weather quiz!

[Morgan Palmer]

i think it's a fumarole- mp

EDIT: nope that's wrong. A fumarole is from a volcano.

 

[Andy Wehrle]

It's called a fulgurite. Heard it somewhere. Not from TWC but from some weather book or article I read. The "WV Lightning" chase site has more information: http://www.wvlightning.com/ld-fulgurite.html

 

[Robert Dewey]

Originally posted by Andy Wehrle
It's called a fulgurite. Heard it somewhere. Not from TWC but from some weather book or article I read. The \"WV Lightning\" chase site has more information:http://www.wvlightning.com/ld-fulgurite.html

Yes! That is correct...

Speaking of WV Lightning, that site is run by Dan Robinson - what ever happened to him? He used to be here all the time...

 

[B Ozanne]

A little interuption and defense of Mount Washington. After all, I am an intern at the observatory. I'm headed back up for another week on the mountain on Wednesday.


Of course, Mount Washington does have the highest recorded wind speed, 231 mph. Yes, for a few days Guam took the record but it was found that their anemometer was terribly inaccurate. They actually used a thermal device to measure the wind speed. Speed was determined by how quickly the device cooled down. It was never properly calibrated, especially with all that rain.

Back in the day they guys on Mount Washington were using a modified cup-style anemometer. They counted the clicks it made as it rotated around. Today, we use a static pitot anemometer. It is just a modified airplane pitot. The wind pushes on a column of water and we determine the wind speed based on the height of the column. Earlier this month we peaked at around 150mph. We have extreme icing conditions and the primary pitot went down during the storm from ice. So we had to manually hold the backup pitot in the wind. That was fun! Our best guess is the winds were higher as the backup pitot could not be held as high as the primary, plus we could only hold for a few minutes an hour.

Sorry, about the interruption. If anybody has any questions about the weather or life on Mount Washington please send them my way.

 

[Patrick Kerrin]

Which cloud is the announce of the evolution between cumulus congestus and cumulonimbus?

.

I hate to picky but isn't the distinction beween cumulus congestus and a cumulonimbus the initial glaciation of the updraft into an anvil (which implies charge separation).

The cap cloud (Pileus) is just that - a cap cloud - which, IIRC, is a cap of supercooled condensation associated with the rapid displacement of air above a rapidly growing cumulus tower in a sufficiently moist layer.

 

[Patrick Kerrin]

And to be picky on myself....

Originally posted by Patrick Kerrin
... the distinction beween cumulus congestus and a cumulonimbus the initial glaciation of the updraft into an anvil (which implies charge separation).

I should probably also say that for updrafts that do not glaciate (i.e. remain cumuliform) I would make the distiction between cumulus congestus and cumulonimbus being when either the Equilibrium Level is reached/surpassed and/or charge separation has occurred and the cell is electrified.

 

[Laura Duchesne]

Hi Patrick! I think you make a valid point. Pileus clouds don't really tell you that the cumulus congestus will transform into a cumulonimbus. It's just a cap cloud. I think the cloud that should tell you when a cumulus congestus reaches cb stage is when it starts to glaciate, forming an anvil. I don't think pileus will tell you for sure that the cumulus congestus will transform into a cb. I guess it would be a sign that it is growing, but I have seen pileus caps on towers that never did end up glaciating.

 

[Patrick Kerrin]

Originally posted by Laura Duchesne
I think the cloud that should tell you when a cumulus congestus reaches cb stage is when it starts to glaciate, forming an anvil. I don't think pileus will tell you for sure that the cumulus congestus will transform into a cb. I guess it would be a sign that it is growing, but I have seen pileus caps on towers that never did end up glaciating.

Laura, I agree that any glaciated anvil is certainly a CB. The reason I made my second post was that I forgot to add that one should also consider that many (most?) supercells have unglaciated cumuliform anvils and cumuliform overshooting tops (and certainly anvil "knuckles" are unglaciated). In such situations I take it that the cloud matter is still supercooled condensation and these are also certainly CB and not CC (i.e. I take the delineation between CC and CB as the arrival and spreading of convective condensate at the EL and/or having evidence of charge separation).

And yes, the Cap Cloud results from the rapid displacement of air associated with the convective process.

 

[DELIGNY Vincent]

Second checkpoint of "weather quiz!": :shock:


Quebec: 145 replies:
http://natureinsolite.com/meteochat/viewto...opic.php?t=1352

UK: 142 replies:
http://www.ukweatherworld.co.uk/forum/thre...d=16448&start=1

France: 82 replies (infoclimat):
http://forums.infoclimat.fr/index.php?showtopic=6064

Italie: 57 replies:
http://forum.meteogiornale.it/viewtopic.php?t=14209

USA: 52 replies:
http://www.stormtrack.org/forum/viewtopic.php?t=4177

Espagne: 34 replies:
http://www.meteored.com/foro/index.php?boa...;threadid=17068

:shock: France toujours 3ème !!!! aller les gars! :wink:

 

[DELIGNY Vincent]

:roll: ok
For stormchasers and weather fascinate people; the weather quizz continue here:
8) http://fryz.forumactif.com/viewtopic.forum?t=44 8)
It's to keep this interesting topic :wink:

 

[DELIGNY Vincent]

:cry: i've post a new question about weather and i've link this topic page here:

:arrow: http://fryz.forumactif.com/viewtopic.forum?t=44

it's just for you.... if you are interesting about weather knowledge :!:
:wink:

 

[Joe Nield]

Looks like a shelf cloud. The lowered area could be easily mistaken for a wall were it sloping into the darker area of the photo, and one could determine what the darker area is.

On the evening of May 24, 2004, we saw many wall look-alikes on the leading edge of the line that eventually hammered Beatrice, NE while watching from our second floor window in the Super 8.

 

[DELIGNY Vincent]

[Broken External Image]:http://membres.lycos.fr/fryz2002/hpbimg/F1000009web.jpg
In french this cloud name is "Arcus"
the photo web page:
http://membres.lycos.fr/fryz2002/photoalbum18.html
:wink:
We continue with a another question?