Cacher is the code snippet organizer for pro developers

<?php

function university_adjust_query( $query ) {
	// Only run if on front end of the site
	// This query only run on our intended URL
	// $query->is_main_query() is making sure that we are only effecting the default query not any custom queries we may have written

	if( !is_admin() && is_post_type_archive( 'event' ) && $query->is_main_query() ) {
		// $query->set('name-of-the-query-parameter-you-want-to-change', 'value-you-want-to-use');
		$today = date('Ymd');
		$query->set('meta_key', 'event_date');
		$query->set('orderby', 'meta_value');
		$query->set('order', 'ASC');
		$query->set('meta_query', array(
			array(
				'key' => 'event_date',
				'compare' => '>=',
				'value' => $today,
				'type' => 'numeric'
			)
		));
	}

}
// Right before getting the posts
add_action( 'pre_get_posts', 'university_adjust_query' );