add_filter('tribe_events_pre_get_posts', 'filter_tribe_all_events', 100);

    function filter_tribe_all_events ($wp_query) {

            if ( !is_admin() )  {

                    $new_meta = array();
                    $today = new DateTime();

                    // Join with existing meta_query
                    if(is_array($wp_query->meta_query))
                            $new_meta = $wp_query->meta_query;

                    // Add new meta_query, select events ending from now forward
                    $new_meta[] = array(
                            'key' => '_EventEndDate',
                            'type' => 'DATETIME',
                            'compare' => '>=',
                            'value' => $today->format('Y-m-d H:i:s')
                    );

                    $wp_query->set( 'meta_query', $new_meta );
            }

            return $wp_query;
    }