Because you turned the cabin blower off and the noise was still there, I would look at the serpentine belt for the primary cause. You did say it was a bit wet outside, and water can cause that belt to slip.

Unfortunately, this is a relatively new car, as is the belt. Fashion a stethoscope and with the engine at idle, and aware of the moving belt, check for vibrations from the rollers, AC, and PS pump. Any vibration is a no-no.

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Keeping it running is better than buying new