Updated April 16, 2014 to reflect the new conference.weather.im XMPP server.
Many years ago, the Iowa Environmental Mesonet at Iowa State University established iembot, a service that relays National Weather Service products from each forecast office in real time. iembot messages are available using a Web-based interface, via Twitter (for example, I follow to receive products from the National Weather Service in Charleston), or via XMPP. While I’ve used all three methods, I far prefer XMPP — nothing beats the immediacy of receiving important messages in an IM client, and for me, weather messages certainly fit in that category. Thanks to Growl and Adium, two excellent (and open source) pieces of software that really make the Mac worth using, I’m able to do a number of cool things with the most important messages: sound an alarm, speak out the text of the alert, and even send a push notification to my iPhone when I’m not around (using another app, Boxcar, which has a Growl plugin).