NEW YORK –Broadway grosses dropped for the third week in a row as warm weather kept audiences out of doors. Total B.O. for Week 50 (May 7-13) slid to $14,170,574, a small decrease of .8%. Total attendance was 261,007, just a fraction of a percent below last week’s.With four more box seats now being sold at each perf, “The Producers” hit its highest note yet, $1,020,544, an increase of $7,160 from last week out of a gross potential of $1,022,031. The closing of four shows began the annual seasonal winnowing of the Broadway roster. “The Adventures of Tom Sawyer,” “The Gathering” and “Judgment at Nuremburg” all gave up the ghost, while the Roundabout Theater Co.’s limited run of Noel Coward’s “Design for Living” also came to an end. Some shows saw big drops, notably “Seussical,” which lost more than $200,000 and fell to $280,924 after several weeks of notably healthier business. The 25 musicals totaled $11,545,795 for 81.4% of the Broadway returns, with paid attendance of 204,985 at 74.7% of musical capacity. The 12 plays totaled $2,624,779 for 18.5% of the Broadway total, with paid attendance of 56,022 at 62.8% of play capacity. Average ticket prices were $49.76 for all shows, $50.23 for musicals and $41.04 for plays.