High pressure systems are normally correlated with stable atmospheric conditions with little to no cloud cover, but due to this minimal cloud cover, doesn't that open up the ocean / ground moisture to evaporate to then later condensate to form clouds?
I understand there are other forms of cloud formation like subsidence or frontal uplift, but some days here in Perth are very still and there hasn't been any fronts recently. For example during today (27/12/2021), it has been very still yet the heat has reached 40°C. For the previous two days there has also been temperatures reaching up to 45°C for prolonged periods of time with clear skies. I haven't felt much wind or any down drafts within my vicinity.
Today, there has been altostratus, altocumulus and cirrus clouds. Most of the clouds are isolated but some have formed extensive 'clumps' of cloud coverage with other clouds. So despite the high pressure system is it possible for there to be a decent amount of cloud generation? Can the ocean evaporate despite there being descending air? 
