I'm more worried about gusts than wind strength. If it's a gusting crosswind I'd hesistate to go flying if the winds are above 10 - 15kts (although I have landed in worse).
If its straight down the slot I'd be happy(ish) with a 20kt steady wind, much more than that and you can bank on it being pretty bumpy aloft.
I had one memorable experience last year where I launched into 30 - 40kt winds aloft (worse than forecast). I ended up having to divert as couldn't get back to my home field (the wind direction veered after I'd departed and the cross wind component was way beyond what I'd be comfortable with). It was a good learning experience but far from enjoyable, and not something I'd want to repeat.