Visible Water Vapor - US 3 hr Loop
The water vapor image show an infrared band which is affected strongly by the presence of water vapor. Essentially, the image shows the altitude of the highest moist layer in the atmosphere. Bright areas reflect the location of high clouds either due to jet stream cloudiness or due to thunderstorm activity. The dark areas reflect the location of dry air at high altitudes. This is associated with dry air intrusion and sinking motion associated with high pressure systems. This image is a decent tracer of jet stream winds which will show up as bright streaks.