Rich,
I don't remember SMS in LWC, but I've been on WeatherCat since January, and that's a long time ago to remember.
I wouldn't have used the SMS feature, so it might have been right in front of my face and I never noticed it.
You can also have the rain alarm launch an application, so you could trigger a siren sound loop, or a very loud recording of yourself saying "Go get the clothes off the line, wench!" and then run for cover. Or maybe not...
Glad you got things up and running,
Steve