Can you write an LDAP query that returns accounts modified in the previous day?

I have a system that synchronizes from a master LDAP store. The synchronization process has gotten longer and longer as our directory grows. I had to stop syncing hourly, and moved it to an overnight schedule. But this results in more 'you have an account but I can't see it yet' problems.

I would like to add a parameter to the LDAP query that tells the system to only pull records modified in the past hour, and run it twice an hour; efficient and convenient. Unfortunately I can only find out how to filter on an absolute timestamp, such as (modifyDateStamp>=201311210000.u), but not a relative time. The system we are using cannot build a dynamically created query, so I can't generate a new UTC timestamp every time it runs.

The answers in this question only mention using the UTC time, so I am pessimistic. Is there a solution?