The extended forecast is here. Last week, the 10-day forecast called for mid-90 highs and bright sun on Saturday the 30th. Over the weekend, they were predicting highs in the mid-80s with a significant chance of thunderstorms.
I have my eye on the forecast, but I am still considering it a rain or shine event. My tent is waterproof and I've commuted in the rain before. In the summer, I actually like riding in the rain. Obviously, it'll be a safety first kind of deal, and we may delay the departure for a few hours if we feel the impending storm will be too dangerous.
We're still on, though.