I agree with Notso, but also with wsherifs "Unless the resultant angle of the aircraft's forward momentum and the vertical component of the updraft increases the lift and moves the center of lift forward on the swept wing. pulling the nose up."
Is it possible that the personal experience was a downdraft? How can you confirm it was an updraft if you maintained altitude?
And, from the other side, against "if an updraft pitches an aeroplane nose up, then it will diverge and the pitch up moment will continue" - updraft against an aircraft which is nose-up will also add a tailwind component, which would bleed airspeed and initiate a pitch down motion.. would it Notso?
I'm happy to be corrected, of course (and I don't mean that as in "come on then!" - honestly!!
)