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Old Jun 11, 12, 7:26 am
  #91  
 
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Originally Posted by BotB View Post
-Post detailed METAR or TAF (and any other relevant weather) information during periods of weather delays or interruption at an airport BA use in the hope it helps those travelling in their plans
Do we seriously want to waste space reposting TAF/METAR data that is easily and readily available elsewhere without any effort or registration required to gain access to it ?

Second, Meteorology For Pilots by Mike Wickson is the book to buy and read cover-to-cover if you want to understand the hows and whys of meteorology as it affects aviation and how to interpret the various forecast data. (ISBN 1840372842)
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Old Jun 11, 12, 7:48 am
  #92  
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Possibly not, although some readers now have an idea how to decode a TAF/METAR. Fortunately I was trained to be able to do that.

But then we don't really need threads on Clouds, Trip Reports, discussion on champagne in the FLounge, Celebs on BA or advice on where to go on holiday.

What should we be discussing? I'm accused of posting drivel, so I shan't make any suggestions.
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Old Jun 11, 12, 7:58 am
  #93  
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Originally Posted by T8191 View Post
What should we be discussing?
I believe the biggest killer on any forum is the meta discussion. Discussing the validity of a post, poster, topic or even the entire forum is a prayer without an end and should be avoided at all cost. Hence my conviction that the self appointed forum police (not the moderators) are creating more noise than they are preventing.

I do NOT believe Short Final is one of those by the way. I think his question was quite valid. I like clouds but I have no need for decoding the meteo-speak. If I want to understand that, I will buy the suggested book.

Ideally I want to post a picture of the evening sky and ask the experts if I need to bring my garden cushions inside.

Last edited by henkybaby; Jun 11, 12 at 8:06 am
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Old Jun 11, 12, 8:04 am
  #94  
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Originally Posted by henkybaby View Post
I believe the biggest killer on any forum is the meta discussion. Discussing the validity of a post, poster, topic or even the entire forum is a prayer without an end and should be avoided at all cost. Hence my conviction that the self appointed forum police (not the moderators) are creating more noise than they are preventing.

I do NOT believe Short Final is one of those by the way. I think his question was quite valid. I like clouds but I have no need for decoding the meteo-speak. If I want to understand that, I will by the suggested book.

Ideally I want to post a picture of the evening sky and ask the experts if I need to bring my garden cushions inside.
I concur, henky ... and my slightly piquant comment was certainly not aimed at Short Final.

The self-appointed Forum Police are a different matter.

Last edited by T8191; Jun 11, 12 at 8:10 am
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Old Jun 11, 12, 8:05 am
  #95  
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Originally Posted by T8191 View Post
I concur, HIDDY ...
Quick! Change it before the mad expat finds out you think I am he!

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Old Jun 11, 12, 8:09 am
  #96  
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Originally Posted by henkybaby View Post
No, no heavy aftereffects.
Your photos are great henk but they always have a strange feel. Do you use an HD effect on them? It might just be the border which I think is ghastly.
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Old Jun 11, 12, 8:11 am
  #97  
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Originally Posted by HIDDY View Post
Your photos are great henk but they always have a strange feel. Do you use an HD effect on them? It might just be the border which I think is ghastly.
They are shot on an iPhone with Pro HDR indeed. The edge is getting really old, really fast, I do admit. They work better on the black background on which they are normally used.

The 'strange feel' is what I am aiming for by the way.
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Old Jun 11, 12, 8:11 am
  #98  
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Originally Posted by HIDDY View Post
Your photos are great henk but they always have a strange feel. Do you use an HD effect on them? It might just be the border which I think is ghastly.
Broadly agree ... they would nice framed on a wall, but somehow the effect is too distorted.

Last edited by T8191; Jun 11, 12 at 8:17 am
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Old Jun 11, 12, 8:54 am
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Originally Posted by T8191 View Post
Possibly not, although some readers now have an idea how to decode a TAF/METAR. Fortunately I was trained to be able to do that.
I was trained in that too.

However, there are many websites out there that will decode them for you (at least in a manner good enough for a non-pilot). So my point still stands.

Reminds me of a certain other forum I lurk on where if there's an incident, you're guaranteed to get some armchair investigator posting a TAF/METAR even if the weather is CAVOK with a mild breeze. Grrr.....

Originally Posted by T8191 View Post
But then we don't really need threads on Clouds, Trip Reports, discussion on champagne in the FLounge, Celebs on BA or advice on where to go on holiday.
Indeed.

Originally Posted by T8191 View Post
What should we be discussing? I'm accused of posting drivel, so I shan't make any suggestions.
The state of BA and its fleet, its place in the current marketplace. New routes. Useful tips & advice. All sorts... but anything other than the stuff you listed above.
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Old Jun 11, 12, 9:02 am
  #100  
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Originally Posted by Short Final View Post
The state of BA and its fleet, its place in the current marketplace. New routes. Useful tips & advice. All sorts... but anything other than the stuff you listed above.
With you up to that point!

But from there on, is that really what FT is about? I thought it was Miles and Points? As to new BA routes, that's pure conjecture, isn't it?

Tips and advice ... Yes! But not apparently from Silvers and below, or those who fly less that n times a month

Fly safe
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Old Jun 15, 12, 11:09 am
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From my TR,

This one is in east London somewhere around 9:45pm, I guess it is a broken nimbostratus and bits of altrostratus higher up maybe?




Just starting approach to Singapore around 4pm, some hazy clouds and cumulus maturing?

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Old Jun 15, 12, 1:31 pm
  #102  
 
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Originally Posted by T8191 View Post
Possibly not, although some readers now have an idea how to decode a TAF/METAR. Fortunately I was trained to be able to do that.
I have no idea, I was not trained to do that, but its quite interesting to learn something new about the clouds one spends so long looking at

Originally Posted by T8191 View Post
But then we don't really need threads on Clouds, Trip Reports, discussion on champagne in the FLounge, Celebs on BA or advice on where to go on holiday.
Yes we do!

Originally Posted by T8191 View Post
What should we be discussing? I'm accused of posting drivel, so I shan't make any suggestions.
Anything and everything that is remotely relevant to travel on BA.
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Old Jun 15, 12, 6:03 pm
  #103  
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Sorry, been negligent in my duties...hadn't noticed the new posts as I've been busy doing the day job...

Down to it:

Originally Posted by angeloedades View Post
It has been raining for 2 days non-stop now here in the Sydney CBD and I thought these were mean-looking clouds!





/AE
The first picture is of some Stratus that has formed below the base of the cloud that is providing the precipitation, the stratus appears quite well defined so the air below the main cloud deck is not as saturated although with time this will change if it continues and the two clouds can start to form together and join...

The second one is interesting but I can't tell what type unfortunately...nice picture though! Can you provide any details of the weather during this time? Was there a warm front passing through? Is this photo very recent (last day or so? If so I can try to look at some satellite photos and come back on this...)

Thanks for posting! Hope the trip is going well...

Originally Posted by Moomba View Post
It has been raining for two years non stop in London.
Certainly feels like, doesn't it

Although we can use the moisture back in the UK soil, it would be better if it was more continuous and drizzle rather than convective showers.

Right now we are getting one system after another coming straight at us from across the Atlantic in what is known as zonal weather rather than meridional weather pattern...this is due to the fact that the typical Azores High has not built in as strong as it used to and therefore systems do not get weakened before they hit the UK and they do not have to travel up and over and then back down to the UK after weakening over colder water / land and losing energy...afraid it will be more of the same until we get a good blocking high pressure system in place...

Originally Posted by henkybaby View Post
It is kind of nice here. No, no heavy aftereffects.

Nice photo HB , some Altocumulus that has flattened and is becoming Altostratus as the vertical energy goes out of the air mass...see comment below about bringing the cushions in...

Originally Posted by Short Final View Post
Do we seriously want to waste space reposting TAF/METAR data that is easily and readily available elsewhere without any effort or registration required to gain access to it ?

Second, Meteorology For Pilots by Mike Wickson is the book to buy and read cover-to-cover if you want to understand the hows and whys of meteorology as it affects aviation and how to interpret the various forecast data. (ISBN 1840372842)
Good to hear a different opinion and viewpoint. Thanks for looking at the thread. I do hope that I am not just repeating a METAR or TAF without any further value...What I hope I have brought to the mix is some insight into why the TAF is calling for that weather and how the finer details of the TAF or METAR can help to interpret the situation (where it is causing a BA delay or issue)...see my posts up thread about the Jersey or Gatwick fog for example...I find a lot of the automated conversions for METAR or TAF fail at the important details and obviously don't give insight...Maybe this will change your mind about the value of them here...but I am happy to go with what others find of value and drop what they do not...please do remember that many reading the thread are not pilots or ATC controllers, etc...and may find the odd occasion of some info of interest and use. Hope this makes this thread more interesting.

Personally, any source, be it a book, website, video, etc...providing information that is useful to a person is good, so I am glad that you found that book of particular use. I am not familiar with it and will definitely have a look.

Originally Posted by henkybaby View Post
<snip>...
Ideally I want to post a picture of the evening sky and ask the experts if I need to bring my garden cushions inside.
In the case of the above photo...No, you can leave the cushions outside

Originally Posted by Short Final View Post
However, there are many websites out there that will decode them for you (at least in a manner good enough for a non-pilot). So my point still stands.

Reminds me of a certain other forum I lurk on where if there's an incident, you're guaranteed to get some armchair investigator posting a TAF/METAR even if the weather is CAVOK with a mild breeze. Grrr.....

Indeed.

The state of BA and its fleet, its place in the current marketplace. New routes. Useful tips & advice. All sorts... but anything other than the stuff you listed above.
Hope my above elaboration of why the TAF and METAR along with extra info may be of interest and use, however, as mentioned, if people don't find this of interest...I'll happily stop!

I'm a firm believer in trying to generate interest and foster knowledge...So if someone takes an interest in a weather event and asks I hope I can be of help.

I do believe the weather affects travelling and some BA operations here in the UK as well as enroute / outstations and for those interested in the best IFE going...I hope to help them tune into that channel and get more out of it

At the end of the day, appreciate the feedback on this thread. We may have to agree to disagree...

Originally Posted by T8191 View Post
Tips and advice ... Yes! But not apparently from Silvers and below, or those who fly less that n times a month
I disagree...Maybe the forum has a 'feeling' about it that stops Blue/Bronze/Silver people from posting about what they find of interest...but I do not see any guideline stating that they cannot post their thoughts and trip reports in World Traveller...I just think most posts are from those people that are willing to put finger to keyboard and express themselves...I hope we get a balance and have the spectrum available on here...I am sure things will swing back to 'normal' from the current F overdose...

Originally Posted by Stez View Post
From my TR,

This one is in east London somewhere around 9:45pm, I guess it is a broken nimbostratus and bits of altrostratus higher up maybe?




Just starting approach to Singapore around 4pm, some hazy clouds and cumulus maturing?

Full marks for the first picture Altostratus call...however, the lower layer is Stratus that is turning into Stratocumulus, this lower layer is not very thick and you can see the 'rolls' (undulates) and ground between the breaks in the cloud...if it was Nimbostratus, you wouldn't and the Nimbostratus would extend from that lower layer all the way up to 10,000 feet or far higher... (think of Nimbostratus as a cube of fog that extends one or several Km in all directions...instead of a cloud that looks like a sausage like these ones do...) Good guesses though...you have the right 'type' of cloud, formed in stable air conditions...

The second photo is harder but a great photo

I believe we are seeing some ACC (or Altocumulus Castellanus) which is mid level turbulent clouds and some lower level Cumulus as well...the reduced visibility I believe is due to a large presence of particles for saturated air to 'wrap' around and start to form cloud...the conditions appear correct to form cloud but for some reason the cloud does not build uniformly in this photo...you see reductions to visibility because the light is being scattered away by these particles and does not reach your eye...in any case the 'haze' here is saturated conditions and plenty of CCN (Cloud Condensation Nuclei) allowing the start of cloud formation which reduces the visibility but as the conditions do not allow cloud growth everywhere we see some ACC forming in some places and only 'haze' in others...I expect that there is/was a high pressure that has been over the region for a few days or weeks and with all the particles in the air not being transported away and simply get trapped in this mid to upper levels until a new air mass comes in and 'cleans' the air out...There is some very good detail of the lower 'fibrous' cloud that develops into ACC as it hits a pocket of upward vertical potential and creates the well known bumpy cauliflower type heads (hence the castellanus term)...You can see this in the cloud in the middle of the picture on the left side (at the same position as the outer engine but on the left edge...where the cloud is darker and shears away, almost like a iceberg but in reverse...quite typical of ACC cloud...a clearer, less polluted photo of what you have here is:

Example of ACC developing

Originally Posted by Aloxford View Post
I have no idea, I was not trained to do that, but its quite interesting to learn something new about the clouds one spends so long looking at

Yes we do!

Anything and everything that is remotely relevant to travel on BA.
Agree, and glad that you find this of interest.

Sorry for the incredibly long post, hope the explanations are of interest.

Last edited by BotB; Jun 16, 12 at 2:34 am Reason: add detail and correct some grammar
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Old Jun 16, 12, 4:08 am
  #104  
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Lesson 3: Air Masses


The World is a Bunch of Bubbles by kind permission of NOAA, on Flickr

So, from previous posts we now know that we have weather because of temperature variations and the movement of that air to try to balance out the temperature which causes wind and modification of that parcel of air, causing cloud, precipitation, sunny weather, etc…we also know a bit more about the various clouds and if they are stable or unstable…but an important middle piece is missing…

Why is it that we get stable conditions and weather in some locations and unstable conditions in other areas…for example…the UK tended to get fairly moderate weather conditions year round whereas say in Florida you can get Hurricanes!…why? Shouldn't we just be one big air pocket that is colder at the top and warmer at the bottom and continuously mixing?

In a simplified world the answer is no. Although we have one atmosphere and of course all of this is mixing, we define the weather an area is experiencing by the air mass that happens to be over it at the time or by the weather that is between two air masses with different characteristics.

Starting with the UK, we are on an island and in a bit higher latitude…so our weather is typically quite moist (as we are surrounded by Ocean and have lots of moisture available…and the temperature is moderate…not too hot but not too cold either…this type of air mass (stereotyping now) is a 'm' for maritime, denoting the high moisture, and 'P' for Polar, again denoting the temperature, put together they give us the moisture and temperature characteristics of that air mass…so 'mP' means that the air typically is quite moist and moderate in temperature.

An air mass that we are talking about here is a large scale phenomenon…typically several hundred miles across and all the air in that 'bubble' has the same characteristics…so an air mass moving across the Atlantic towards the UK and Ireland will be uniform in moisture (as it is over the Ocean and is not being modified) and generally in temperature (if it is not moving North or South as well but rather mostly just at the same latitude…

This large mass of air defines the 'ability' of that air to produce weather and develop…as you can imagine…if the air is very warm and very moist…it can develop into much more dangerous weather than a cold and dry air mass (as there is little temperature difference between the bottom and top and little moisture for it to form cloud or precipitation…

A chap named Bergeron came up with a general air mass classification that we still use today (slightly modified) and helps us to understand what potential the air that is moving towards us is capable of and what weather will be associated with the transition zone between two air masses…

So, what do the letters stand for and why are they important: (using the first image above that is in the public domain and kindly provided by NOAA)

m = maritime (read moisture laden)
c = continental (read dry as over land so less moisture)

second letter describes temperature:

A = Arctic (or cold!)
P = Polar (or moderate temperatures)
T = Tropical (hot)
E = Equatorial (very hot)

There are others but these are the main culprits…

In addition: there are now a few other factors added to these descriptors...such as the stability of the airmass and (if known) how it is developing...Stable or Unstable are self explanatory...essentially giving some idea if this will develop Cumuloform cloud / Thunderstorms or not...(see the wiki article below for more info on this as well as identifiers for what attributes the air mass is taking on and modifying to...)

You can see an air mass called cA over the Arctic of North America and Greenland in the diagram…this air would be quite cold and have very little moisture…as cold air cannot hold much moisture, so typically would be very stable air and have very little 'weather' associated with it…this is why you do not generally get thunderstorms in the Arctic…and typically also get less turbulence over such regions (unless they are jet stream induced)…

Over the Equator, you see an mT air mass…this is a hot, very moist air mass that can produce strong thunderstorms, hail, turbulence, flooding, etc…as the only limitations are the air mass itself…it is not limited in growth by the amount of moisture available, nor by the temperature stopping the amount of moisture that it can hold…

Now, if the air was stationary this would be easy…we would know what weather to expect in each air mass…but as the air is constantly moving…the air masses change as they move over new ground…if the warm moist air mass moves over a cold winter landscape in continental Europe for example…it would cool down and lose its source of moisture (the Ocean) so would modify to become a cP air mass eventually…

On top of this situation, we have the transition zones between air masses…this relatively strong change over a short horizontal distance (around 1 to 10 miles wide) is the area where cold and warm air clash…and are what we call a 'weather front'….a cold front is the transition area where a cold air mass is advancing….a warm front is where a cold air mass is retreating…(for some reason we decided to always describe what the cold air is doing!)

two examples of air masses are below…(the 'bubble' of air over a flat ground surface being looked at from the side instead of from above as shown with the main NOAA image above)


mP air mass, 8 Km high by BA_pics, on Flickr

Here is a maritime Polar air mass (moderate in height, representing temperature potential and showing a cold front on the right hand side with a warm front on the left hand side)…guess what my next lesson will be! Fronts…even if they are not at the front of the queue….

Below is a representation of a mT air mass…much more vertical height to represent the increased temperature difference from hot below to cold up top…and smaller in horizontal size…typically mT weather is more convective...


mT air mass, 16 Km high by BA_pics, on Flickr

Cold fronts tend to be more defined and a much more abrupt transition between the air masses so the weather is also more dramatic…the warm front is more gradual and can be spread over 100 miles in some cases so the weather is more cloud and less showery precipitation…

The air masses tend to follow the wind patterns which in turn are based on temperature convection cycles that dominate at that latitude and also are influenced by the Ocean currents and temperatures of water and land…so depending on the season and surface beneath you, you will experience different patterns…around the UK we see generally a West to East movement and typically little strong deviation from the mP air masses…

However, as we have seen of late…we are starting to see more mT air masses coming to the UK and even some cA air masses in winter…giving us much more varied weather than we are used to…cold, snowy winter periods for several weeks and thunderstorms and heavy convective showery rain in Spring and Autumn…causing no end of frustration for BA as these unexpected changes in weather will affect how much staff they need, fuel to fly, airport movements, even down to how much and what we eat!

There is a good Wikipedia article on air masses here for those that want to explore this in more detail or for a better description of these main drivers of the weather you will receive anywhere…

http://en.wikipedia.org/wiki/Air_mass

Please also see this excellent post from simonrp84 showing a recent satellite image of the air masses EUMETSAT can now derive from the data they collect:

post116

that post shows the large scale the air masses cover and the variation of the air mass distribution around the world

Hope this helps you to understand the weather a bit better and also to try to identify the clouds you see and look for fronts when you are flying next time on BA!

Let me know if I have made a right pigs ear of this or if anyone has any questions...

Last edited by BotB; Jun 17, 12 at 1:39 pm Reason: mistakes...and adding link to EUMETSAT air mass product
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Old Jun 16, 12, 11:36 am
  #105  
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You are doing an extraordinary job in informing us. I really do applaud that, most sincerely.
I doubt it would happen on the VS Forum

So, let me pose you a question. Not UK related, but around DC.

The forecasts in DC for Spring and Fall often/always flag up thunderstorms, usually in the afternoon. Sometimes they don't happen, sometimes they do … and they're very wet when it happens! Usually with an easterly flow as well, which I would have thought would have dumped any moisture through orographic lift as it crossed the Allegheny's.

To what extent, in your view, is this created by the vast expanses of tarmac/concrete generating thermal lift?
Put it another way … do big cities cause rain?
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