U.S. natural gas prices started the week with a further slide, after ending last week lower, as meteorologists predict warmer-than-usual weather ahead. In early morning Asian trade today, the U.S. benchmark traded at $3.20 per million British thermal units, down by 6.5% from Friday, when prices shed 2.5%, after a three-day climb earlier in the week, Bloomberg reported. Official weather forecasts say the cold spell is over and warmer weather will spread across much of the United States towards the end of this week. Earlier in the year, natural gas…