http://www.ghcc.msfc.nasa.gov/GOES/goes8hurr.html

There's the link to the Visible. If you see this before the Atlantic darkens with night fall, you should see exactly what I was trying to say. Look south of 20 degrees north and between 40 and 60 degrees west. Also, it will help if you click the 'animate' button.

http://www.ghcc.msfc.nasa.gov/GOES/goes8hurrwv.html

That link is for the water vapor. Where it's pitch black, there is little moisture in the atmospher.

Steve