Thanks astro_bot - that's exactly where I get my jetstream info from. It takes a little practice to understand what they're saying, but it's not rocket science :-) Today's chart shows there are still 100-140kt winds from 30k ft and up :-/// I'm not an expert, but IMO 140kt = badness
That said, it doesn't stop me getting my scope out, it just helps greatly with expectation management of what I'm going to see
You can actually 'see' the jetsteam in your eyepiece if you defocus slightly; it looks like a bunch of rapidly flowing, closely spaced parallel lines.