By Scott DiSavino

March 31 (Reuters) - U.S. natural gas futures climbed about 5% to a two-week high on Monday on record flows to liquefied natural gas export plants and forecasts for cooler weather and more demand next week than previously expected.

Gas futures NGc1 for May delivery on the New York Mercantile Exchange were up 18.3 cents, or 4.5%, at $4.248 per million British thermal units (mmBtu) at 8:41 a.m. EDT (1241 GMT), putting the contract on track for its highest close since March 11.

That also put the contract up about 11% for the month and 17% for the quarter.

The increase in the May front-month, meanwhile, cut the premium of futures for June over May NGK25-M25 to their lowest since December 2023.

Energy traders said mild weather and low demand in March likely allowed utilities to add gas to storage in March for the first time since 2012 and only the second time in history.

Gas stockpiles, however, were still about 5% below normal levels for this time of year after extremely cold weather in January and February forced energy firms to pull large amounts of gas out of storage, including record amounts in January. EIA/GAS NGAS/POLL

In the U.S. West, mild weather and ample hydropower cut spot power prices at the Mid-Columbia Hub W-MIDCP-IDX in Oregon to their lowest since May 2023.

SUPPLY AND DEMAND

Financial firm LSEG said average gas output in the Lower 48 U.S. states had risen to 105.9 billion cubic feet per day (bcfd) so far in March, up from a record 105.1 bcfd in February.

Meteorologists projected temperatures in the Lower 48 states would remain mostly near normal through April 15.

LSEG forecast average gas demand in the Lower 48, including exports, will slide from 102.6 bcfd this week to 106.7 bcfd next week. The forecasts for next week was higher than LSEG's outlook on Friday.

The amount of gas flowing to the eight big operating U.S. LNG export plants has risen to an average of 15.8 bcfd so far in March, up from a record 15.6 bcfd in February, as new units at Venture Global's VG.N 3.2-bcfd Plaquemines LNG plant under construction in Louisiana entered service.

The U.S. became the world's biggest LNG supplier in 2023, surpassing Australia and Qatar, as surging global prices fed demand for more exports due in part to supply disruptions and sanctions linked to Russia's 2022 invasion of Ukraine.

Gas traded around $13 per mmBtu at both the Dutch Title Transfer Facility (TTF) TRNLTTFMc1 benchmark in Europe and the Japan Korea Marker (JKM) JKMc1 benchmark in Asia. NG/EU

(Reporting by Scott DiSavino; Editing by Jan Harvey)

((scott.disavino@thomsonreuters.com; +1 332 219 1922; Reuters Messaging: scott.disavino.thomsonreuters.com@reuters.net))

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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