Hey man,
People told me the Comm. checkride was just a private checkride with some new maneuvers. It's basically true! The oral for me wasn't anything too complicated. I did my multi comm. at the same time, so that made it a bit more challenging. Take your time and just think logically. If it takes you a few seconds to think of the correct answer, don't sweat it. The examiner knows that patience is a virtue when he's waiting for your answer. If you're not sure, offer to look it up to show him you know where to find the info. I'm sure you've probably heard all this before...
The flying part is not very bad at all, assuming you're prepared - which I'm sure you are. If you're not happy with the way the maneuver is going, stop and ask to start over. My 8's on pylons sucked the first time, and I told the examiner I wasn't happy with the way they were going. I told him I was going to start over, and he said no problem. It's your test, take it into your own hands. You'll decide the outcome. Don't rush, and everything will turn out well at the end of the day! It's just a test, and it won't define who you are as a pilot. It will just give you one more story to tell at the end of the day - AND another certificate to put in your wallet!!!
As far as weather questions... as someone said earlier, each examiner is different. I stressed hardcore about my weather knowledge, and really didn't even have many questions about it. Know how to interpret an Area Forecast! That's all I got. Took mine 3 months ago, and now my CFI checkride is in 3 days! Can't wait to start workin! Take care and good luck my friend. Let us know how it turns out.