Adds latest prices

By Scott DiSavino

Sept 27 (Reuters) -U.S. natural gas futures jumped about 5% to a 14-week high on Friday as Hurricane Helene battered the U.S. Southeast after causing Gulf of Mexico producers to cut output and knocking out power to millions of customers in Florida, Georgia and the Carolinas.

Energy traders noted that prices were also supported as the amount of gas flowing to Venture Global's Plaquemines LNG export plant in Louisiana was on track to match a high of around 35 million cubic feet per day that it hit in mid-August. That is still a very small amount of gas. The first phase of the Plaquemines project will have the capacity to turn about 1.8 billion cubic feet per day of gas into LNG.

Analysts have said the plant could start producing LNG in test mode over the next month or so. Officials at Venture Global were not immediately available for comment.

Another factor analysts have noted that has supported prices in recent weeks was that storage injections in July, August and so far in September were at record lows, according to federal energy data going back to 1997. That is because many producers cut output earlier this year after average spot monthly prices at the U.S. Henry Hub NG-W-HH-SNL benchmark in Louisiana fell to a 32-year low.

On its first day as the front-month, gas futures NGc1 for November delivery on the New York Mercantile Exchange rose 14.9 cents, or 5.4%, from where they traded on Thursday to settle at $2.902 per million British thermal units (mmBtu) on Friday, their highest close since June 18.

That, however, was up about 12% from where the less expensive October contract closed when it was still the front-month on Thursday.

That expiration-caused price increase pushed the front-month back into technically overbought territory for the third time this week after hitting that level on Monday and Wednesday.

For the week, the contract was up about 19%, putting it on track for a fifth week of gains for the first time since April 2022. During that time, the front-month has gained about 43%.

The U.S. National Hurricane Center forecast the remnants of Helene, now a tropical depression, would remain over Tennessee and Kentucky over the weekend.

There were currently about 4.6 million homes and businesses without power, mostly in Florida, Georgia and the Carolinas, from Helene. That is down from around 5.2 million affected by the storm as utilities in Florida, Georgia and South Carolina have been able to restore service to some customers since the storm slammed into the Florida Panhandle late Thursday.

Although storms are more likely to reduce gas prices and demand through power outages and shutting of liquefied natural gas export plants, analysts said this storm was on track to miss the LNG plants.

That means demand for gas from those LNG export plants should remain high at the same time that some Gulf Coast producers have cut output. The U.S. Bureau of Safety and Environmental Enforcement said that about 18%, or 0.3 bcfd, of gas production in the U.S. Gulf of Mexico was still shut-in for Helene.

More than 75% of U.S. gas production still comes from big inland shale basins like Appalachia in Pennsylvania, West Virginia and Ohio and the Permian in West Texas and eastern New Mexico, so most of the country's gas output should remain safe from the storm.

Reporting by Scott DiSavino; Editing by Jonathan Oatis and Daniel Wallis

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

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