After about 15 sec. we encountered moderate rain. We thought it odd to have rain streaming up the windshield at this altitude and the sound of the plane getting pelted like an aluminum garage door. It got very warm and humid in the cockpit all of a sudden.
What would explain that the air became warm and humid all of a sudden?
There's no outside fresh air being blown directly in the flight deck obviously, so would the icing have also affected the packs operation? Could the heat exchangers have taken ice?