I can imagine two explanations: 1) Scotty is beaming water molecules into the attic every morning and beaming them back out every
afternoon at the exact
rates to mimic a capacitance charge - discharge curve; 2) or, more likely but less entertaining, the water molecules are going from the ad and absorbed state in the exposed porous materials into the attic air in morning as the sun hits the roofing materials and
drives water vapor out of the sheathing, rafters, open cell foam into the attic air.