Utilize the Alert App to display a light-box style pop up message on any page. App options include the ability to add a library or custom icon in addition to text via a WYSIWYG editor. When a user closes the alert dialog, it will not display for them again until they clear their browser data or close their browser completely and revisit the web page in a new browser session. If you want your alert message to show on the page each time the user visits, simply check the box to make the alert "persistent." Other options include the ability to set a duration display and control the width of the alert box. The Alert App can be placed on any page and in any content region.
Pro Tip: This app can be used to promote a variety of content - weather related closings and delays, time sensitive information with a deadline, upcoming events, important announcements, etc. Because the user has to acknowledge the dialog box before accessing the page content, there is little chance that a user will miss the content. Just be sure to use this app appropriately and reserve it for your most important content.