Ever since the first images were produced in the 60s, Satellite based tools have continually improved.
The current West Coast Satellite is GOES-10. It produces 3 different products
1. A Visible image with 1km / pixel resolution (each pixel is the brightness of a 1x1 km square on the surface) . This daytime only image directly shows the cloud cover and fog. The GOES-10 satellite takes a single image of the entire Pacific basin. Various web sites extract portions of this image for display. The SJAA page presents a Navy image of just the Bay Area. U of Washington site can generate loops of portions of the image.
2. InfraRed or (heat image). This shows how hot the surface is. This contains a lot of information, but its interpretation is out of scope for this presentation. If you would like more information on IR satellite please consult the sources in the reference section of the web site. An important note is that IR images are available at night. They are have only 2km resolution.
3. A Water Vapor image. This shows the amount of water vapor in the air with black meaning there is little vapor. Dark areas in this image have low humidity. We will discuss the implications of low humidity later in the presentation. They have 4Km resolution