Natural-gas futures jumped nearly 10% Tuesday on expectations another wave of colder-than-average weather will generate even more demand for the heating fuel. Households across the Midwest and Northeast have consumed record amounts of natural gas this year amid frigid temperatures. Forecasters are calling for cold weather to persist through mid-February, with some predicting below-normal temperatures into March. The resulting spike in heating demand has revived the formerly sleepy gas market, sending investors scrambling to exit from bets that prices would stay low and into new wagers that futures will rally further. On Tuesday, natural gas for March delivery shot up 9.6%, to $5.375 a million British thermal units. Futures are within striking distance of a four-year high of $5.557 set last Wednesday. Traders and analysts say it is a return to traditional trading patterns for a commodity that was known for big price moves before a surge in […]