(New throughout, updates prices, market activity and comments) Jan 23 (Reuters) - U.S. natural gas futures jumped about 9% on Monday from a 19-month low in the prior session on Freeport LNG's request to begin the restart process for its liquefied natural gas (LNG) export plant in Texas and on forecasts for colder weather and higher heating demand over the next two weeks than previously expected. Freeport LNG, the second-largest U.S. LNG exporter, said it had completed repairs to its plant and asked U.S. regulators for permission to take early steps to restart the fire-idled facility. Freeport has said repeatedly that the plant is on track to restart in the second half of January, pending regulatory approvals. Analysts, however, said the plant would likely return in February or later due to the large amount of work needed to satisfy federal regulators. Freeport has already delayed the plant's planned restart date many times from October to November to December and most recently to January. Its return to service will boost demand for gas and prices will likely jump. The facility, which shut in a fire on June 8, 2022, can pull in around 2.1 billion cubic feet per day (bcfd) of gas and turn it into LNG when operating at full power. That is about 2% of U.S. daily production. Front-month gas futures for February delivery rose 27.3 cents, or 8.6%, to settle at $3.447 per million British thermal units (mmBtu). On Friday, the contract closed at its lowest since June 10, 2021. The front-month contract rose out of technically oversold territory for the first time in four days, on track for its biggest daily percentage gain since early November when it rose about 9.7%. But with prices down about 52% over the past five weeks, gas speculators last week boosted their net short futures and options positions on the New York Mercantile and Intercontinental Exchanges to the most since March 2020, according to the U.S. Commodity Futures Trading Commission's Commitments of Traders report. Shares outstanding in the U.S. Natural Gas Fund, an exchange-traded fund (ETF) designed to track the daily price movement of gas, hit 55.2 million on Friday, its fourth record high in a row, according to Refinitiv data. Purchases of UNG so far this year have already hit three of the top 10 biggest daily share purchases on record. With colder weather coming, Refinitiv forecast U.S. gas demand, including exports, would jump from 130.8 bcfd this week to 139.9 bcfd next week. Those forecasts were higher than Refinitiv's outlook on Friday. Traders said the biggest uncertainty in the market remains when the Freeport plant will return. Even though vessels have turned away from Freeport in recent weeks, several tankers were waiting in the Gulf of Mexico to pick up LNG from the plant, including Prism Diversity since around Oct. 28, Prism Courage since around Nov. 4 and Prism Agility since around Jan. 2. Corcovado LNG, which was waiting near Freeport, returned to just outside the plant over the weekend. In addition, other ships were sailing toward Freeport with both Prism Brilliance and Kmarin Diamond expected to arrive around Jan. 29. In other LNG news, the Cadiz Knutsen was expected to arrive at Constellation Energy Corp's Everett LNG terminal in Massachusetts over the next day or two with a fourth cargo of the super-cooled fuel from Trinidad this winter. Cadiz Knutsen also delivered LNG to Everett in November and December and early January. Week ended Week ended Year ago Five-year Jan 20 Jan 13 Jan 20 average (Forecast) (Actual) Jan 20 U.S. weekly natgas storage change (bcf): -78 +82 -217 -185 U.S. total natgas in storage (bcf): 2,742 2,820 2,622 2,601 U.S. total storage versus 5-year average +5.4% +1.2% Global Gas Benchmark Futures ($ per mmBtu) Current Day Prior Day This Month Prior Year Five Year Last Year Average Average 2022 (2018-2022) Henry Hub 3.48 3.17 4.26 6.54 3.60 Title Transfer Facility (TTF) 20.42 20.30 28.25 40.50 14.39 Japan Korea Marker (JKM) 22.82 22.95 28.53 34.11 14.31 Refinitiv Heating (HDD), Cooling (CDD) 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 490 459 508 430 436 U.S. GFS CDDs 3 3 2 4 3 U.S. GFS TDDs 493 462 510 434 439 Refinitiv U.S. Weekly GFS Supply and Demand Forecasts Prior Week Current Week Next Week This Week Five-Year Last Year Average For Month U.S. Supply (bcfd) U.S. Lower 48 Dry Production 98.9 99.0 99.2 93.2 88.8 U.S. Imports from Canada 8.4 8.4 9.3 10.2 9.4 U.S. LNG Imports 0.0 0.0 0.0 0.2 0.4 Total U.S. Supply 107.3 107.4 108.5 103.6 98.6 U.S. Demand (bcfd) U.S. Exports to Canada 2.8 2.7 2.7 2.3 2.8 U.S. Exports to Mexico 5.3 5.2 5.2 5.9 5.3 U.S. LNG Exports 12.4 12.5 12.0 12.9 7.2 U.S. Commercial 14.8 16.5 19.3 19.8 17.1 U.S. Residential 24.5 28.0 32.8 33.9 29.8 U.S. Power Plant 29.5 32.4 33.1 30.9 28.5 U.S. Industrial 24.6 25.6 26.6 26.2 25.6 U.S. Plant Fuel 4.9 4.9 4.9 4.9 4.9 U.S. Pipe Distribution 2.7 2.7 3.2 2.7 2.4 U.S. Vehicle Fuel 0.1 0.1 0.1 0.1 0.1 Total U.S. Consumption 101.1 110.5 120.1 118.5 108.4 Total U.S. Demand 121.6 130.8 139.9 139.6 123.7 U.S. weekly power generation percent by fuel - EIA Week ended Week ended Week ended Week ended Week ended Jan 27 Jan 20 Jan 13 Jan 6 Dec 30 Wind 9 13 11 12 11 Solar 2 2 2 2 2 Hydro 7 7 7 7 6 Other 2 2 2 2 2 Petroleum 0 0 0 0 0 Natural Gas 39 36 38 36 35 Coal 19 18 19 18 23 Nuclear 22 21 21 23 19 SNL U.S. Natural Gas Next-Day Prices ($ per mmBtu) Hub Current Day Prior Day Henry Hub 3.15 32.91 Transco Z6 New York 3.30 2.95 PG&E Citygate 14.93 15.07 Eastern Gas (old Dominion South) 2.66 2.44 Chicago Citygate 3.06 2.95 Algonquin Citygate 3.89 5.20 SoCal Citygate 14.76 17.03 Waha Hub 0.51 1.89 AECO 2.80 2.78 SNL U.S. Power Next-Day Prices ($ per megawatt-hour) Hub Current Day Prior Day New England 39.75 49.25 PJM West 38.50 42.00 Ercot North 21.50 18.00 Mid C 135.00 169.00 Palo Verde 100.00 125.25 SP-5 125.00 145.00 (Reporting by Scott DiSavino; Editing by Emelia Sithole-Matarise and David Gregorio)