March Nymex natural gas (NGH24) on Friday closed +0.028 (+1.77%). Nat-gas prices on Friday posted moderate gains as forecasts for colder weather in the U.S. sparked short-covering in nat-gas futures. Forecaster Atmospheric G2 said Friday that above-normal temperatures will end as “seasonably cold air spills into the eastern half of the U.S.” from Feb 21-25, which will boost heating demand for nat-gas. On Thursday, nat-gas prices plummeted to a 3-1/2 year nearest-futures low on warm U.S. winter weather, curbing heating demand for nat-gas and pushing supplies higher. As of February 9, U.S. nat-g…