(Updates for market close)

Dec 23 (Reuters) - U.S. natural gas futures edged down on Monday from a near 23-month high in volatile trading, as short-term warmer weather forecasts countered support from a rise in the amount of gas flowing to liquefied natural gas $(LNG)$ export plants and long-term cooler forecasts.

Front-month gas futures for January delivery on the New York Mercantile Exchange settled down 9.2 cents, or 2.5%, to $3.66 per million British thermal units (mmBtu) at 02:43 p.m. EST (1943 GMT).

"We saw a big spike up in prices on Sunday night, but then we're giving back those gains. The bearish arguments are that it's not going to be that cold and there's still plenty of supply. The bullish arguments are if the cold does settle in, prices will stay strong. So we're seeing kind of a volatile situation," said Phil Flynn, an analyst at Price Futures Group.

"It really is a battle between short-term warmer forecast and longer-term forecasts for cold, and that's why we're seeing some extreme volatility," Flynn said.

Financial firm LSEG estimated 370 heating degree days over the next two weeks, lower than the 10-year normal of 424 HDDs and the 30-year normal of 431 HDDs.

The amount of gas flowing to the eight big U.S. LNG export plants rose to an average of 14.8 bcfd so far in December from 13.6 bcfd in November. That compares with a monthly record high of 14.7 bcfd in December 2023.

LSEG said average gas output in the Lower 48 U.S. states rose to 103 billion cubic feet per day (bcfd) so far in December from 101.5 bcfd in November. That compares with a record 105.3 bcfd in December 2023.

Financial firm LSEG forecast average gas demand in the Lower 48, including exports, dropping from 132.8 bcfd this week to 121.3 bcfd next week.

"Going forward into the new year, the extended temperature forecasts suggest a lot of zig zags between colder and milder temperature trends, but it will likely require an unusually cold January to flip the long-standing storage surplus to a deficit capable of advancing this market much further," energy advisory firm Ritterbusch and Associates said in a note.

Dutch and British wholesale gas prices rose slightly, as they traded in a narrow range, caught between low wind speed and uncertainty over Russian gas flows to Europe when the Ukraine gas transit deal expires at year-end.

Week ended Week ended Year ago Five-year

Dec 20 Dec 13 Dec 20 average

Forecast Actual Dec 20

U.S. weekly natgas storage change (bcf):

-97 -125 -87 -127

U.S. total natgas in storage (bcf):

3,525 3,622 3,515 3,363

U.S. total storage versus 5-year average

4.8% 3.8%

Global Gas Benchmark Futures ($ per mmBtu) Current Day Prior Day This Month Prior Year Five-Year

Last Year Average Average

2023 (2018-2022)

Henry Hub 2.54 2.66 3.60

3.71 3.67

Title Transfer Facility (TTF) 11.55 13.04 14.39

13.82 13.27

Japan Korea Marker (JKM) 14.03 14.39 14.31

13.46

LSEG Heating $(HDD.UK)$, Cooling $(CDD.AU)$ and Total (TDD) Degree Days

Two-Week Total Forecast Current Day Prior Day Prior Year 10-Year 30-Year

Norm Norm

U.S. GFS HDDs

370 352 365 424 431

U.S. GFS CDDs

2 3 1 4 3

U.S. GFS TDDs

372 355 366 428 434

LSEG U.S. Weekly GFS Supply and Demand Forecasts

Prior Week Current Next Week This Week Five-Year

Week Last Year (2019-2023)

Average For

Month

U.S. Supply (bcfd)

U.S. Lower 48 Dry Production 105.6 97.8

103.4 102.7 102.2

U.S. Imports from Canada N/A 8.7

9.5 10.0 9.6

U.S. LNG Imports 0.0 0.2

0.0 0.1 0.0

Total U.S. Supply N/A 106.7

112.9 112.8 111.8

U.S. Demand (bcfd)

U.S. Exports to Canada N/A 3.4

3.5 3.5 3.5

U.S. Exports to Mexico N/A 5.4

5.8 5.8 5.7

U.S. LNG Exports 14.7 10.8

13.9 14.4 14.6

U.S. Commercial 13.8 14.3

14.4 16.5 13.7

U.S. Residential 22.0 23.4

23.4 27.5 22.3

U.S. Power Plant 35.1 30.3

30.9 31.7 29.5

U.S. Industrial 24.7 25.1

24.7 25.3 24.4

U.S. Plant Fuel 5.1 5.2

5.1 5.1 5.0

U.S. Pipe Distribution 2.8 3.7

2.7 2.9 2.6

U.S. Vehicle Fuel 0.1 0.1

0.1 0.1 0.1

Total U.S. Consumption 103.6 102.1

101.5 109.1 97.6

Total U.S. Demand N/A 121.7

124.7 132.8 121.3

N/A is Not Available

U.S. Northwest River Forecast Center (NWRFC) at The Dalles Dam 2025 2025 2024 2003 2022

Current Day Prior Day % of Normal % of Normal % of Normal

% of Normal % of Normal Actual Actual Actual

Forecast Forecast

Apr-Sep 74 83 107

94 92

Jan-Jul 76 77 102

91 90

Oct-Sep 77 76 103

93 91

U.S. weekly power generation percent by fuel - EIA

Week ended Week ended 2023 2022 2021

Dec 27 Dec 20

Wind 10 11 10

11 13

Solar 4 3 3

4 3

Hydro 6 6 7

6 6

Other 2 2 2

1 1

Petroleum 0 0 0

0 0

Natural Gas 41 38 37

39 39

Coal 17 21 23

19 17

Nuclear 19 19 20

21 21

SNL U.S. Natural Gas Next-Day Prices ($ per mmBtu)

Hub Current Day Prior Day

Henry Hub

3.10 3.15

Transco Z6 New York

8.22 3.31

PG&E Citygate

3.45 3.45

Eastern Gas (old Dominion South)

2.79 2.81

Chicago Citygate

2.86 2.92

Algonquin Citygate

15.69 10.63

SoCal Citygate

3.46 3.61

Waha Hub

2.39 2.79

AECO

1.68 1.20

SNL U.S. Power Next-Day Prices ($ per megawatt-hour)

Hub Current Day Prior Day

New England 53.50

PJM West 35.50

Ercot North 27.88

Mid C 36.83

Palo Verde 45.00

SP-15 45.25

(Reporting by Anjana Anil and Anmol Choubey in Bengaluru; Editing by Mark Porter)

((Anjana.Anil@thomsonreuters.com;))

((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: For next-day SNL U.S. gas prices, see: For next-day SNL U.S. power prices, see: For U.S. natgas price and storage polls, see: For U.S. nuclear power outages, see: For U.S. Northwest hydro power report, see: For U.S./Canada natural gas rig count vs Henry Hub futures price, see: For the U.S. natural gas speed guide, see: For the U.S. power speed guide, see: To determine CFTC managed money net position add (NYMEX Henry Hub options and futures combined ) plus (ICE Henry Hub options and futures combined divided by four) plus (NYMEX Henry Hub swaps options and futures combined divided by four) plus (NYMEX Henry Hub penultimate gas swaps divided by four) NYMEX Henry Hub options and futures combined NYMEX Henry Hub futures only ICE Henry Hub options and futures combined NYMEX Henry Hub swaps options and futures combined NYMEX Henry Hub Penultimate gas swaps ))