Can I throw a question in here for the technically-minded?
Initially, Notso's thesis made perfect sense to me. However, it occurs to me that, in most modern aircraft, the centre of gravity is aft the centre of lift (thus necessitating a net downforce by the tailplane).
A strong updraft would act primarily on the CofG, n'est ce pas? thus making the initial response by the aircraft a nose-down pitch.
Or am I talking a load of whatsits?