...in your scenario I'm assuming the airspeed would also drop
I’d have thought it would have been the opposite.
When you encounter an strong updraft, the *immediate* effect is for the IAS to increase along with the effective AoA.
This can have several results. If the resultant AoA is high enough, the wing section will stall (but still be generating significant lift). If it doesn’t stall, then there will be a marked increase in lift which may overstress the structure, depending on the airframe limiting load factors described by the flight envelope.