an example of a good memo (i'm really into the essential clause):
To Denver Campus Faculty, Staff and Students
From The Denver Campus Emergency Management Team
Date Dec. 22, 2011
Re Weather-Related Closure for the Denver Campus
Due to the heavy snowfall in the Denver metro area, the Denver Campus will be closed today, Thursday, Dec. 22, 2011. All personnel who are considered essential must make every effort to report to work, despite weather conditions. Please confirm directly with your immediate supervisor as to whether or not you would be considered essential personnel under such circumstances.