The National Weather Service warned yesterday that extremely dry conditions have increased the risk of fire in the Charlotte/Lake Norman area and much of the rest of the state. The alert served as a reminder not to burn those last-of-the-fall leaves on the ground. The practice is prohibited under the N.C. fire prevention code and Mecklenburg County air pollution control ordinance. “The low humidity and dry fuels will increase the fire danger,” the NWS office in Greer, S.C., posted on Twitter. “Fires may spread quickly and uncontrollably. Outdoor burning is discouraged.” The alert, in effect through Monday night, also covered Upstate South Carolina and the N.C. mountains, Piedmont and Piedmont-Triad.