Hi Bill, and welcome to the forum.
As a fellow Mac user, I understand the frustration in trying to find a good solution.
WeatherSnoop is a nice little application for presenting the your local conditions on your Mac. However, you still need some way to get the data from your weather station to your Mac. Does the Ambient package have some sort of data logger or connection to get it there? Or is the receiver/console wired directly to the Mac? I played with WeatherSnoop a bit but I didn't have a station yet, and then the next time I tried WeatherSnoop I already had the Davis data logger. WeatherSnoop will send your data to Weather Underground,CWOP, and WeatherBug.
A few of us here with Macs use Lightsoft Weather Center. Here's a thread describing it in a bit more detail.http://www.wxforum.net/index.php?topic=8545.0
The guys on the MacWeather.net forum mostly seem to use Davis, Oregon Scientific, and LaCrosse weather stations. Even if you don't get LWC, stop in ther to discuss Mac specific problems. I use both forums a nd find they compliment each other nicely. This has a lot more hardware and knowledge and the MW forum has the Mac side covered.
Hope that helps,
(you can peek at my site in my sig to see an example output from LWC's custom web template, but the data is stale, as my hard drive croaked yesterday...)