The coldest air in almost 20 years is sweeping over the central U.S. toward the East Coast, threatening to topple temperature records, ignite energy demand and damage Great Plains winter wheat. Chicago’s high today won’t reach zero Fahrenheit (minus 18 Celsius) and may just hit that tomorrow, according to the National Weather Service . New York City ’s low will fall to 8, Washington will see 5 and Dallas ’s low will be 19. Orlando , Florida , may drop to freezing at 32 degrees. For the East, tomorrow will be even worse. Winter storms and frigid air add volatility to commodities trading and spot power markets. Natural gas futures in New York have surged 23 percent since Nov. 1 as the coldest start to the U.S. heating season in 13 years boosted fuel demand. Last week, as snow and cold gripped the nation, spot power […]