I just flew out of AMS yesterday, connecting from DUB. The weather was crappy - in fact, I'm pretty sure (but not positive) that our Aer Lingus pilot tried to land the plane, but couldn't. We eventually did. A 1.10 hr flight turned into 1.5 hr. It was super cloudy and raining.
I didn't go through any customs check until boarding my connecting flight, and a woman that looked exactly like Oprah asked me like 6 questions and then let me through. I think you should be fine with 50 mins, but that's if your flight into AMS isn't delayed.