Camp Muir this weekend (Interpreting weather forecasts for alpine environments)

If you've seen my Previous thread , You'll know that I am fairly new to backcountry skiing. So far most of my outings have been clear skies, with the occasional light drizzle in the lower alpine (Silver Peak). 
I was looking to do Camp Muir this weekend, however, most weather forecasts are calling for potential rain in the region on Saturday and Sunday. The weather forecast makes me uncomfortable in going due to the potential of the weather getting stormy and the near freezing rain/snow affecting the slope stability (I do understand that the snow field is fairly low angle). Similar conditions are predicted for Artist Point, which was going to be the backup. 

I'm looking for your interpretations and experiences with the weather forecast for summer skiing on the volcanoes.

Alternatively, does anyone know if Snow lake or something non-technical in snoqualmie goes? I might be able to sneak out on thursday or friday before the weather hits.

Weather sources I have been using:
NOAA
Mountain/Snow-Forecast
SpotWx

Thanks
Aaron

The best weather resource for Rainier is the custom forecast that they have:
a.atmos.washington.edu/data/rainier_report.html
The webcams on Amar's site are good, too:
www.skimountaineer.com/MtnWebCams/Rainie...ebCams.html?size=med
From the looks of it, it was cloudy and perhaps drizzly at Paradise, but sunny above the cloud layer. Not good conditions for navigating to Muir. There is also a very real hazard this time of year of falling or skiing into a creek hole. This would be easier to do in poor visibility.

Thanks,
Planning on going tomorrow (monday) for the sun.