Anyone know what this is?

[jimbunyard]

Any of you weather guys know what the feature to the southwest of the weak cyclonic circulation on the coast of Northern Australia might be called?

The winds all appear to be radiating from the center...

https://earth.nullschool.net/#curren...-89.215,30.110

[CatNewBee]

Originally Posted by jimbunyard

Any of you weather guys know what the feature to the southwest of the weak cyclonic circulation on the coast of Northern Australia might be called?

The winds all appear to be radiating from the center...

https://earth.nullschool.net/#curren...-89.215,30.110

A hot-spot

[Alan Mighty]

Most interesting, Jim. Well spotted!

It is (at the time I write) still in the display of the Earth windmap model.

The Aus Bureau of Meteorology display of its MetEye model shows a hint of its existence (SW of Wadeye, see MetEye - it's an animated display, not a pseudo-real moving one. And you have to zoom and search for it).

So it's not just an artifact of the Earth windmap model.

So it's a vortex. Paired vortices are a thing. In mid-ocean they are called modons (a name coined by Melvin E Stern in 1974-75).

There's a fair bit of literature on the "Fujiwhara effect" when two rotating storms (i.e. intense Lows) interact. That's a vortex pair with the same direction of rotation.

This looks likes a vortex pair with different senses of rotation, just like a modon. So it's perhaps a kind of barotropic vortex pair.

Whether we should call it the two of them a vortex pair is another question. I suspect the second vortex is just one of perhaps several vortices created by the turbulent wind caused by the TC. So just another eddy, not really one paired with the TC.

The vortex counter-rotating to the tropical cyclone is losing energy and is not being sustained (whereas the TC until it crossed land has been growing in energy because of high sea surface temperature), so it will be ephemeral.

[Mr B]

From a freind who lives in Darwin, Its a tropical cyclone, category one, called Marcus,

[Wotname]

Originally Posted by Mr B

From a freind who lives in Darwin, Its a tropical cyclone, category one, called Marcus,

Marcus is the TC near the top right, the OP is asking about the strange feature to the SW of Marcus.

[Mr B]

It may be another cyclone forming, Ive seen two in the gulf start like that, both cyclones,
Another friend I have up there is a crew member on the Malu Chief, Its a supply Barge tied up in Darwin Harbour,
He is putting up current video's of the storm, A sail boat has dragged its anchor in the bay behind him, and is now up on the rocks,
124 Knots of wind, It has changed direction, its now WNW, On his barge,

[IslandHopper]

Originally Posted by Mr B

It may be another cyclone forming, Ive seen two in the gulf start like that, both cyclones,
Another friend I have up there is a crew member on the Malu Chief, Its a supply Barge tied up in Darwin Harbour,
He is putting up current video's of the storm, A sail boat has dragged its anchor in the bay behind him, and is now up on the rocks,
124 Knots of wind, It has changed direction, its now WNW, On his barge,

Can't help with the op's question, but just for interests sake i was Master of the Malu Chief (Sea Swift barge) back in 2005

[Mike Banks]

I think it is a depiction of rising air from a portion of hot sea--it is over 30 decrees Celsius in that area--because there seems to be no rotation, merely divergence.

But hey--what the heck would I know--I am not there to verify.

[Mr B]

Originally Posted by IslandHopper

Can't help with the op's question, but just for interests sake i was Master of the Malu Chief (Sea Swift barge) back in 2005

You may even know Craig Hand off the Malu Chief,
He did the trip down the east coast from Darwin in the Little Red Boat, A couple of years back,