Adds latest prices

By Scott DiSavino

Sept 24 (Reuters) -U.S. natural gas futures slid about 2%on Tuesday on forecasts for less demand over the next two weeks than previously expected.

Another factor weighing on gas prices was the latest forecasts for Tropical Storm Helene to miss most of the producing regions in the western and central Gulf of Mexico as it strengthens into a hurricane on Wednesday and hit the Florida Panhandle late Thursday.

Over the past few days, severaloil companies paused some production ahead of Helene.But some firms, likeShell SHEL.L, started restoring oil and gas production as the forecasted storm movements shifted away from their offshore platforms.

Front-month gas futures NGc1 for October delivery on the New York Mercantile Exchange fell 6.2 cents, or 2.4%, to settle at $2.551 per million British thermal units (mmBtu).On Monday, the contract closed at its highest level since June 27.

With front-month gas prices up about 27% over the past five weeks, the premium of futures for November over October NGV24-X24 fell to just 24cents per mmBtu, the lowest since September 2022. October is the current front-month.

Analysts have said gas prices should trade at lower levels during the April-October summer cooling season than the November-March winter heating season since U.S. demand for gas peaks during the winter.

SUPPLY AND DEMAND

LSEG said gas output in the Lower 48 U.S. states slid to an average of 102.0 billion cubic feet per day (bcfd) so far in September, down from 103.2 bcfd in August.

But on a daily basis, output was on track to drop by around 3.2 bcfd over the past four days to a preliminary four-month low of 99.6 bcfd. Analysts, however, noted that preliminary data was often revised later in the day.

Analysts said the recent output reductions were partly due to producers curtailing Gulf of Mexico oil and gas production ahead of Helene and lower flows on aNatural Gas Pipeline Co (NGPL) pipe in Texas after a force majeure event at a compressor.

With milder autumn weather coming, LSEG forecast average gas demand in the Lower 48 states, including exports, will slide from 98.5 bcfd this week to 96.4 bcfd next week. Those forecasts were lower than LSEG's outlook on Monday.

Gas flows to the seven big U.S. LNG export plants have eased to an average of 12.8 bcfd so far in September, down from 12.9 bcfd in August. That compares with a monthly record high of 14.7 bcfd in December 2023.

That reduction was due mostly to the planned Sept. 20 shutdown of Berkshire Hathaway Energy's 0.8-bcfd Cove Point LNG export plant in Maryland for around three weeks of annual maintenance.

In other LNG news, a tanker docked for the past month at Venture Global LNG's Plaquemines export plant under construction in Louisiana left by Tuesday morning, according to data provider LSEG.

Energy analysts said that was likely a sign Plaquemines was getting closer to producing and exporting its own LNG.

Reporting by Scott DiSavino; Editing by Paul Simao and David Gregorio

For gas data on the LSEG terminal 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 LSEG 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

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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