Posts: 29
Joined: Tue Feb 27, 2001 12:44 pm

Cloud Tops

Tue Feb 27, 2001 12:52 pm

I am looking for pilot information on cloud tops. I can find ceiling data easily, but nothing pertaining to at what altitudes those clouds cease. Can someone help me out?

Posts: 3960
Joined: Fri Aug 25, 2000 1:18 am

RE: Cloud Tops

Tue Feb 27, 2001 2:40 pm

It depends on the type of cloud... cumulonimbus clouds are clouds with extensive vertical development and can start at 3000 feet and go all the way up to 60000 feet if they are severe.

I have never really seen cloud top data except on thunderstorms and also they will usually tell you if there are layers... try checking the PIREPS..those sometimes have cloud top data.

Chicks dig winglets.
Posts: 18919
Joined: Mon May 08, 2000 11:19 am

RE: Cloud Tops

Tue Feb 27, 2001 2:45 pm

If you can get access to a NEXRAD radar site, you can find out cloud tops there, in various ways.
Red Panda
Posts: 1433
Joined: Wed Jun 14, 2000 12:58 pm

RE: Cloud Tops

Tue Feb 27, 2001 4:57 pm

Ceiling (cloud bottom) is much more well known than clould tops. As a matter of fact, cloud like cumulonimbus can extend vertically in a very short time say an hr. It's sometimes hard to predict the cloud tops. I was once on NW11, DTW to NRT, the pilot just told us that we had to increase altitude since there was cloud developing just beneath us. I can see that we were flying along the edge of cloud top and there was quite strong turbulence. I can actually feel the plane increasing its altitude rapidly. (my ears got sick)

r panda
Posts: 1066
Joined: Fri Mar 16, 2007 1:29 pm

RE: Cloud Tops

Tue Feb 27, 2001 10:55 pm

In an ISA (ICAO Sstandard Atmosphere), the tropopause is between 35,000 and 36,000 feet. It is usually defined as the level of maximum wind. At the trop, the temperature should also stop decreasing. Close to the equator (up to +/- 23.5 degrees depending on season) the trop is at its highest height; close to the poles, at its lowest.

Normally CB tops don't exceed the tropopause. However, during periods of extreme vertical activity, the tops may exceed the trop quite dramatically.

I have seen CB tops in excess of 70,000 feet in the south Pacific; and tops in excess of 50,000 feet in Alberta!

Volcanic plumes can also well exceed the trop.

Best Regards,