The satellite is able to detect these temperature differences by using an infared sensor. The information about the temperature of the clouds is sent to a ground based computer which creates an image which can, finally, be perceived by human eyes. We know, from observation, that clouds move with the wind. When viewing either satellite image we can see where the clouds are or aren't and make estimates about the clouds thickness. Look at the satellite images on the class website.
Coastal mountains stop coastal breezes from moving clouds Eastward.
The exception to coastal mountains stopping cloud movements depends on two things. The first is the presence of gaps in the mountains. The Golden Gate is a example of a gap that allows low lying clouds through the coastal mountains. The second thing would be if clouds are forming at altitudes and being pushed by winds that are higher than the coastal mountains. Use of such images has allowed meteorologists to learn, for example, a great deal about fog and its motion.