 98.6 billion cubic feet per day (bcfd) so far in June, up from a 25-month low of 98.1 bcfd in May. That compares with a monthly record high of 105.5 bcfd in December 2023.

Meteorologists projected weather across the Lower 48 states would remain hotter than normal through at least July 13.

LSEG forecast average gas demand in the Lower 48, including exports, will slide from 103.2 bcfd this week to 100.8 bcfd with less heat and the July 4th holiday next week before soaring to 106.8 bcfd in two weeks when the weather is expected to turn extremely hot. The forecast for this week and next were higher than LSEG's outlook on Thursday.

Gas flows to the seven big U.S. LNG export plants eased to 12.8 bcfd so far in June, down from 12.9 bcfd in May and a monthly record high of 14.7 bcfd in December 2023.

That decline was due to plant and pipeline maintenance at several facilities, including Freeport LNG and Cheniere Energy's LNG.N Corpus Christi in Texas and Cameron LNG, Cheniere's Sabine Pass and Venture Global's Calcasieu Pass in Louisiana.

Reporting by Scott DiSavino; Editing by Anil D'Silva

For gas data on LSEG's Eikon type ENERGY in the search bar and then go to the GAS drop down and the NORTH AMERICA drop down.

For Interactive Map, type 'Interactive Map' in the box at upper left of the Eikon terminal

For graphics on Baker Hughes rig counts, see: http://graphics.thomsonreuters.com/15/rigcount/index.html

For next-day SNL U.S. gas prices, see: 0#SNL-NG

For next-day SNL U.S. power prices, see: 0#SNL-PWR

For U.S. natgas price and storage polls, see: NGAS/POLL

For U.S. nuclear power outages, see: NUKE/

For U.S. Northwest hydro power report, see: NWRFC

For U.S./Canada natural gas rig count vs Henry Hub futures price, see: http://tmsnrt.rs/2eT9k44

For the U.S. natural gas speed guide, see: USGAS

For the U.S. power speed guide, see: USPOWER

To determine CFTC managed money net position add (NYMEX Henry Hub options and futures combined 3023651MNET) plus (ICE Henry Hub options and futures combined 3023391MNET divided by four) plus (NYMEX Henry Hub swaps options and futures combined 303565BMNET divided by four) plus (NYMEX Henry Hub penultimate gas swaps 303565CMNET divided by four)

NYMEX Henry Hub options and futures combined 0#3CFTC023651

NYMEX Henry Hub futures only 0#1CFTC023651

ICE Henry Hub options and futures combined 0#3CFTC023391

NYMEX Henry Hub swaps options and futures combined 0#3CFTC03565B

NYMEX Henry Hub Penultimate gas swaps 0#3CFTC03565C