This moisture, while not seen in either the visible or IR image, will be readily observed in the water vapor imagery.
In this image, you will see moisture extending from southern California and Arizona northeast into southern Canada.
On the corresponding visible image (mouseover the image) the actual cloud cover is limited over southern California but the supply of moisture helps fuel the showers and thunderstorms in Minnesota.
Advantage: Dark areas shows the moisture level in the atmosphere is low.
You can see areas of rising and sinking air in the atmosphere. Sinking air (dark areas) indicates ridging and does not support the development of precipitation. The moisture, indicated by the gray and white areas also shows rising air which can lead to the formation of precipitation.
Disadvantage: This image cannot "see" below about 10,000 ft. (3000 m) elevation due to the absorption of the heat energy by the atmosphere.