https://www.facebook.com/groups/advancedwp/permalink/2208828812512654/

pre-get-posts.php

<?php
function action_pre_get_posts( $query ) {
  if ( $query->is_tax() && $query->is_main_query() ) {
    $meta_query = array(
      array(
        'key' => 'date',
        'compare' => '>=',
        'value' => date( 'Ymd' ),
      ),
    );
    $query->set( 'meta_query', $meta_query );
  }
}
add_action( 'pre_get_posts', 'action_pre_get_posts' );