By Scott DiSavino

July 9 (Reuters) -U.S. natural gas futures climbed about 3% on Tuesday on forecasts for the brutal heat wave blanketing much of the country to remain in place through at least late July, forcing power generators to burn lots of gas to produce electricity to keep air conditioners humming.

The price increase came despite forecasts for less demand next week than previously expected, recent increases in output and a drop in the amount of gas flowing to liquefied natural gas (LNG) export plants after Freeport LNG in Texas shut ahead of Hurricane Beryl.

Oil and gas companies in Texas were restarting operations after Hurricane Beryl lashed the state with 80-mile per hour (129-km per hour) winds, damaging property and leaving millions of people without power.

Hurricane Beryl lashed Texas with strong winds and heavy rains as it churned inland, forcing the closure of oil ports, cancellation of hundreds of flights and leaving over 2.7 million homes and businesses without power. About 2.3 million homes and businesses in Texas were still without power on Tuesday, down from more than 2.7 million on Monday.

Front-month gas futures NGc1 for August delivery on the New York Mercantile Exchange rose 6.2 cents, or 2.6%, to $2.428 per million British thermal units (mmBtu) at 9:00 a.m. EDT (1300 GMT).

But with gas prices down about 21% over the past four weeks, speculators last week cut their net long futures and options positions on the New York Mercantile and Intercontinental Exchanges for a second week in a row to their lowest since early June, according to the U.S. Commodity Futures Trading Commission's Commitments of Traders report.

SUPPLY AND DEMAND

Financial firm LSEG said gas output in the Lower 48 U.S. states rose to an average of 102.4 billion cubic feet per day (bcfd) so far in July.

That was up from an average of 100.2 bcfd in June and a 17-month low of 99.5 bcfd in May when many producers reduced drilling activities after prices fell to 3-1/2-year lows in February and March. U.S. output hit a monthly record high of 105.5 bcfd in December 2023.

Higher prices in April, May and June prompted some producers, including EQT EQT.N and Chesapeake Energy CHK.O, to start pulling more gas out of the ground. On a daily basis, output hit a 17-week high of 103.0 bcfd on Sunday.

EQT is the nation's biggest gas producer, and Chesapeake is on track to become the biggest after its planned merger with Southwestern Energy SWN.N.

Meteorologists projected weather across the Lower 48 states would remain hotter than normal through at least July 24.

With hotter weather expected next week, LSEG forecast average gas demand in the Lower 48, including exports, will rise from 105.7 bcfd this week to 107.0 bcfd next week. The forecast for this week was lower than LSEG's outlook on Friday, while the forecast for next week was higher.

Gas flows to the seven big U.S. LNG export plants fell to 12.2 bcfd so far in July after Freeport LNG in Texas shut ahead of Hurricane Beryl on Sunday, down from 12.8 bcfd in June and a monthly record high of 14.7 bcfd in December 2023.

The U.S. became the world's biggest LNG supplier in 2023, ahead of recent leaders Australia and Qatar, as much higher global prices fed demand for more exports due in part to supply disruptions and sanctions linked to Russia's invasion of Ukraine.

With worries about Hurricane Beryl receding, gas prices fell to a seven-week low of around $10 per mmBtu at the Dutch Title Transfer Facility (TTF) benchmark in Europe TRNLTTFMc1 and a three-week low of $12 at the Japan Korea Marker (JKM) benchmark in Asia JKMc1. NG/EU

Reporting by Scott DiSavino, Editing by Louise Heavens

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