In contrast to the forecast bulletins, which are emitted regularly, the warnings and advisories have two particular features that set them apart in how they are handled. On one hand, they are not emitted regularly, but only as needed and, secondly, they ``expire''; i.e., they must (or should) be ``purged'' from the system after the some date-time. There is a technical difference between the expiration and purge times, which I will not explain here; the interested reader may wish to consult the official documents where these things are explained.
The obvious problem that this brings up to software developers is how to process this kind of bulletin, taking those two aspects into account, in particular the purging requirement. Following what we do in the rest of our system, we process this type of bulletin through a (unix) filter written, in this case, in ruby. Ruby is a nice language, with the power of perl and the expresiveness of python. Anyway, our setup is to make a pass every hour through all the installed warnings and advisories to check if their purge time has passed, and take the appropriate action (i.e., purge it from the system) if the criteria are met.
Therefore, under good working conditions, our system will not show outdated or expired warnings and alerts, only current ones, except for the one-hour window between the purge checks. If it does not work as described, it is a bug in our system. And if the page shows that there are no current bulletins, it should mean what it says. Which brings up the next question.
Several places (i.e., sites) have links or copies of the official warnings and advisories, of course. However, in many of them, the bulletins are not purged, and in some of them they are in fact accumulated. Although that may be useful for some purposes, that brings the problem that you have to check yourself each and everyone of the bulletins to see whether they are current or not. To me, as a user, that is annoying. I like to see a listing of only the current bulletins, not a listing of all the possible bulletins that may be sent at any time, much less a listing in which I have to check (by following the approriate link) each bulletin individually to see if it is current or not. As it has happened with other pieces of the system that we have set up, this one also is the product of a personal frustation and an attempt to overcome that.