What type of clouds are the most turbulent?

[ZUKO]

Cumolonimbus or towering cumulus?

[bdhill1979]

The suffix nimbus just means rain, the taller the cumulus, the higher the updrafts are reaching, meaning a more powerful downdraft. Turbulence is something else entirely.

[ZUKO]

Originally Posted by bdhill1979

The suffix nimbus just means rain, the taller the cumulus, the higher the updrafts are reaching, meaning a more powerful downdraft. Turbulence is something else entirely.

Meaning since the cumulus is higher in a towering cumulus, then turbulence is greater. bah. I got it wrong.

Another question that I struggled with. Is high pressure associated with what type of weather. I thought it was usually good weather but not always.

[bdhill1979]

Originally Posted by ZUKO

Meaning since the cumulus is higher in a towering cumulus, then turbulence is greater. bah. I got it wrong.

Another question that I struggled with. Is high pressure associated with what type of weather. I thought it was usually good weather but not always.

cumulus is just a type of cloud, towering or not they are the same type of cloud. To create a "towering cumulus" there myst be a lifting force, i.e convection. As that cloud climbs higher and higer the lifting force becomes weaker and eventually that rising air must fall, creating a downdraft. The higher it went, the further it will fall, generating a greater force.

Turbulence is something different entirely, turb is unstable air caused by the uneven heating of the earth surface and other factors. Turb is associated with convective activity, but I would not consider a the inside of a towering cumulus to be turb, it is much worse.

[ZUKO]

Originally Posted by bdhill1979

cumulus is just a type of cloud, towering or not they are the same type of cloud. To create a "towering cumulus" there myst be a lifting force, i.e convection. As that cloud climbs higher and higer the lifting force becomes weaker and eventually that rising air must fall, creating a downdraft. The higher it went, the further it will fall, generating a greater force.

Turbulence is something different entirely, turb is unstable air caused by the uneven heating of the earth surface and other factors. Turb is associated with convective activity, but I would not consider a downdraft to be turb, it is much worse.

This question was on my block exam today. Which cloud is most associated with turbulence?

And I was stuck between those two and Im not sure what the other two choices were.

hmm Do you know if there is a type of cloud that has the heaviest turbulence? I studied sooo hard for this ground test and I dont think it is going to show when I get my results. Ever feel like what you put in does not equal what you get out?

[bdhill1979]

That is kind of a bogus question, because they are the same type of cloud, one just has a lifting force associated. If those were the only two then definately go with the towering cumulonimbus, the taller they are the stronger they are. Both are a hazard to be avoided by aircraft, but the towering variety definately are the greater hazard.

[Chris_Ford]

Standing lenticular for the win!

[bdhill1979]

and the dunk from ford, but I dont think the question was talking about mountain wave turb

[ZUKO]

Originally Posted by bdhill1979

That is kind of a bogus question, because they are the same type of cloud, one just has a lifting force associated. If those were the only two then definately go with the towering cumulonimbus, the taller they are the stronger they are. Both are a hazard to be avoided by aircraft, but the towering variety definately are the greater hazard.

Thanks. My ground school teacher loves confusing questions.

[bdhill1979]

All this talk made me get out my aviation weather book "FAA ac00-6a".

[bdhill1979]

Originally Posted by ZUKO

Thanks. My ground school teacher loves confusing questions.

Did your teacher write these questions or are they from a manual or book?

[bdhill1979]

Cumulus: Fair weather cumulus clouds form in convective currents and are charachetized by relatively flat bases and dome-shaped tops. Fair weather cumulus do not show extensive vertical development and do not produce precipitation. More often, fair weather cumulus indicated a shallow layer of instability. SOme turbulence and no significant icing.

Towering Cumulus: Towering cumulus signifies a relatively deep layer of unstable air. It shows considerable vertical development and ahs billowing "cauliflower" tops. Showers often result from these clouds. Very strong turbulence; some clear icing above freezing level.

Cumulonimbus: Cumulonimbus are the ultimate manifestation of instability. They are vertically developed clouds of large dimensions with dense "boiling" tops often crowned with thick veils of dense cirrus (the anvil). Nearly the entire spectrum of flying hazards are contained in these clouds including violent turbulence. They should be avoided at all times! This cloud is the thunderstorm cloud.

(copied from "Aviation Weather")

[meritflyer]

Just off the top of my head I'd have to say CBs are more turbulent as they are more often associated with a more developed thunderstorm and associated with extremely unstable atmosphere. While TCUs are definately turbulent, they signify the early stages of convective build up with predominately updrafts. CBs are high in moisture content and can be between the cumulus and mature stage of a thunderstorm.

I'd say CBs will present more up/down/horizontal shears and drafts just as it is more indicative of more organized or developed storm and may present more of a hazard to nearby aircraft.

[ZUKO]

Originally Posted by bdhill1979

Did your teacher write these questions or are they from a manual or book?

My teacher wrote these questions and the rest of the confusing questions.

I studied every day since monday for at least 2 hours each time. Some times up to 4 hours. And I met with my CFI 4 times in the last week to go over the material. :|

So in your book is violent stronger then very strong?

[bdhill1979]

Definately violent beats "very strong" Quote it if you want, it is from the FAA. Keep in mind that these are all manifestation of the same "type" of cloud, just in different stages of development.

[ZUKO]

Originally Posted by bdhill1979

Definately violent beats "very strong" Quote it if you want, it is from the FAA.

Thank you.

[surreal1221]

CB's are the strongest of any cumulus clouds. . .

/weather guy departing right now.

Originally Posted by bdhill1979

That is kind of a bogus question, because they are the same type of cloud, one just has a lifting force associated. If those were the only two then definately go with the towering cumulonimbus, the taller they are the stronger they are. Both are a hazard to be avoided by aircraft, but the towering variety definately are the greater hazard.

AAAH!! Wrong. There is no such thing as a Towering Cumulonimbus. There is Towering Cumulus, and Cumulonimbus. End.

There are 27 states of the sky. L2 (Towering Cumulus) is far less violant than L3 or L9 (CB or CB with Anvil or Mamatus observed). L standing for Low etage.

Both of these clouds are convective in nature, but it is important to realize and understand that a Towering CU does not have LTG or Hail associated with it, where as a CB does. So no. . . the "towering" variety is not the greater hazard. Yes they are both Towering cumulus cloud types, but a TCU is the second stage of a mature thunderstorm or CB. First stage is the cumulus stage, then towering cu, then CB. CB > TCU. The End.

If I really have to break it down further, I'll shoot myself.

/weather man out for good.

[the_dmn8tr]

The question is also, like 50% of the other questions on the test (Pg 205 #40 to be exact), from the Gleim Private Pilot book, which means the FAA wrote the questions and they are possibly on the Private Pilot Written exam. If you don't already have the Gleim book, I would recommend shelling out the $15. It is a great study tool for both the block exams and the Private Pilot Written.

[bdhill1979]

Originally Posted by surreal1221

CB's are the strongest of any cumulus clouds. . .

/weather guy departing right now.



AAAH!! Wrong. There is no such thing as a Towering Cumulonimbus. There is Towering Cumulus, and Cumulonimbus. End.

There are 27 states of the sky. L2 (Towering Cumulus) is far less violant than L3 or L9 (CB or CB with Anvil or Mamatus observed). L standing for Low etage.

Both of these clouds are convective in nature, but it is important to realize and understand that a Towering CU does not have LTG or Hail associated with it, where as a CB does. So no. . . the "towering" variety is not the greater hazard. Yes they are both Towering cumulus cloud types, but a TCU is the second stage of a mature thunderstorm or CB. First stage is the cumulus stage, then towering cu, then CB. CB > TCU. The End.

If I really have to break it down further, I'll shoot myself.

/weather man out for good.

You are correct, I had an instructor that always called them "Towering Cumulonimbus", that is still screwing with me.

[B767Driver]

Originally Posted by ZUKO

I thought it was usually good weather but not always.

One weather event you'll want to watch for with a strong high pressure system is widespread fog. The convergent air, coupled with high moisture content and a cooling atmosphere behind the high...can lead to large areas of dense fog. This type of fog can be very dense and lead to below mins visibility. The good news, however, is that it should burn off quick...as the skies should be clear above the fog with little layered stratus above.

Warm frontal fog...or fog associated with a low...is typically not as dense...or below mins...but can be persistent all day long.

[Foxcow]

No one mentioned rotor clounds. They hang out on the downwind side of the mountain and are usually bundles of fun.

[the_dmn8tr]

Going along with the Lenticular clouds being dangerous, so are those cumulo-granite clouds. I hear they are very dangerous in Colorado. You get caught in one of those, you are a pile of debris.

[Lee D]

If we are just arguing between which is worse altogether for turbulence, because both will produce a rough ride, I would say the CB cloud wins hands down in terms of shear evil over the towering cumulus. (Get it?. . ."Shear" evil. . . OK, OK that was really dumb.)

As far as lenticular clouds go, if you are actually in one, you would more likely experience up and down drafts. It is the rotors below and downstream of the lenticular that are going to give you the really bad turbulence. Discovered that one the hard way a number of years ago in a single engine Commander over Park City. Thank heavens for turbochargers and the climb rates that go with them.

[bdhill1979]

Originally Posted by Lee D

If we are just arguing between which is worse altogether for turbulence, because both will produce a rough ride, I would say the CB cloud wins hands down in terms of shear evil over the towering cumulus. (Get it?. . ."Shear" evil. . . OK, OK that was really dumb.)

As far as lenticular clouds go, if you are actually in one, you would more likely experience up and down drafts. It is the rotors below and downstream of the lenticular that are going to give you the really bad turbulence. Discovered that one the hard way a number of years ago in a single engine Commander over Park City. Thank heavens for turbochargers and the climb rates that go with them.

PC is a bad area to go in a single on windy days, One instructor I had (the same one that confused the hell out of me about "Towering Cumulonimbus") took me over there from 36U one afternoon to do slow flight in a Katana. Bad idea to say the least, we were lucky. That was one of the reasons I dropped that guy.

[Bandit_Driver]

Originally Posted by Chris_Ford

Standing lenticular for the win!

Very nice...don't forget all the fun you have have with mountain waves and rotors...