How do CLOUDS and THERMALS really work?

[@FlyWithGreg]

NOTE the graph Y axis should read km (kilometres) not m (metres)

[@BrianStewart-r6u]

A small point, but collisions between molecules don't create any energy, they just distribute it to other molecules. The temperature reduction is caused by the work being done in expanding the bubble of air, thus reducing the kinetic energy of the molecules and lowering the temperature. Your conclusions are spot on as always, just a minor point on the physics. Keep them coming, you do an awesome job for paragliding, best explanations of the lines on tephigrams I've seen.

[@IDNeon357]

Greg, thank you for this; you should market this to firefighters in the US because we honestly rely a lot on how these weather mechanics work because in the mountains here the fires live in the thermals as you've described them. Fire will hide and spend the night in the inversion layers along the mountains. Knowing how cloud build-up works matters because its the Thunderstorms that cause fires. And the fires cause their own storms. Growing up where I did it's generally dry. But when fire fighting I was rained on virtually every day. It's a microclimate and it's intricately linked to your super simple way of explaining how the air parcels all work.

[@williamparker3192]

greg, i am truly loving absorbing all this knowledge. thank you for your hard work

[@waylingtons]

Greg, you explain things so well. Some of the best flying content and knowledge sharing there is. 👍

[@skypiratez]

25 years of paragliding and some awesome long distance XC flights under my belt and still learned something new from this video... Thanks Greg!

[@glideasia2313]

Hi Greg, I shared your video with the Thai pilot community here. Nearly all of them asked me to translate it into Thai. I have done a community translation on here and submitted it for review. I have no idea what happens now but you may get notification....fingers crossed. Another great video...keep them coming. :-)

[@MrKbtor2]

When I was in China everyone watched Greg and asked me to translate

[@brinjal1371]

Hi @glideasia2313

[@jschall12]

This is gaseous thermodynamics with Greg!

[@lennyoliveira9178]

I did paragliding as a hobbie once in Cape Town with my sister while she was on her holiday. It's been a while. I'm searching now, and eventually, I find it out. Such great content. I'm working on myself to get back to it again, but as a regular hobbie. I would like to hit it every time the weather cool nd I want to learn as a professional do. Thanks for sharing GREAT CONTENT 👍 Love from ÁFRICA 🇦🇴♥️ ANGOLA

[@Robbo1966]

A super clear and concise description of thermals and cumulus.

[@guilhermeschweitzer8459]

Best explanation I've heard about thermals so far Thank you!!!!

[@edwardbowora]

The best explanation of skew-t i've heard after numerous searching.

[@yaquot]

Fantastic video with great theoric about thermal, a big thanks.

[@jeffspicoli2643]

This is so fascinating to me. If I ever fly close to the clouds base... I will think of you immediately. I love listening to you talk and I'll have to watch this again. Thanks!

[@mikecolley-]

Best Cloud explanation and easiest to understand I have seen so far. I like it. Thanks Greg!

[@evanbarnes9984]

Well that's the clearest explanation I've ever heard of that!

[@cloudwalk66]

Thanks for the lapse rate for dummies bit. Although I have needed to know how to calculate them in the past I’m not sure that I ever had a clear understanding. By simplifying it, you have made it easier for me next time.👍

[@thegardenfarmer]

Man Greg, your videos are always great!! They are packed with extremely understandable knowledge and wisdom. You make sure to be so thorough and just want to say it's much appreciated!! I watch "ParaglidingTalk" by @robert michaels and I have always mentioned during the show that you should be a guest. It would be super amazing to have you on that show and chat with some amazing people. The tough part would be timing... the show airs every Thursday, 6pm PST. Now if Im not mistaken... I believe that would make it ... 2am your time. :) Gonna head to the website and browse at some more knowledge.

[@513eis]

That was a very good explanation of thermals and cloud formation. You put it all together for me. Thank you.

[@FlyWithGreg]

Glad you enjoyed it! Now go find some thermals (hint: good lapse rate)

[@aaronjeancrombe4754]

Thank you so much Greg for those videos and your generous sharing of knowledge. It's hard work to put all that together but so truly helpful!

[@JohnnyFaber]

Best paragliding videos ever Greg. Always love your content. You have a very calm demeanor and you explain things very thoroughly but in terms that make it easy to grasp and retain. Educational and relaxing, great combo!

[@FlyWithGreg]

Thanks Johnny, I enjoy sharing my knowledge with the few people my skills are relevant to. What's that, almost 10,000 subscribers? Flapping heck, I better make another video then :-)

[@bigandy1982]

This video is gold. Thanks for explaining it so well.

[@christianmenzel5674]

Thank you for sharing your knowledge with us

[@AddictionHappiness]

Its always great to hear things like that!! 🙏🤙💯

[@Robbo1966]

Really great explanation, of a complex subject, thanks Greg

[@lessainsbury8508]

Hi Greg although I am not a paraglider pilot ( I did fly a paraglider a few times on the training hill ) my background in aviation is in hang gliders, sailpanes and fixed wing aircraft. I have seen a few of your videos now and I have to commend you on your presentaion. Absoulute understandable ,quality videos . I do have to take issue one one point in this video at 8:33 where you said that there needs to be an inversion to stop the cloud from rising further. While this is true ,the presence of a stable layer ( very little ,or no change in temperature with altitude) will effectivly do the same thing,although it won't arrest it as fast as an inversion will. Many instructors will say that thermals are stopped by an inversion layer when actually they are being stopped more often by just a stable layer. Keep up your great content.Your efforts are appreciated by many.

[@lessainsbury8508]

My bad Greg . I did not see on the graph at 8:56 ,where you wrote " Or at least a stable lapse rate " Once again Kudos for an explanation that anyone can understand.

[@alasdair1571]

Great explanation...one to watch again

[@whattodo9001]

I'm sooooo happy I've found this channel not so long ago ^_^ Thank yoy for sharing your experience in a very easy to understand way.

[@vsabadazh]

Interesting and clarifying explanation. Thank you Greg!

[@hrfb9696]

Thank you for sharing such an important basic knowledge. Be safe Thanks

[@luizrobertoosoriobaum815]

Thank you, Greg!!! Great video!!!

[@niklas7355]

Thank you so much for sharing youre knowledge about thermals. Ive been searching a Video explain also this graph from windy, cheers mate, I wish you good flights 🦅

[@malcross2524]

Excellent tutorial Thank you

[@christophostrowski3382]

Einhunderttausend likes für Deine Videos! Greg, Du bist echt Inspiration

[@Gjoa1906]

Excellent overview - well explained. Many thanks.

[@CuivTheLazyGeek]

I loved the general explanation! But it feels like the chart explanation was lacking - I found those graphs exceedingly hard to wrap my head around when I started studying them (one of my questions was: the dew point curve is always to the left of the rest, why does it even condense??) and I feel that how to read an interpret the graph should be the subject of a video in and of itself. Love the channel!

[@ShobhitGupta12]

Yeah, would love more detailed explanations. I don't understand how that blue dotted line came to be. Why is it inclined at a certain angle and all that.

[@FlyWithGreg]

this can get complicated and very detailed so I've kept it focused only on the basics here, on the cloud engine itself. Find a skew-T sounding for your own flying site / area and play around with it, you'll learn fast. The dew point curve sometimes touches the red temperature trace, then you get a static layer of cloud (100% humidity, no convection).

[@CuivTheLazyGeek]

@@FlyWithGreg Completely agree, and again that explanation was awesome. Thank you as always!

[@niconico3907]

The chart is wrong, if the dew point is left of everything it doesnt condense.

[@HermannLoose]

@@niconico3907 The way I remember learning it: the dew point curve gives the temperature at which condensation would occur for air that starts out at the same altitude, given the relative humidity at that altitude; this is what the balloon measures as it is going up. However your thermal air bubble starts at the ground. It will condense at roughly the dew point temperature measured at the ground. This is the dotted line that Greg traced at 4:54 (it's not vertical because air density and relative humidity varies with altitude)-when your adiabatic line from ground air temperature (orange dotted line) intersects it, that's where that air bubble will start to form a cloud. Red (continuous) line touching blue (continuous) line: air starting out *at that altitude* will immediately condense = 100% cloud cover. Red line quite far from blue line (= very dry air throughout): you get "blue thermals" lifting you up but no cumulus clouds to be seen.

[@jameswestgate416]

This is a lot like being back in school with you Greg!

[@PPGATL]

Hi Greg Liked and new subscriber. I'm a paramotor pilot who tends to be a bit geeky and I really appreciated this video. I have been using and preaching the Skew-T charts to all my PPG buddies who would listen (most don't) and I've wondered how interesting they are for PG flights. Now I know. The charts have a long learning curve but they provide so much information that I'm astounded that more people with and without motors don't use them. I understood some things about them already but you've added to my knowledge and understanding of the cloud engine with this video. I plan to eventually be a daytime motor off thermaler (no hills to launch from in this area) and this will certainly help. BTW, there is a Skew-T app on Android which seems to work fairly well. I rely on it more than on any other weather app for day of and day prior to any flying. Thanks!

[@KilkennyLights]

Greg, you explanation was just perfect. A video on how to deal with the white room and how to stay calm would be good. As a new pilot I was sucked in for over forty minutes. It was the most scared I have ever been paragliding. Its also very lonely inside a dark cloud. My instruments were of little use as I was so busy keeping the glider inflated. My two euro compass saved me and I kept flying east until I was close to the sea side and the Sea breeze cleared the clouds. I landed beside a church and kissed the ground as I was so grateful to be standing on it. I have made so many mistakes over the years including a river landing in Spain as the valley winds had me flying backwards. I could go on and on. I think if you had a video on beginner mistakes and how to deal with fear when things go horribly wrong when you only have two hours experience. I had my first full stall at this stage which lasted four seconds. It was beyond terrifying. ! The good thing is that was fourteen years ago and I love flying more and more each year. Well done Greg for all the good work you do for the sport. Many thanks. Frank Manning.

[@FlyWithGreg]

Thanks Frank. Keep Calm And Carry On is a hard mindset to find in the face of terror, but it always leads you to the safest outcome. 40 minutes in whiteout is extremely frightening, no doubt. I'm glad you had that little compass!

[@flyblueskyguy5863]

Scientific and super interesting. As a current PPG pilot, I am looking forward to one day experience the skill of a PG pilot. Great video. Thank you Greg.

[@niconico3907]

Good luck, understanding and using the thermals is much more rewarding than pressing your throttle.

[@alaindion2326]

Merci Greg! Solid explanations!

[@CalebJohnsonlivingca]

Wow... I think I need to get that course and fly with Greg.

[@ShobhitGupta12]

Oh hey Caleb! Small world.

[@nigelholder5514]

Thank you Greg for explaining something I knew a little bit about; but in a way that has clarified it perfectly. Weather to Fly! I’ve just subscribed!

[@htamerursavas]

Excellent video. That cannt be explained better by a video. Just one thing though Most of the time the thing that stops the clouds to overgrowth is wind aloft. Up there if the wind blows 40km/h, that cloud can not get higher but under that cloud there could be a strong lift. So most if the time wind demolishes or tears towering clouds. This video i think is the best instruction you shoot. I can feel how much effort and thought you spend in this video.

[@FlyWithGreg]

If there's a good lapse rate the cloud will continue into wind aloft, it just gets tilted, but yes I get your point, wind can shred clouds

[@jessesavoie6029]

Very well explained. Thanks keep it up

[@flynaren1]

Beautifully explained,Greg ! This is superb educational video....Great value !

[@timothycurran8474]

Great explanation thanks Greg!

[@MichaelWong-q7k]

Thanks!

[@brucekendall52]

Super interesting,thanks.

[@richardfleming8486]

Nice info. Thank you 👍🇿🇦

[@voolivrepipa]

Great video! Thanks

[@removechan10298]

really cool video!! thanks!

[@climb315]

Thank you wery much!

[@andersborum9267]

I always wondered about the mechanism of the backside of cumulus clouds; you've answered a number of questions I was prepping on asking during training next spring. Are there many incidents with PG pilots being caught on the backside of these thermals (i.e. popping through the cumulus unable to escape)?

[@FlyWithGreg]

No its very rare, it is so easy to fly out of a thermal, and so hard (in the beginning) to stay IN them!

[@mbrunnme]

kzbin.info/www/bejne/inbTfIGilptmgdk

[@5ty717]

Excellent…

[@damdammah406]

This video is particularly good. thank you..

[@overunderabove]

Really helpful - thanks, Greg

[@carts4138]

Awesome explanation...

[@albertobarpao]

Great content!! 👏

[@redbullx-alps]

Great video!

[@gabiciaba]

Greg, if you are gonna write a book about flying, i would definetly buy it!

[@Naturalmedicineprescription]

Class mate ,wow so much to learn :D

[@Andyg2g]

Hey Greg, awesome video! Thanks for the content! If I may ask, what weather/wind/cloud forecasting app do you use? I've been looking for an app that paints a more robust image of the sky for my local flying area (Point of the Mountain, Utah), but everything I've tried so far seems to fall a bit short. Thanks in advance!

[@FlyWithGreg]

Try a search for RASP Dr Jack, or use xcskies. Windy.com right click you can get Soundings but they don't seem quite as accurate as RASP. I go into much more detail in my weather series on flywithgreg.com

[@crimsonraen]

Hmmm, being spit out as a cold, hypoxic block.. Yeah, no thanks. ;) Thanks for the video, Greg!

[@Amac-uz9hm]

Great video Greg, be safe👌

[@FlyWithGreg]

Thanks, you too!

[@flyskiride]

brilliant video thank you

[@IvoBELGIUM]

this is great, thank you

[@lucianosantucci108]

Cheers

[@niconico3907]

Hi Greg, great video. I think your dew point line is wrong on the drawing because your thermal temperature line doesnt cross the dew line, so the cloud doesnt form. For the cloud to form and climb up, the thermal temperature has to be left of dew point ( otherwise it doesnt condensate) and right of environmental temperature line.( otherwise it doesnt climb).

[@bryantuffnell3387]

Not so, but a very understandable mistake. The thermal moisture content is derived from the source, at the surface.whee the thermal was born, not the surrounding environmental air at altitude. Therefore the dew point trace is irrelevant for a rising parcel of air. The moisture content of the thermal is constant, and we follow up the line of constant humidity, not the dew point temperature trace, to find cloud base. It’s a different line on the graph, which Greg didn’t cover. :)

[@musicforlife4571]

Another great video Greg, thank you! (one little note, you have a typo on your graph, the vertical axis shows an altitude scale of 0 to 4 meters) 😜

[@Gin_FireFly]

Great video! I was wondering for a while how come clouds work the way they do. Please allow me to express doubt about what you are saying at 2:45. If you take ideal gas law, you will see that with increasing volume (of the air in the balloon) the PRESSURE will go down but not TEMPERATURE (in a closed system which it is). This mistake can be easily made if you consider temperature as number collisions. However, the temperature is the amount of kinetic energy the gas has (which of coarse increases the number of collisions but it is still a consequence, not a cause). It doesn't influence your further arguments so it's just a detail. I don't know how these balloons work but I guess they measure the difference in pressure inside the balloon instead of temperature. Or I made a mistake somewhere? If I did, please correct me. Still, thank you for making this video! I learned a lot!

[@mcsons13]

Look up isentropic expansion: Reducing the pressure through an adiabtic will indeed decrease the temperature and increase the volume.

[@pani8685]

Muy buena la traducción para aprovechar los castellanos parlantes

[@i_msud2088]

Hi greg thanks for this beautiful lessens i saw your wbsite and tryed to saw some video but i needed to pay for it but unfortunately i cant effort it .i wish i could saw them and increase my knowledge😑😔💙

[@heinrichstander1838]

great vid

[@andres-vi1uy]

I don't really understand the dew-point, (to me it looks like the temperature is always above the dew point) how do you read that on the graph?

[@notafanatic]

did anyone else notice the guy at 6:20 still going up with big ears...

[@FlyWithGreg]

Beginners luck. You know if we followed him we'd go down like a ton of bricks ;-)

[@SilverSniper75]

Ha. Only noticed it now that you said it 😆

[@AndresFly]

Hola Gerg !¿ en tu sitio web los videos están doblados o subtitulados al español?

[@FlyWithGreg]

La mayoría de las lecciones están subtituladas en español

[@ladduro]

isn't SALR cooling in average at 0,65C/100m ?

[@rrrrrrrrrrrrrrrrrrrrr]

Is there a "x1000" missing from the vertical axis of your charts?

[@FlyWithGreg]

Yes but it's impossible to add it now, so I hope most pilots will figure that little puzzle out ... km not m!

[@ericfisher9206]

Maybe I’m misunderstanding you but I don’t think what you are saying at 2:20 in the video is correct. This is the way I see the world working. Cold air is dense and the molecules are tightly packed together. Hot air is less dense because the molecules are moving and create space in between. A hot air balloon goes up because the air is less dense and lighter. A balloon gets bigger the higher you go because of the pressure from the atmosphere the same way it would get smaller as you submerge it deeper in water.

[@Gin_FireFly]

I think similarly, I commented with a more detailed explanation higher up.

[@krijo210]

The Ideal Gas Law states that PV=nRT. If you heat a gas (T increases) but keep the volume and pressure constant (like a hot air balloon), then 'n' (the amount of air molecules) have to decrease. The heated gas gets less dense, when air molecules escape from the bottom opening of the balloon. For a rising thermal both the pressure and the temperature of the surrounding air sinks, which the thermal tries to align itself to. So if P decreases, then also T decreases. If the pressure has been equalized, but T is still larger than the surrounding air, then 'n' has to be lower. The thermal is still lighter than the surrounding air and keeps rising. This goes on until the pressure and temperature of the thermal equals the surrounding air.

[@Gin_FireFly]

@@krijo210 thank you for your input! the statements are not wrong in general but are not applicable to the question raised. First, of all you are talking about an open system, we are talking about a closed system. Secondly, Greg clearly describes the expansion of the balloon at 2:30 which suggests that volume is not constant, thus your first statement is not applicable to the situation.

[@bentownsend4017]

Is this copyright free tame impala?

[@migupl]

18k ft is 5.4km. It's not thaat bad - you still have a reasonably long time of useful consciousness. 11km, now that would be really bad (and totally achievable in a CB)

[@dominicsutcliffe5800]

Great video, as always :) Super informative! How do mountains affect the skew-t-chart? I fly in the alps and often find clouds forming much lower than the predicted cloud base from the emagram (skew-t-chart) or expect clouds to build much higher and they don't. Perhaps I'm just reading it wrong...? Example skew-t: www.meteoswiss.admin.ch/home/measurement-and-forecasting-systems/atmosphere/radio-soundings.html

[@FlyWithGreg]

Mountains complicate the picture, because after rains they hold sources of moisture up at higher altitude, so introduce moisture that will condense earlier than you were expecting. After a day or two, on open slopes, the mountain has drained and dried and then it acts to boost the thermal power and the added heat can raise local cloudbases. So it depends on the timing relative to rains.

[@matiascorvinus1769]

isn't 18000 feet almost the same as 5km? 9:42 to 10

[@FlyWithGreg]

Yes, i meant a bit higher ... although even a little bit above 5km is starting to get extreme