Dan Martin, 63, has been drawing the Weatherbird on a daily basis for 35 years. This interview will be on “St. Louis on the Air” over the noon hour Tuesday. This story will be updated after the show. You can listen live. Every evening, just as many people are shutting down their computers for the day and starting to think about supper, Dan Martin is gearing up to complete his daily drawing for the St. Louis Post-Dispatch: a fresh depiction of the newspaper’s Weatherbird. The artistic process gets going once the news editor sends him a budget around 6 p.m., summarizing plans for the next-morning edition of the newspaper’s front page.