Natural gas futures prices came crashing down Friday as weather models all trended warmer for the rest of December, easing some fears about adequate supplies this winter. The Nymex January futures contract plunged 29.7 cents to $3.827, the first sub-$4 settle for the January contract since Nov. 12. February dropped 27.4 cents to $3.753, and March tumbled 25 cents to $3.606.