I was wondering about the storm that clobbered he Gap last month.

I understand there were 2 storm cells that came together and made a small "supercell" which I understand to be an intense cell small in area but extending to a high altitude somewhat like a tornado. (could be wrong)

I'm trying to imagine the mechanics of it.

I thought that all storms were subject to the coriolis effect and rotated in the same direction. In that case if the cells actually joined together you would expect to see winds blowing in opposite directions when they bumped together and cancel each other out but then the winds from both would merge to circulate around the entire area covered by both storms. I don't see how that would increase the intensity.

If I imagine the 2 cells approaching each other then the air between them would be accelerated into a rotating column of the opposite chirality, but that would be a secondary effect not directly generated by the atmospheric conditions that generated the original cells. I don't see how that would be particularly intense either.

Any of you weather boffins understand this stuff?

Regardless of 2 cells - the basics are energy mostly in the form of heat also density - (moisture - preserves the energy) gets accelerated vertically (thunder heads etc) Hi energy to lower energy. Once air reaches saturation point - rain forms - falls - when v.hi - makes small icicles - falls - once vertical (up) overcomes gravity pushes icicle up circles around till finally too heavy to stay up and falls - (different size of hail - bigger more power in system) - if heavy rain then melted on way down. The vertical gusts (can go up some 3+ kms) also generate downward flows (gusts) to balance air mass. Where this is low enough to hit the ground you get very powerful very local cells which can be as ****ty as a small tornado - high intensity short duration - frequently the pressure change inside a roof to air outside can blow roof off a house. - Lots of physics but basically same outcome.
Used to chase down small dustdevils (v.small tornado in shape and movement - different mechanism forms them - frequently triggered thermals) when hang-gliding never too close to ground (100+ metres = rule of thumb I used) - now that was sweaty but great fun...
have kids now - easier to Kite surf.a bit & a bit
cheers SF
(I crashed & dragged at hi speed when learning - alot - amazing how much water drains out - must have cavity space as brain shrinks!!)

my laymans take on it.

it started out as a group of cells along the front which were being sheered by the seabreeze.

2 cells which had formed then pushed up against each other.

1 of those cells directed it's downdraft into the others upflow. this made the shear line move from horizontal to vertical and turned it into a cell containing a mesocyclone. ie. a supercell

after this it would have spun away from the front line and caused all of the damge and potentially spun off a few short lived tornado's/

maybe.

it was interesting to watch the supercell hit us at wello during the first meet. you could see the anvil, the flanking clouds and the wall cloud. as it headed towards us it threw out a tornado right in front of us. awesome stuff.

last year (i think or the year before) i watched 2 cyclones in the coral sea collide. made for spectactular satelite images. from memory they both died. apparently with cyclones they rip each other apart and mostly turn into rain depressions.

i think though with storm cells they can occur close to each other sort of bumping off each other along a front.

Gestalt said...

my laymans take on it.

it started out as a group of cells along the front which were being sheered by the seabreeze.

2 cells which had formed then pushed up against each other.

1 of those cells directed it's downdraft into the others upflow. this made the shear line move from horizontal to vertical and turned it into a cell containing a mesocyclone. ie. a supercell

.....(snip).....

maybe.

What Richifish said....

This is like trying to visualise the vortices in a double food processor. I wonder if it could be replicated by a couple of paint stirrers in a pool?

forgot to add that the shear level is around 900mb and it is our seabreeze that feeds it.

a supercell also needs moisture inflow and temp gradients but that is starting to get a bit heavy for me.

NotWal
Here are some photos of that storm as is gathered strength and moved over the Gold Coast and may be one of the cells that you are refering to.
these photos were taken at Coolangatta Airport

Hope you like them

mineral1 said...

Toadwhispera, huge photo's, they should be entered in a comp some place.

They're awsome but I can't claim them they were sent to me on my work computer
The colour contrasts are great.
To think that that storm hit the Gold Coast and left us virtually unscathed so imagine by the time it moved up the Coast and doubled or even tripled in intensity
what it was set upon Brisbane and how it must have looked