Australian High

Short description: Semi-permanent high-pressure system over Southern Australia

Australian High

The high featuring an anticlockwise rotation around an oval area of clear skies.

Area of occurrence|

* Great Australian Bight, Western Australia and Southern Australia (summer)
* Central, eastern, and northern Australia (winter)

Season| All-year round
Effect|

* Drought in the west and south (summer)
* Drier conditions, and at times drought, in the centre, north and east (winter)

The Australian High, also known as the Australian subtropical ridge,[1] is a large, semi-permanent high pressure area or subtropical anticyclone that seasonally vacillates between the Great Australian Bight in the south to the Northern Territory in the north.[2] It is generally located between 25 and 40 degrees of south latitude, depending on the season.[3][4]

In summer, it typically sits over southern Australia as an Australian Bight High,[5] where it generally provides dry weather in the proximate region. In winter it normally moves north, therefore permitting cold fronts and low pressure systems to relocate up from the Great Australian Bight and bring rainfall to most parts of southern Australia.[6] The high is part of the subtropical ridge system and it is the reason why a large part of Australia is arid to semi-arid.[7]

## Contents

* 1 Description
* 2 Effects
* 2.1 Effects on Asia
* 3 Tasman High
* 4 See also
* 5 References
* 6 External links

## Description

The Australian High west of Tasmania over the Indian Ocean

The Australian High tends to follow the seasonal variation in position of the sun; it is strongest and most persistent during the southern hemisphere summer and weakest during winter when it shifts towards the interior of Australia, as the westerly frontal systems becomes more active in the region around the Bight, thereby allowing cold fronts and low-pressure systems to perforate the southern states.[8]

This high-pressure block exhibits anticyclonic behaviour, circulating the air anticlockwise. It remains almost stationary for a prolonged period over the Bight, hence obstructing the typical easterly procession of weather systems across southern Australia.[9]

A cloud hole with an expansion as far as 1,000 kilometers (620 miles) has been observed, with tops of 1,040 millibars. The high may be extensive enough to interconnect with the Tasman High over in the Tasman Sea, just near New Zealand.[10][11]

## Effects

The high tends to keep the southern half of Australia mostly clear and dry.

The anticyclonic circulation produces a dry climate, bringing warm to hot weather in the southern Australian summer. The high influences the weather and climatic patterns of vast areas of Australia; The aridity of the Australian deserts and the summer drought of southern Australia is due to the large-scale subsidence and sinking motion of air in the system.[12]

In winter, when the high remains stationary in southern Australia (in a positive SAM phase), it can block or replace cold fronts from the Bight, thereby allowing warm weather to the southeast.[13] However, when the high remains fixed south of Western Australia, it can drive in polar air towards the continent, whereby increasing snowfall and rain in the southeast, particularly areas that lie west of the Great Dividing Range (due to the foehn effect).[14] Conversely, a large high stationed below South Australia can bring persistent rainfall to the east coast of Australia, whilst proving clear conditions to Tasmania.[15]

In the western part of the high, hot dry northerly winds from the dry centre push through South Australia and Victoria, ensuing heatwave conditions in these regions. The Australian High is one the drivers of the Southerly buster, which occurs in the southeast coast in the summer.[16] In winter, when the high pressure system is broad over the Australian landmass, widespread frost may occur.[17]

### Effects on Asia

During the southern winter, the Australian High is one of the driving forces behind the South Asian Monsoon. Easterly winds blow from the center of the high towards Asia, and are deflected in a southwest direction towards India after crossing the equator due to the Coriolis effect.

## Tasman High

Between summer and autumn, the high over southern Australia may be linked, or would intertwine, with the Tasman High in the southern Tasman Sea. When the high stalls in the Tasman Sea and becomes a blocking high, New Zealand and Tasmania will generally experience warm and generally dry weather, whilst the east coast of Australia (particularly southern Queensland and New South Wales) will experience moist onshore flows, particularly during a La Niña phase.[18] In March 2021, and also in February and March 2022, a stubborn blocking high in the south Tasman Sea caused heavy rain and flooding over large parts of Southeast Queensland and coastal New South Wales.[8][19][20]

## See also

* Climate of Australia
* Brickfielder

## References

1. ↑ An assessment of relationships between the Australian subtropical ridge, rainfall variability and high-latitude circulation patterns by Dr Allyson A.J. Williams and Dr Roger C. Stone. Queensland Climate Change Centre of Excellence, Nambour, Queensland.
2. ↑ An Australian "Anti-storm" EOS Project Science Office at NASA Goddard Space Flight Center. 5 June 2012.
3. ↑ Summary of Weather Terms Bushwalking Leadership. Retrieved 7 April 2022.
4. ↑ The Sub-tropical Ridge Bureau of Meteorology. Retrieved May 31, 2023
5. ↑ Australian Bight High slows down GSC front runners and could reshuffle rankings by Marco Nannini from Global Solo Challenge. Retrieved 12 July 2024.
6. ↑ Sub-tropical Ridge Example. Bureau of Meteorology. 2 April, 2008. Retrieved 31 May, 2023.
7. ↑ Subtropical ridge leaves us high and dry this June Bureau of Meteorology. July 2017. Retrieved 31 May, 2023.
8. ↑ 8.0 8.1 STALLED WEATHER: HOW STUCK AIR PRESSURE SYSTEMS DRIVE FLOODS AND HEATWAVES by Steve Turton from PreventionWeb.net. 3 March 2022
9. ↑ Southern Annular Mode: The climate 'influencer' you may not have heard of By Kate Doyle from ABC. 14 August 2018. Retrieved 7 April 2022.
10. ↑ High pressure systems: everything you need to know by Ben Domensino from Weatherzone. 21 May 2018. Retrieved 22 April 2022.
11. ↑ THE CLIMATE KELPIE BLOG: Where have our winters gone? by Climate Kelpie. 6 May 2020.
12. ↑ Extreme heat on its way to northwest WA by Ben Domensino from Weatherzone. 12 February 2022. Retrieved 7 April 2022.
13. ↑ Sydney's record 15-day spell of 20 degree winter days by Ben Domensino from Weatherzone. 23 August 2021
14. ↑ Australian snow, rain and heat linked by blocked weather systems, climatologist says By Ben Deacon from ABC Weather. 9 June 2022.
15. ↑ Unrelenting high pressure dominating Australia’s weather by Ben Domensino from Weatherzone. 7 May 2024. Retrieved 9 May 2024.
16. ↑ Modelling coastally trapped wind surges over Southeastern Australia. Reid, Helen J. 1999. UNSW
17. ↑ Frost expected across nearly every state and territory in Australia this weekend By Tyne Logan from ABC News. 27 May 2023.
18. ↑ Special Climate Statement—record warmth in the Tasman Sea, New Zealand and Tasmania Bureau of Meteorology. 27 March 2018
19. ↑ THE CLIMATE AND WEATHER OF NELSON AND TASMAN 2nd edition G. R. Macara
20. ↑ Weather: Blocking high expected to keep much of country warm, mostly dry for last days of summer by Michael Daly from Stuff. February 23 2021.

## External links

* An assessment of relationships between the Australian subtropical ridge, rainfall variability and high-latitude circulation patterns.
* Influence of Global-Scale Variability on the Subtropical Ridge over Southeast Australia

* v
* t
* e

Cyclones and anticyclones of the world (Centers of action)

Concepts|

* Anticyclonic storm
* Storm
* High-pressure area
* Low-pressure area
* Rapid intensification
* Central dense overcast
* Annular tropical cyclone
* Bar (tropical cyclone)
* Superstorm
* Hypercane

Anticyclone|

| Northern Hemisphere|

* North Polar High
* Siberian High
* Azores High
* North American High
* North Pacific High
* Ridiculously Resilient Ridge
* Subtropical ridge

|

Southern Hemisphere|

* South Polar High
* South Atlantic High
* South Pacific High
* Kalahari High
* Subtropical ridge

Cyclone|

| Synoptic scale|

| Surface-based|

| Polar|

* North Polar low
* South Polar low

|

* v
* t
* e

Extratropical cyclones

Concepts|

* Anticyclonic storm
* Storm
* Cyclone
* Post-tropical cyclone
* Low-pressure area
* Weather bomb
* Sting jet
* List
* Rainband

Northern Hemisphere|

| North America|

| Continental|

| Lee Cyclone|

* Alberta clipper
* Colorado low
* Great basin low

|

Other|

* Panhandle hook
* Witch of November

Oceanic|

* Aleutian Low
* Hatteras low
* Nor'easter
* Gulf low
* Pacific Northwest windstorm

Europe|

* v
* t
* e

European windstorms

Historical|

* Grote Mandrenke
* Burchardi flood
* Great Storm of 1703
* Great Storm of 1824
* Night of the Big Wind
* Moray Firth fishing disaster
* Tay Bridge disaster
* Eyemouth disaster

20th century|

* Iberia 1941
* North Sea flood of 1953
* Hurricane Debbie 1961
* North Sea flood of 1962
* 1968 Scotland storm
* Quimburga 1972
* Gale of January 1976
* December 1981 windstorm
* Ex-Hurricane Charley 1986
* Great Storm of 1987
* Burns' Day storm 1990
* New Year's Day Storm 1992
* Braer Storm of January 1993
* Christmas Eve storm 1997
* Boxing Day Storm of 1998
* Anatol 1999
* Lothar and Martin 1999

2000s|

* Oratia 2000
* Jeanett 2002
* Gudrun 2005
* Per 2007
* Kyrill 2007
* Emma 2008
* Klaus 2009
* Xynthia 2010
* Berit 2011
* Friedhelm/Bawbag 2011
* Joachim 2011
* Dagmar 2011
* Andrea 2012
* St Jude 2013
* Xaver 2013
* Dirk 2013
* Tini 2014
* Elon and Felix 2015
* Niklas 2015
* Egon 2017
* Thomas (Doris) 2017
* Zeus 2017
* Xavier 2017
* Ophelia 2017
* Herwart 2017
* Eleanor (Burglind) 2018
* Friederike (David) 2018

2015–present|

* 2015–16
* 2016–17
* 2017–18
* 2018–19
* 2019–20

See also|

* List of European windstorms
* List of atmospheric pressure records in Europe

Other|

* Black Sea storms
* Icelandic Low
* Genoa low

Asia|

* Western Disturbance
* Continental North Asian storms
* East Asian-northwest Pacific storms

Other areas|

* Arctic
* Kona storm

Southern Hemisphere|

| Australia|

* Australian east coast low
* Black nor'easter

|

Other areas|

* Southern Ocean cyclone
* Sudestada

Subtropical|

* Kona storm
* Australian east coast Low
* Lake Huron cyclone
* Mediterranean tropical-like cyclone
* Thermal

Tropical
(List)|

| Northern Hemisphere|

* Atlantic hurricane
* Cape Verde hurricane
* Pacific hurricane
* Typhoon
* North Indian Ocean tropical cyclone
* Mediterranean tropical-like cyclone

|

Southern Hemisphere|

* South-West Indian Ocean tropical cyclone
* Australian region tropical cyclone
* South Pacific tropical cyclone
* South Atlantic tropical cyclone

Upper level|

* Cold-core low
* Polar vortex
* Upper tropospheric cyclonic vortex

Mesoscale|

| Mesoscale ocean eddies|

* Catalina eddy
* Haida Eddies

|

Mesoscale convective system|

* Wake Low
* Mesohigh
* Mesoscale convective vortex
* Line echo wave pattern

Whirlwind|

| Major|

* Mesocyclone
* Supercell
* Low-topped supercell
* Wall cloud
* Funnel cloud
* Tornado
* Multiple-vortex tornado
* Satellite tornado
* Anticyclonic tornado
* Landspout
* Waterspout

|

Minor|

* Gustnado
* Dust devil
* Steam devil
* Fire whirl

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Australian High. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Earth:Australian_High&oldid=3998072"
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template