I wouldn't call this official beta, but here is my take on the Central Cascades for this summer. Please disregard if some Bend folk stop by and leave a post as they can immediately check on conditions and I am going off what I saw a month or so ago.
Myself and a friend went on our second climbing trip though Oregon this past July. We intentionally went a month later to avoid the big snow we had run into the year before. We climbing mostly in SE Oregon, but hustled up to La Pine and did Paulina Peak (and went over to Crater Lake too). (Note: Here we had planned to do Bachelor and Ball Butte...which after seeing them...we laughed and headed South, granted we had ice axes...but no crampons)
The snow was still fairly heavy as of July 5th (when we did Paulina). Half of Crater Lake was still closed. Basically we ran into the same quantity of snow we had faced the previous year, but three weeks later than the previous year. As far as I know, when I left the Northwest (two weeks ago) we had still not had the usual heat wave I'm used to (90s to 100s for a week or two) and a quick look at the weather channel apparently agrees http://www.weather.com/outlook/weather-news/news/articles/zero-for-90-in-2011_2011-08-17
In summary the point is 1) this was an unusually heavy snow year for the northwest (Oregon included) and 2) this was one of the mildest summers in recent years as far as heat is considered in the northwest. My guess is to expect snow still at elevation around the South Sister and Broken Top. This by no means is a typical Central Cascades August/September where you can waltz up the South Sister (did that September 12, 2009) with out a patch of snow till you hit the crater. (I'm assuming you are climbing something there and would like to scramble or hike to the top). If you are just planning on heading up to 7k or 8k and a lake you are probably fine, but if you are planning on climbing something come prepared for snow.
That is my take hopefully you can get a current diagnosis on conditions.