Topic: Tornadoes Tornadoes for the Western Dakotas once again - 13 July 2009

[australiasevereweather]

Tornadoes for the Western Dakotas once again!  Good Heavens
         



A setup very similar to the tornado event last week is in store for the western Dakotas again this afternoon and evenings, as a potent trough ejects from the Northern Rockies.  There are a few MCSs across the central Dakotas early this afternoon, but they should move east and die allowing for strong heating in their wake.  Ahead of this trough, the LLJ is forecast to increase above 30 knots by 21z and increase steadily through evening as the boundary layer decouples.  Supercells will develop in extreme eastern MT and move east into this incredibly unstable and sheared environment by late afternoon into evening.  I typically trust the RUC wind fields most with these Northern Plains setups, but the thermodynamics have been out of control on the RUC all season long, so we can probably divide the 0-1 km EHIs by a factor of at least 2.  I'm still grinding out the dissertation or I'd already be in position west of Dickenson!  It is a little weird watching these events unfold from home...  I'm not used to this!!!  Click on "more" for the 16z RUC 850 mb flow and EHIs at 00z this evening.


http://www.tornadovideos.net/component/content/article/1-latest-news/983-tornadoes-for-the-western-dakotas-once-again-good-heavens
         

[Michael Bath]

Some very nice photos of this event available here:

http://chasetours.com/2009July13.htm

[Kristy Norman]

Wow! The inflow is just crazy and that's a wicked beaver tail! Also love the white 'streaks' in photos three and four, must have been big hail. Awesome!!

[Jimmy Deguara]

Incredible and large storm system. I don't think I see a beaver tail though. The photograph shows an indentation in the shelf cloud system. Nice HP system.

Regards,

Jimmy Deguara

[Kristy Norman]

Jimmy, is that not a Beavers Tail as they are referring to it almost on the ground, is it actually a shelf cloud?
I had a look at another chaser's site extremeinstabilty.com because I couldn't get enough of this amazing storm. He also calls it the beavers tail/inflow and has a lot more shots and different angles of it. Perhaps he is wrong.
Are there different types of inflow bands?

[Jimmy Deguara]

Hi Kristy,

No he is not wrong at all - when you look at this picture, you can see a beaver tail in the earlier stages - the picture above made it difficult to detect the actual position and orientation of the beaver tail. In the picture below, look for the right hand side of the image - you may require to scroll across to the right.

Courtesy Mike Hollingshead     http://www.extremeinstability.com/


Regards,

Jimmy Deguara

[Kristy Norman]

Thanks Jimmy, I also came across this youtube clip of a timelapse of this supercell. Such a monster!
July 13, 2009 AMAZING Supercell Time Lapse

[Colin Maitland]

That time lapse U tube that Kristy84 posted is spectacular, it would have been an adrenalin rush to be there to watch and feel that storm build. I love that eerie feeling as they approach.

Col

[Jimmy Deguara]

What I love about the consistency of US supercells is the clean structure and incredible organisation. There is a lovely clear slot early on in the vision and around 2:40 on the timer, nice inflow streamers. Certainly looks to have been deep inflow - likely from 850hPa down to ground level.

Bloody awesome!

Regards,

Jimmy Deguara

[Richary]

I love that almost ground level inflow (beaver tail?) at the end.

[Jimmy Deguara]

The low hanging cloud is not the beaver tail. It is just an extra shelf cloud developing as moisture increased and outflow began to push outwards.

Regards,

Jimmy Deguara

[Colin Maitland]

On the second post of this thread MB posted the link  http://chasetours.com/2009July13.htm  from www.chasetours.com and on the 11 photo the caption says  8:47 PM - Next photos feature the amazing inflow bands feeding this supercell the inflow band near/on the ground is called the "Beavers Tail "

Then on frame no12 it states  8:53 PM "Beaver" on the ground

I think that's why Richary stated  beaver tail with question mark,

I love that almost ground level inflow (beaver tail?) at the end.

When I first saw the photos as well, I got a bit confused if that was the beaver tail, as we already spoke about in another thread, or have they wrongly classified the shelf cloud as to being the "Beaver tail"? (late edit forget to put in ? mark )

Thanks

Col

[Michael Bath]

I think the comment on the website "the inflow band near/on the ground is called the Beavers Tail" is referring to several photos. The photos depict how the features change between 8.45 and 9.04pm

In this photo the inflow band is the smooth laminar cloud above the ragged feature on the ground:



In this one the inflow band and shelf have evolved/merged and you can say it is now a beaver tail near/on the ground:

[Colin Maitland]

Thanks Michael, I can see that now that you have explained it, and it makes sense to what Jimmy and John Allen had explained in a previous thread.

Col