CHICAGO (AP) - A cold front broke the heat wave Sunday across much of the Midwest, but the death toll kept climbing as authorities counted the victims from a week of torturously high temperatures and humidity. Chicago authorities added 30 names to their list of heat-related deaths Sunday and said they were sure the number would go even higher. That brought the Illinois total to 80 and the nationwide number to at least 182 since July 19. Sunday's temperatures were 10 to 20 degrees cooler than the previous several days across the Great Lakes and much of the upper Midwest. Chicago warmed to 81 by early afternoon, compared to a high of 104 Friday. Three heat-related deaths had been reported in North Carolina, where high temperatures pushed toward 100 again Sunday.