The Australian Weather Forum

The polar vortex is splitting!

https://earth.nullschool.net/#current/w ... 90.15,2612

Didjman wrote: ↑Mon Jul 22, 2019 8:19 am The polar vortex is splitting!

https://earth.nullschool.net/#current/w ... 90.15,2612

It certainly is very elongated in both the core and the outer band atm.
Notice the big kink near the west Australian longitude.
That is where the stationary warm anomaly is located.
It looks as thought the outer vortex wind band has to go around it.?
Here is a still snap for the archives

Zoom right in-you can see beginning of right hand low

Didjman wrote: ↑Mon Jul 22, 2019 8:29 am Zoom right in-you can see beginning of right hand low

Have you had a look at the 10and 70hpa nullschool.
Is this going on there as well?

At 10 hpa, it is distorted, but not like at 70.

Its official - we have a split in the polar vortex.
https://earth.nullschool.net/#current/w ... 87.02,1159

The jet around it is pushing north; to west of Hobart in the southern ocean!

This is the jets at 250Hpa:
https://earth.nullschool.net/#current/w ... 96,-57.115

These are the current temp anomaly animations at 10 / 30 / 50 Hpa:
https://www.cpc.ncep.noaa.gov/products/ ... 10anim.gif
https://www.cpc.ncep.noaa.gov/products/ ... 30anim.gif
https://www.cpc.ncep.noaa.gov/products/ ... 50anim.gif

Thanks for your updates 'didjman'. We may have quite a way to go yet..
The 2002 polar vortex split was a spring event in september. The build up in August.
We have been monitoring these temp' anomalies much earlier.
Here is a documentation of the 2002 event

Its a little hard but useful
Some research on the 2002 event

The Splitting of the Stratospheric Polar Vortex in the Southern Hemisphere, September 2002: Dynamical Evolution
Andrew J. Charlton, Alan O’Neill, William A. Lahoz, and Paul BerrisfordDepartment of Meteorology, University of Reading, Reading, United Kingdom

https://journals.ametsoc.org/doi/full/1 ... JAS-3318.1

We could be at the start of a complete split
Looking at what happened on 2002.
source
https://www.ecmwf.int/sites/default/fil ... uthern.pdf

TIME Frame


and our current 10 hPa looks the same.as the start of the major split at 10hpa
aource
https://www.cpc.ncep.noaa.gov/products/stratosphere/


Lets observe..


Lets observe.

crikey wrote: ↑Mon Jul 22, 2019 9:22 pm

and our current 10 hPa looks the same.as the start of the major split at 10hpa
aource
https://www.cpc.ncep.noaa.gov/products/stratosphere/

Hi Crikey,
I must be missing something; I can't find that chart(or links to it).

Sorry for not providing that link
Here tis'
https://www.cpc.ncep.noaa.gov/products/ ... _a_f/#emct

BTW l am not disputing there has been a split in the central vortex at 50-70hPa.,There were obviously 2 vortices.
I am just making some comparisons to the 2002 event where the 10hPa seems to be mostly documented.
Apparently there needs to be a zonal wind change in the vortex from west to east to,signify a complete split.
I will try and get a link for wind anomaly today and check those obs' out
There are similar features to the 2002 event .,For example,the stall in those rotating temp' anomalies was also observed before the 10hPa split .

Interesting and many thx

Vortex partial split is now easy to see at 70Hpa:
https://earth.nullschool.net/#current/w ... -74.12,488

At 10Hpa, distorted but whole:
https://earth.nullschool.net/#current/w ... -88.39,488

Thanks for the updates 'didjman'.
I finally had a go myself at 'nullschool'
and snapped this today of the 10hPa.
Note the strong anti cyclone .
The 2002 vortex split literature noted one anti cyclone either side of the vortex before the major split, l thought l read..
I wonder if we will be lucky enough to see a 2002 replay in 2019?



also snapped this anomaly today. It looks impressive but don't know enough to give a commentary

Polar jet is looking strong now at 250Hpa:
https://earth.nullschool.net/#current/w ... -51.61,783

Polar vortex at 70Hpa, local time 0400:
https://earth.nullschool.net/#current/w ... -73.99,682

Yes Nice to see the sub tropical jet in a meridonal,(wavy) phase. Its about time.
The sub polar jet still looks weak in my books just a tad better than it was

The evidence also in the SH sat pic with the tropical to polar cloud trains underway.
There is some decent long wave troughing atm at the 200hPa layer
We just need the surface layer respond .
Thanks for your continuing obs'



source
http://www.bom.gov.au/australia/charts/ ... fresh+View

The tropopause has shot up from 9klm to 11.5 in the 12 hrs to 9am this morning

I have been doing a little reading up on tropopause height as your obs' 'didj' are interesting.
A topic l have never bothered with in the past.
Its good to learn something new.
The height of the tropopause
http://www-das.uwyo.edu/~geerts/cwx/not ... tropo.html
I read
'Sometimes the tropopause actually folds down to 500 hPa (5.5 km) and even lower, just behind a well-defined cold front.'

Keep an eye on those 70hPa windstreams 'didj'

I think ....Their is another forecast for a wind reversal at 70hPa. The signature of another central vortex split.
If l am reading and understanding this Zonal wind 70hPa time series map correctly.?

It looks stronger than the one on the 7th July 2019
Maybe l should check the GFS forecast

source
Zonal winds
https://acd-ext.gsfc.nasa.gov/Data_serv ... strat.html

crikey wrote: ↑Wed Jul 24, 2019 3:46 pm Keep an eye on those 70hPa windstreams 'didj'

I think ....Their is another forecast for a wind reversal at 70hPa. The signature of another central vortex split.
If l am reading and understanding this Zonal wind 70hPa time series map correctly.?

70Hpa at 1600:
https://earth.nullschool.net/#current/w ... 88.47,1640

We are back to one vortex with an elongation on one side.
The heating anomaly at 50hpa is stretching and splitting.