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Here is a diagram I drew trying to explain the "Fair weather" winds in the ITW Valley.
Feel free to critique.
Have fun, be careful,
take care,
space

Thanks Spacy. I'm very glad you are sharing your expert knowledge of microweather.

I cannot read the image. It's too blurry.

it look ok here, perhaps your web-browser is shrinking the image to fit it on screen without scrolling?

if you hover over the image you may get an option to switch it back to normal size.

yep, you're right. Thanks!

 
nice work t, but I can't see the bar anywhere..?

Can someone explain why seeing convergence clouds is an obvious sign of the Ora wind..?

My Met. knowledge is a little stretched beyond .."there is a little mist over the landing area..."

I jest ...

but seriously.....would like to know...

I maybe mistaken but I thought convergence clouds are created when dry and moist air meet, I assume that due to the body of water at one side of the range will mean that this is more common at this site? So if convergence clouds are seen this means there is an obvious meeting of air moving up the valley to meet dryer air from the opposite side......

but I maybe talking complete shit of course.....

Nice diagram. Will the Ora blow during the summer under high pressure weather as well ?

I was there last week, we were getting up at 4am to do back to backs, done at 10am, and no more jumping, we did hike one evening but due to winds didn't jump and didn't bother hiking in the evening again...

Convergence clouds are a result of warm air rising to an altitude that the moisture becomes visible due to the cooler and thus less humid air. @ Mac, .
"I maybe mistaken but I thought convergence clouds are created when dry and moist air meet, I assume that due to the body of water at one side of the range will mean that this is more common at this site? So if convergence clouds are seen this means there is an obvious meeting of air moving up the valley to meet dryer air from the.."
The Convergence clouds indicate thermal activity and the air feeding these thermals are the "Ora".
High pressure systems, This is a descending air mass of cooler, denser air. stocking up on millibars to feed the thermics, The Ora is a surface wind, and since ITW is at the south of the Alps the air mass will flow down to the sea creating a flow from the North above the surface Ora winds. In these conditions one must fly in the wind shadow of the wall on the left but still be prepared for the wind direction change at 200m +/- 100m..
take care,
space

Low pressure systems are the crap. This creates an ascending air, sucking in the moisture from the sea, creating a "from southerly" flow causing rain on the rising terrain and very strong winds at the Austrian bridge,(40 - 60mph).
So if there is a low and you have rain at ITW with a "from southerly" flow, you should try chatting up Nadia and Patrizia at the Bar instead of trying the bridge.
Any dynamic wind from right to left on the exit point to 600m below is a no go.
It makes a bowl of turbs that is very difficult to get out of.
take care,
space

Sorry... but all cloud is formed by air rising and the moisture condensing out at altitude.

clicky


Convergence Cloud is formed when the rising air is caused by an air mass hitting something....
(1) A mountain

(2) Another air mass... The result of this collision (convergence) is that the air has to go somewhere - so it goes up.. and it condenses out (as normal) when it reaches the altitude where the temperature reaches the dewpoint.



I often fly (paraglide) convergence cloud in mountain areas, where the local airflow from 2 valleys meet and give me a lift...

Normal (?) thermals are not convergent... they can be seen in flat lands where there is no convergent air flows. They are caused by heating of the ground, which causese the air to warm and rise. If the air contains moisture, then this will condense out



Blues skies and well formed fluffy clouds...

What are you sorry about? Using different words to say the same thing as I?

"Sorry... but all cloud is formed by air rising and the moisture condensing out at altitude. "

"Convergence clouds are a result of warm air rising to an altitude that the moisture becomes visible due to the cooler and thus less humid air"

If you think about it, all thermics are a result of minor convergences. Please explain why clouds hang above the peaks on a fair weather day.
take care,
feedback please
space

Hi,

The reason that I was saying sorry, was that I think that your post implied that Convergence Cloud is the result of ANY warm air rising, when it's actually specifically due to the air being forced up either by hitting a landscape feature or another air mass.

Normal (flatland for example) thermals do not rely on convergence, they are caused by ground heating (like in a Lava Lamp)

Actually the lava lamp is a really good model for non-convergent air movement... and a Stream would be a good model for Convergent flow....

If you look into a stream, you will see the water level changes as the stream flows over pebbles and if 2 water flows meet.

Clouds hang over mountain peaks (on days when the air mass is wet enough) because the air mass is caused to move either by dynamic wind (i.e. it's is windy even in the flat lands, so it's a widespread meteo condition) or thermal induced wind (there may be no Meteo wind, but the local ground heating causes air to be pulled in). The cloud is formed (as normal) when the damp air mass reaches the altitude where the temperature is at the DewPoint (the water condenses).

Further.... even on a cloudless day there cann be thermals and vertical air movement over the mountain peaks-- you just cannt see them because the air is so dry that the moisture does not condense out).... We can still fly on these Blue Days.. it's just more difficult to find the rising air.

The really frustrating days are caused when the air mass is so stable that there is very little thermic activity.... then we sit on the hill and enjoy the view and each others company..... Every [non]Cloud has a silver lining.


.

Keep it in the context from my first post please.
Did you see my attachment from the first post in this thread. Would you say that I am incorrect in stating that “Convergence clouds over the peaks are an obvious sign of the Ora wind”? Would you say that these are not Convergence clouds? If so, then why? The fact is that if these clouds are over the peaks, there will be a honking valley wind.
Me thinks I/you is confusing colliding and converging.
Feedback please
take care,
space

Hi Ya..... we really shouldn't be posting on a saturday morning..... my wife will beat me if I dont get all of my jobs done

Anyway... Maybe I misunderstood... I agree that Clouds over mountains are Convergence clouds due to the air mass converging with the mountain (as from my 1st post) - I just thought that you may be impling that all thermals are caused by convergence.
I also agree that valley winds can/do exist even on non-windy days due to air pulled in along the valleys due to heating in the mountains (the velocity is generally higher, lower to the ground due to the narrowing of the ground features..... as I have bruises to testify!!).

B.T.W : I think that it's great that we're discussing meto here.. I'm not a BASE jumper but a Paraglider pilot but the weather in the mountains affects us much more than the skydivers in general. It's good that were sharing actual experiences.


Thanks for the discussion.

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