Label Parameters
In addition to the Label A and B parameters available in the Current Observations part, the Label C parameter is available in the Weather Forecast part. It is used to provide a method of returning any arbitrary text. Any allowed URL encoded string that is 31 characters or less is allowed. URL encoding normally replaces a space with a plus + sign or %20. More information on URL Encoding can be found at the HTML Uniform Resource Locators web page.