Yes, because in your scenario I'm assuming the airspeed would also drop and the short version is that the A/P disconnects (@ alpha protection +1 degree for airbus). If speed decreases fast, and below alpha protection, and beyond the ALPHA FLOOR threshold, the A/THR commands TOGA. In this scenario the autopilot could of course also disconnect earlier due to the turbulence caused by the updrafts but that would ultimately not change how the FBW would react to the loss of airspeed.
There are lots of variables affecting the various speeds, thresholds etc etc, and it could be discussed and debated forever, but that's the simple version.
As always with the FBW threads you can count on this one to also turn in to pages and pages of Boeing vs Airbus and at least 200 versions of what would happen and how the aircraft would react in case of, and what if etc etc.
Last edited by CaptainProp; 1st Jan 2015 at 08:55.
Reason: Wrote faster than my brain could manage. As correctly pointed out, pitch down command is active in ALT law