Lenticular clouds

[Deej]

Some nice photos on the BBC site of lenticular cloud formations over W. Yorkshire:

http://www.bbc.co.uk/news/uk-england-leeds-16302606

Dave.

 

[starfire]

Saw them today, stunning sight.

 

[johnalison]

Mentioned the Cloudspotters' Guide. More info on their site:

http://cloudappreciationsociety.org/find-a-cloud/#p=1&i=0

Lenticularis is listed on the right along with more clouds than you are likely to have heard of.

 

[LadyInBed]

And here http://vortex.plymouth.edu/clouds.html/

 

[dylanwinter]

big cloud

I saw this weird one over the blackwater

http://www.keepturningleft.co.uk/the-journey/scuttlebutt-38-one-big-cloud/

no idea what it is called

D

 

[grumpy_o_g]

Dunno why the BBC thinks they're rare - perhaps slightly further west than usual but that area's probably the best in England for wave. It's almost a pilgrimage for glider pilots. They are particularly fine examples though.

 

[AndrewB]

How about this one ...

(Appeared here before, but worth reposting).

 

[Leighb]

I saw this weird one over the blackwater

http://www.keepturningleft.co.uk/the-journey/scuttlebutt-38-one-big-cloud/

no idea what it is called

D

I believe it is called a "Roll cloud" usually accompanied by a severe squall line. Worth keeping well away if sailing, or getting some reefs in.

 

[Sgeir]

I saw this weird one over the blackwater

http://www.keepturningleft.co.uk/the-journey/scuttlebutt-38-one-big-cloud/

no idea what it is called

Eric?

 

[Searush]

I believe it is called a "Roll cloud" usually accompanied by a severe squall line. Worth keeping well away if sailing, or getting some reefs in.

My first thought was it looks like a nasty front rolling in!

 

[dylanwinter]

it was accompanied by this

My first thought was it looks like a nasty front rolling in!

this is the whole story of the storm

it was a real cracker

very pleased to have a short mast and to be moored up to a stout mooring bouy

I loved every minute of it

http://www.keepturningleft.co.uk/the-journey/storm-in-west-mersea/

 

[lenseman]

I saw this weird one over the blackwater

http://www.keepturningleft.co.uk/the-journey/scuttlebutt-38-one-big-cloud/

no idea what it is called

D

The last time I saw one of those 'tube' clouds was when I was on the Austria/Liechtenstein area in 2004.

Given the right conditions, they are the precursor to a tornado in the USA where they start to rotate and then stand up on end to form a funnel and as stated above are bad news when out sailing.

 

[oldharry]

Saw these beauties over Trawsfyndd, N Wales several years back:

 

[SHUG]

...but what does it all mean weatherwise???

 

[dylanwinter]

excellent pix Harry

well done

if I had taken them I would very pleased with those

beautifully done

Dylan

 

[GrahamM376]

...but what does it all mean weatherwise???

Requires stable air usually found in pre-frontal conditions. Flying in wave lift is magic as long as you stay in the lift which can be well over 1000ft per minute. World gliding altitude record is over 50,000ft! (mine's somewhat lower) However, trying to hop to the next lenticular takes you through the "sink" at the same rate. Some years ago a Boeing 707 lost its wings over Mt Fuji when flying through the sink/lift bands.

 

[salinia]

Conwy N Wales -

 

[johnalison]

We don't get many lenticular clouds in Essex but I just managed to take 3 panoramic snaps of this thunderstorm in N Germany this summer before it poured with rain.

 

[GibseaRob]

...but what does it all mean weatherwise???

Lenticular clouds form over pronounced high ground where the air is forced upwards quickly. There must also be an inversion layer above the high ground (a layer of air that is warmer than that below). When the air below rises up the mountainside and meets the inversion layer, it causes rapid cooling and condensing of the warmer air before 'falling' back down the other side. The 'UFO' shaped cloud is the product.

The stronger winds needed to produce these clouds are compounded by the Venturi effect as they are channeled over the crest, as well as repeating this process several times as it crosses the range. This can result in 'Mountain Waves' extending beyond the high ground quite some distance (maybe 50 miles) before they die out. These are characterised by sharp, powerful squalls as the downward draught hits the surface, followed by cyclonic lighter conditions underneath the wave. You may experience this in St George's channel in a strong easterly.

It is right that the approach of a warm front may assist in the formation of the lenticular clouds by providing the required inversion (refer to a diagram of the makeup of a frontal system).

 

[oldharry]

Well, the weather the next day was horrendous! Real Welsh rain of the wettest variety and a rare old breeze which made me glad to be ashore. Real holiday weather!

And thanks, yes Dylan - I was dead chuffed with the result.