Lik2hik, that's the same number I have for the Mammoth Ranger Station.
According to the Mammoth Mountain <a href="http://www.mammothmountain.com/">ski resort</a>, they've had about 4" of snow this week at 8500', so I would expect the trail to be passable at least as far as Shadow Lake and most likely all the way to Ediza.
One specific thing to ask the Mammoth Ranger Station, though, is the status of the Minaret Summit Road (Hwy 203) over the ridge past the ski resort and down to Agnew Meadows. I don't know whether they have officially closed it yet, nor whether they would do any plowing if it does snow more later this week or this weekend. If the road is closed, it's a couple of miles longer to hike than if you can drive to Agnew Meadows, plus quite a bit of altitude loss from the ridge down to AM and then back UP when you come out.
Watch the <a href="http://www.wunderground.com/cgi-bin/findweather/getForecast?query=mmh">forecast</a> and be conservative...a heavy snowfall could strand your vehicle until spring. Right now, it looks like it'll be warm enough that anything on Saturday will be rain, but keep an eye out...