you might want to give this a read:
http://www.nar-associates.com/techni...ide_screen.pdf
the available lift increases with speed squared.
if we assume that the turbulence increases the angle of attack a non-speed-dependent amount additional lift due to turbulence is reduced proportional to speed squared.
now at a higher speed the absolute angle of attack increase due to a change in vertical windspeed (updraft) is less.
so our previous assumption is not very helpful and i'd say the updraft induced additional lift is proportional to speed.
but and this is the big thing: the maximum available lift at the stall angle of the wing is proportional to the speed squared.
therefore if your wing temporarily stalls due to an updraft the total lift available increases with the speed squared.
the additional lift due to the updraft decreases even more dramatically approaching stall speed.
but as the linked pdf describes you normally fly a comfortable speed at which the wing at maximum AOA can't rip your wing apart and you are still fast enough for good controllability.
EDIT:
reading the other pdf linked ..... what i linked seems like it would not apply to jet transports
stalling might be good if it's the only way to keep your wing from falling apart but the accompanying loss of control is really bad.