May Nymex natural gas (NGK26) on Tuesday closed down -0.003 (-0.10%). Nat-gas prices tumbled to a 5-week low on Tuesday and settled slightly lower.   The outlook for above-normal US spring temperatures, which will reduce nat-gas heating demand and boost storage levels, is weighing on gas prices.  However, nat-gas prices recovered most of their losses on Tuesday when the Commodity Weather Group said forecasts shifted colder, although above-average temperatures are still expected across the eastern half of ...