** Shares of U.S. natural gas companies fall, tracking natgas futures NGA/
** U.S. natgas futures NGc1 down 2.2% at $4.21 per million British thermal units (mmBtu)
** Natural gas prices were weighed down by forecasts for warmer-than-normal weather and lower heating demand over the next two weeks than previously expected
** Natgas companies NextDecade NEXT.O down 2.6%, Energy Transfer ET.N falls 1.4% and Williams Companies WMB.N down 1.6%
** ETFs - United States Natural Gas Fund UNG.P and ProShares Ultra Bloomberg Natural Gas BOIL.P each down marginally
(Reporting by Pooja Menon in Bengaluru)
((Pooja.Menon@thomsonreuters.com;))