Hi Karl.
I use a weather service called yr.no (www.yr.no). They provide weather data for free. And they have a "now" feature that monitors rain and snow for the next 90 minutes.
This is available in a xml file/site.
http://www.yr.no/sted/Norge/Vest-Agder/Vennesla/Vikeland/varsel_nu.xml
I use the GhostXML plugin and have the different states in a device. Is it possible to plot this with your plugin to make it look something like the picture below?