Monitor service for 1hr; warning->critical at end of hour

I want to monitor a service over the course of one hour each day, waiting for the arrival of a critical file on the client. The check command initiates a script on the client via snmp, which looks for the file and returns a found or not-found. The check is now running fine when forced, and correctly indicates the arrival or absence of the file.

During that hour, I’d like to see the service in a Warning state if the file hasn’t arrived, then change to Critical at the end of the hour if there’s still no sign of the file.

My first thought was to monitor once every 10min, and go from Warning to Critical after 6 negative results. Here’s my first attempt at the service config parameters, but I think I’m off in the deep weeds:
check_interval 10
max_check_attempts 6
retry_interval 10

Any advice is appreciated. Thanks…Lyle