My Ubuntu server is EST, but all times in Jira are UTC.
You need to add a JVM parameter:
Add this to the JAVA_OPTS variable in setenv.sh (or setenv.bat if you're on Windows) in the bin subdirectory of your installation and restart JIRA.
It's a good practice too keep all the systems on UTC, database and servers.
The only place where people should use the local timezone is the last step, the client.
Otherwise sooner or later you will reach the point where you get the datatime altered, especially when migrating data.