Figured it out:
<?php
$today = date('Ymd');
$args = array(
'post_type' => 'hh_event',
'posts_per_page' => -1,
'orderby' => 'meta_value',
'meta_query' => array(
array(
'key' => 'event_date',
'value' => $today,
'compare' => '>',
),
),
'order' => 'ASC',
);
$the_query = new WP_Query($args);
?>