Clouds

[dutchroll]

:yikes:That is crazy.

 

:yikes:It looks as if you really need to keep a respectable minimum distance from Cumulus or Cumulonimbus clouds! I wonder what the minimum safe distance is?

I hate to tell you this, but in a big jet (in this particular case the A330), the official recommendation is to avoid all yellow, red or magenta cells by at least 20nm. Given that red and magenta are distinctive CB cells, and yellow is generally lesser CB or towering Cu, I think you can get the drift as to how serious the big boys treat it. Multiply this by an appropriate factor for a GA or RA aircraft! And be aware that you don't need to actually be in it to be caught in the associated windshear.

Really, it's going to screw your day going into even a large Cu cloud in a very small plane.

 

 

[kgwilson]

HG & Glider pilots love CUs. They are what most use to get altitude & go XC (other than wave or ridge lift). The learned knowledge is knowing when to get amongst it & when to avoid. Fair weather cumulous is a joy to be in. Over development & with tops towering & concave bases need to be treated with extreme caution & generally avoided. The lift can be incredibly strong a long way below the base. The vario can be off the scale hundreds of feet from the bottom of a big CB so you have to get out of there quick.... if you can.

 

There are many stories of pilots being sucked up into a towering CU & being spat out the side like a pip that shouldn't have been there or never being seen alive again. These systems demand respect. I had a few scary situations back in my HG days & managed to survive. I was young, felt invincible & stupid. I don't mess with this stuff any more.

 

 

[eightyknots]

HG & Glider pilots love CUs. They are what most use to get altitude & go XC (other than wave or ridge lift). The learned knowledge is knowing when to get amongst it & when to avoid. Fair weather cumulous is a joy to be in. Over development & with tops towering & concave bases need to be treated with extreme caution & generally avoided. The lift can be incredibly strong a long way below the base. The vario can be off the scale hundreds of feet from the bottom of a big CB so you have to get out of there quick.... if you can.There are many stories of pilots being sucked up into a towering CU & being spat out the side like a pip that shouldn't have been there or never being seen alive again. These systems demand respect. I had a few scary situations back in my HG days & managed to survive. I was young, felt invincible & stupid. I don't mess with this stuff any more.

HG? I'm not familiar with that term.

 

 

[Guest Andys@coffs]

Hang Glider

 

 

[eightyknots]

Thanks Andy :-D

 

 

[kaz3g]

You wild old bugga flying that close so your fin was in the hole ... lucky you didn't get sucked right up in that damn thing.I had a mate in a C206 tell me a story way out west flying between centres when he got caught on the fringe of a large CU. He said he will never forget the experience. He said when he realised he was being caught in the up draft he closed the throttle and pointed the 206 down, he said he was right at VNE, throttle closed and still climbing. He doesn't know to this day how he got out of it but said he was absolutely sh!tting himself.

Many years ago I was delighted to find some lift in a Blanik after a which launch on a heavily overcast and building autumn day. My delight turned to something less as I was accelerated vertically upwards near what turned out to be rapidly approaching Nimbus.

 

Dive brakes were out and I had it pointing nearly vertically downwards before it stopped going up. I scared myself more than I think I had ever done before and I was very glad to get back on the ground... Lesson No 1...stay away from anything you can't see through.

 

Years went by and I was on watch in a fire tower on the outskirts of Melbourne. A change and thunderstorms were rapidly approaching. Two wedge tail eagles were happily circling underneath and I remarked on them to my colleague. As we watched they climbed higher and faster. One suddenly folded its wings and headed earthward. The other disappeared into the boiling cloud mass and wasn't seen again... Lesson No 2...never get sucked in.

 

CBs are the repositories of more energy than I ever want to meet in one place, especially when flying.

 

Kaz

 

 

[kaz3g]

:yikes:That is crazy.

 

:yikes:It looks as if you really need to keep a respectable minimum distance from Cumulus or Cumulonimbus clouds! I wonder what the minimum safe distance is?

Glider pilots love Cu's but CB's are something else. Nimbus are also very dangerous...those big, heavy, wet looking buggers that take up a large part of the sky? Stay as far away as possible! Beware of microbursts and very severe turbulence as well as up drafts.

 

Kaz

 

 

[SDQDI]

Just thought I would post a basic cloud identification pic for those who haven't seen one in a while also a nice pic of a rainbow in a lonely little cloud that we found while wasting time waiting for the fog to lift last Saturday so we could go down to scone. (Notice the shadow right in the middle) and also a pic or two of the fog over the other side of the range (from the YQDI side looking to the south) pictures taken with an iPhone hence not A1 quality

 

 

 

 

 

 

[Dafydd Llewellyn]

Most gliders have dive brakes that will limit their airspeed in a steep dive - some even in a vertical dive; 130 knots straight down = 13,000 feet per minute. That will prevent you from being sucked up into most clouds. If you don't have that ability in your aircraft, stay well away from the underside of any active cumulus cloud.

 

 

[cherk]

Really, it's going to screw your day going into even a large Cu cloud in a very small plane.

Just to see hail blasted and dinged aluminium...................http://www.airliners.net/photo/Air-Transat/Lockheed-L-1011-385-1-14-TriStar/0190207/M/

 

 

 

[flyerme]

Jim Davis ppl Book has a complete chapter on met. And he makes it easy to understand!! The books about $110. But well worth it!! Covers everything!

 

 

 

[facthunter]

I'm sure there are more severe examples of hail damage. In a smaller plane it will put you out of the sky. Don't ever go anywhere near it. When it comes to weather I am the original "chickenman". and it has helped over the years

 

Jim Davis book is couched in easy to understand terms. for the new to meteorology people. Nev

 

 

[dutchroll]

I've been struck by lightning at least twice that I can remember even while threading our way through a storm front and avoiding any cells on the radar by 5-10 nautical miles. Although those occasions were in a large multi-engine aircraft, it's still not a pleasant experience, especially when it reaches out and touches you. I've also been on a visual approach into Melbourne with a large cell over 10nm away and gone through its windshear briefly requiring around 80-90% thrust to hold the approach speed (on a B767, which has big beefy engines!). As I was about to hit the TOGA buttons at 500ft we popped right out of it into benign conditions and landed. I'm always at pains to point out to less experienced guys that you don't actually have to be in the cloud to get the effects!

 

 

[SDQDI]

Spent most of the day out of the district thinking about the locals going to scone to watch the Hurricane (plane not weather phenomenon!) and got home to beautiful clouds like this.

 

I haven't talked to any of the boys yet but am assuming that they had to drive down.

 

Clouds like these encourage me to keep the hornet in the shed.

 

 

 

 

[facthunter]

Cumulus Mammatus. Unusual as the clouds sink. While they look impressive I don't think they herald dangerous conditions. Nev

 

 

[SDQDI]

I didn't know what they were called Nev but did a quick bit of Wikipedia research and found these paragraphs. While they themselves are not too bad they were under a serious looking storm clouds.

 

I do enjoy learning about clouds as there is so much info to take in and it seems no matter how many clouds you see you can still learn more and see something new.

 

Mammatus are most often associated with the anvil cloud and also severe thunderstorms. They often extend from the base of a cumulonimbus, but may also be found under altocumulus, altostratus, stratocumulus, and cirrus clouds, as well as volcanic ash clouds.[citation needed] In the United States, sky gazers may be most familiar with the very distinct and more common cumulonimbus mammatus. When occurring in cumulonimbus, mammatus are often indicative of a particularly strong storm or maybe even a tornadic storm. Due to the intensely sheared environment in which mammatus form, aviators are strongly cautioned to avoid cumulonimbus with mammatus. They also attach to the bottom of other clouds.

 

True to their ominous appearance, mammatus clouds are often harbingers of a coming storm or other extreme weather system. Typically composed primarily of ice, they can extend for hundreds of miles in each direction and individual formations can remain visibly static for ten to fifteen minutes at a time. While they may appear foreboding they are merely the messengers - appearing around, before or even after severe weather.

 

 

[Blueadventures]

Cumulus Mammatus. Unusual as the clouds sink. While they look impressive I don't think they herald dangerous conditions. Nev

When those come around Kingaroy. All aircraft go into the hangars and strong winds follow. Usually late September period.

 

 

[dutchroll]

I'd be staying away from them. I don't like clouds which show strong indications of turbulence immediately underneath them like that, even if there doesn't appear to be a huge amount of vertical development.

 

 

[facthunter]

If you observe them carefully you will notice that the movement of the vertical currents in them is not rapid. They are obviously very wet and may obscure other parts of a system . Cb (Cumulo Nimbus) has high rate vertical up currents in it and you don't fly below them, and at high levels in a well developed mature one, the "anvil" shape is often present. Even being 25 miles downwind of such a cloud formation won't guarantee you won't get heavy hail in clear air, and closer is more risky.

 

Cumulus Mammatus doesn't stay long. It tends to lose it's characteristic shape in a short time and form a low altitude "wet" cloud mass. Warm fronts are not too common in Australia, especially in the Southern parts where cold fronts are the main feature of a weather change. America is different in many ways weather -wise

 

The active Cb form in an air mass that has a high adiabatic lapse rate, and a lot of moisture in it to give it the energy and high rate vertical updrafts that promote it's development. Severe turbulence, hail, heavy precipitation and lightning can be expected to occur in and near such clouds. Keep well clear, and go behind them, but be aware of the moisture that will be in the atmosphere after the precipitation that has happened in that area, and you may have low scattered cloud about, reducing visibility.

 

Whether a cloud base is low (affecting OUR ability to fly safely in VFR) depends on the relative humidity of the airmass. A cloud base of less that say 2,000 ft AGL means the RL is probably fairly high (near 100%) at ground level. IF the temp falls a little the base reduces quickly. Nev

 

 

[M61A1]

I am the original "chickenman". Nev

 

 

Probably belongs in the "laughter" section, but I couldn't resist.

 

 

[diesel]

Fohngap clear air between wave.

 

If you can see a cloud you are too close.

 

If you can see a hill you are too close.

 

If you can see the ground you are too close.

 

In the early days you could not fly too close to heaven so sundays were out.

 

My dumb Jodel does not know all this.

 

Chas