Glad you found the site. Unfortunately there’s not a good system to determine availability and we are independent of Costco so don’t have any special insight.
I know that some readers of the blog will use the item number that we list at the end of the reviews. They will either call the store and ask if they have that item number in stock. Or they will use the online chat at Costco.com to ask about the availability of the item numbers near them.