Page 1 of 1
Cyclone band cloud patterns [pics]
Posted: Mon Sep 04, 2006 10:52 pm
by FL Cyclone
On the picture of the below hurricane, what is that perpendicular fringing of the clouds along the leading edge/perimeter of the storm? I also found a recent floater IR image of the same type of cloud "spokes."

Posted: Wed Sep 06, 2006 2:57 pm
by wjs3
I was hoping someone else would take a crack at this, becasue I've only studied this once and think I might get parts of it wrong. Anyway...
I think those are transverse waves in the Cirrus clouds. I'm sure someone will help if I'm wrong in the exact naming.
The concept--at least with a tropical cyclone--is that when outflow gets established (remember that you can often "see" outflow in cirrus clouds over a TC), a wave pattern sets up that's essentially at right angles to the flow. (The atmosphere is funny this way--cloud patterns set up parallel to or perpendicular to the flow in places you wouldn't expect...cloud streets are a great example of this).
Anyway, with the TC, those waves are the rolls you're looking at .
Can anyone else build on this or correct me?
Posted: Wed Sep 06, 2006 9:08 pm
by FL Cyclone
You pointed me in the right direction. After some searching, if found this definition in an AMS glossary:
transverse cirrus banding—Irregularly spaced bandlike cirrus clouds that form nearly perpendicular to a jet stream axis.
They are usually visible in the strongest portions of the subtropical jet and can also be seen in tropical cyclone outflow regions.
Thanks for the reply.

Posted: Wed Sep 06, 2006 11:17 pm
by wjs3
Cool... I did better than I thought!