NTP is not designed to track anything except the one true time, so this setup is not guaranteed to work.
However, if you stop NTP, set your clock manually to the desired time, configure NTP with the local clock driver as its sole source, and start NTP again, it should use that time.
The clock driver selection should be as follows:
server 127.127.1.1 iburst prefer
fudge 127.127.1.1 stratum 0
And you should ensure that there are no other peer
, pool
, or server
lines present in your configuration.
Note that this will make your system subject to the inaccuracies of your local clock, which is not recommended.
Note also that NTP always works in UTC, so the local time zone has no relevance. It's used for display only.