There are two possible reasons for "strange" take off.
First one. I am a common visitor at Madrid Barajas airport (i live in the area) and I´ve noticed that many times when rwy 15 is being used for take off the big aircrafts make an early left turn...well, in this case it could be too early.
The other reason could be a strong wind gust. There is another picture in the database of an Airbus A340-600 taking off from the same runway the same day at about the same hour. It´s barely off the ground and you can see the effects of strong crosswinds we had at Madrid a few days ago.
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Photo © Ismael Jorda
There could be a third reason: maybe the pilot saw a nice girl taking a shower under the rain and he just wanted to have a better view!!