It looks like S.M. does not anticipate the clouds, it draws them when we're only few miles or entering into the systems. They will disapear when we're out of them. Since I have the distance vie in high, it results in clouds systems appearing and disappearing on the flight at areas where I did not expect since it did appear to be VMC from the distance. Is there anything to set about it ? As another example, from John Wayne (KSNA) to San Cataline (KAVX), few at SNA, SCT on he way and OVC at AVX : Taking off from John Wayne, I have few cumulus, I travel around them, climb, soon they all disappear and I can see the whole area including the airport free from clouds since I'm now flying in a local area that's completely free from clouds. In the distance, I see over the water, San Catalina far away, it's all VMC. I travel along to AVX, on the way it's becoming few, then OVC below me and the coverage goes for all the area from coast to AVX. As checked from the weather map. Real weather available was few at SNA, clear west SNA, few on the coast, ocv overwater including AVX. Visually, it's not possible to identify those areas as they appear and disappear once I fly into them (say 30 seconds flight from the area, it would change according to it).