The stubborn high-pressure system behind Australia’s record heatwaves



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Parts of Australia have broken multiple heat records over the past week.
Vicki/Flickr, CC BY-NC-SA

Steve Turton, CQUniversity Australia

If you think the weather this month has been like Groundhog Day (albeit much hotter), you’d probably be right! Much like a stuck record, weather systems seem to have stalled over most of the country.

Brisbane residents are questioning the lack of rain, storms and heat. Darwin has just endured its second-latest monsoon onset on record after weeks of heat and humidity. Interior towns and cities have experienced significantly hot weather with a number of new maximum and minimum temperature records broken, along with records for consecutive days over 35℃.




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Perth has largely escaped the heat so far this summer, while Sydney and Hobart have had a mixed bag. Coastal sea breezes have tempered conditions in the south and southeast of the continent. However, heatwaves are forecast for Melbourne and much of the southeast, with the arrival of strong, hot northerly winds. This will also bring extreme or severe fire weather conditions in many areas, including Tasmania. Adelaide, meanwhile, has sweltered through the hottest day on record for any Australian capital.


Bureau of Meteorology

These weather patterns across the country are largely due to a stubborn blocking high-pressure system that has remained over the Tasman Sea since early January, affecting weather on both sides of the ditch. This type of strong high-pressure system typically forms further south than usual, and remains almost stationary for an extended period, thus blocking the west-to-east progression of weather systems across southern Australia.




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Sometimes, these blocking highs position themselves over the Great Australian Bight. They can occur at any time of year, and can stay in the Australian region from several days to several weeks.

This schematic shows a ‘blocking high’ preventing weather systems moving across Australia.
Understanding Climate Change in Australia report

Winds rotate anticlockwise around high-pressure systems in the Southern Hemisphere. On the northern flank of the blocking high, southeast trade winds have been affecting northern New South Wales and eastern Queensland due to a persistent ridge of high pressure. These winds have been largely cool and dry, with only the far north of Queensland experiencing significant showers. The ridge has kept the inland trough further west over inland NSW and Queensland, preventing normal afternoon thunderstorm activity in the inland, and adding to the woes of the extended drought.

Cool, moist weather from the Southern Ocean is being displaced southeast by the blocking high, resulting in prolonged continental heatwaves and lack of rain. On the western flank of the blocking high, hot dry northerly winds from the arid centre are pushing through South Australia and Victoria, generating heatwave conditions.




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Across the ditch, cooler and drier southerly winds are affecting much of New Zealand. Only the southwest of the South Island is getting any significant rain due to persistent moist westerlies on the southern flank of the blocking high.

An unusually strong ridge of high pressure across Queensland, extending up to Cape York, has kept the monsoon trough north of the continent. This pattern is forecast to change as a deep tropical depression forms in the Gulf of Carpentaria over the coming days and moves south into northern Queensland. Unfortunately, the stubborn ridge of high pressure over central Queensland is likely to block the rain-bearing low from moving much further south over drought-stricken parts of inland Queensland and NSW.




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While parts of the country have sweltered, the far southwest of Australia has experienced cooler and wetter than average conditions this month. Cape Leeuwin, Australia’s most southwesterly point, set a 123-year daily rainfall record for January, recording a massive 57mm of rainfall.


Bureau of Meteorology

In the short term, there is no indication that the blocking high will break down or move eastward. Forecasters on both sides of the Tasman expect the pattern to continue until February at least.




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The Conversation


Steve Turton, Adjunct Professor of Environmental Geography, CQUniversity Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Here’s how a complex low-pressure system sent temperatures plummeting



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The complex low weather system currently swirling over south-eastern Australia.
Bureau of Meteorology

Adam Morgan, Australian Bureau of Meteorology

New South Wales, Victoria, Tasmania and South Australia are currently affected by a massive complex low pressure system, dropping temperatures and bringing rain, hail, wind and snow.

While complex low pressure systems like this come along every year or so, some Australians may be feeling whiplash after a particularly warm autumn.

Complex lows

Typically, as Victoria and Tasmania head into winter we see cold fronts that move from west to east, generating rain and thunderstorms. This weather system started off like that, but developed into a complex low that will stay with us for the rest of the week.

It’s the kind of weather system you see on average once every year or two. What is a little unusual is to see such a deep pool of cold Antarctic air so early in May. Canberra, for example, is forecast to have a maximum of 9℃ on Friday – which would be its coldest day in the first half of May since 1970.




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In weather-speak, “complex” describes a weather system with an intricate structure. Starting as a cold front across Victoria and Tasmania, this complex low now has multiple low-pressure centres at the surface, and is interacting with a broad low-pressure system in the upper levels of the atmosphere. These upper and low-level weather systems reinforce each other.

The other factor contributing to the complexity is the warmer waters of the Tasman Sea. The East Australian Current brings warmer waters down the east coast, raising ocean surface temperatures in the Tasman Sea relative to the neighbouring Bass Strait and Southern Ocean. When these low pressure systems develop over the western Tasman Sea, that warm water provides a lot more energy through evaporation.

When all the elements align, with a cold front and its associated cold air mass moving over warm water, beneath an upper-level low in the same place providing reinforcement, a deep and complex low-pressure system can develop.

Difficult to predict

The Bureau of Meteorology usually has several days’ indication that a system like this may form, but development of multiple low-pressure centres at the surface makes it tricky to predict exactly where local impacts will strike.

These small-scale low-pressure centres influence exactly where the heaviest rain or strongest winds will be, as do features of the landscape like mountain ranges.

While we can make broad predictions of what may be on the way, it’s not until we get closer to the event that we can really start to be more specific about rainfall totals, wind speeds, and so on.

The Bureau gets minute-to-minute readings from our Automatic Weather Stations, but we have the ability increase the frequency of some of our measurements (for example, at the moment we have increased the frequency of weather balloon releases at Hobart airport), to get additional information about the atmosphere.

This system will move fairly slowly over the next couple of days, and different elements will impact different parts of Australia.

We’ve got cold air, wind and showers over Victoria and southern New South Wales at the moment, but there are parts of the east coast that are still quite warm today. Tasmania is starting to see windy conditions in Hobart and rain developing, and potentially heavy rain through the east of the state over the next couple of days.

Once the cold air moves further north into NSW we’ll expect snow at lower levels as far north as the Central Tablelands, and then as we move into the weekend the low pressure system will move out into the Tasman Sea.

We’ll then start to see swell increase, as the ocean responds to the weather system. Heavy swell and hazardous surf conditions could push well north along the NSW coast and potentially into southern Queensland by early next week.

Weather warnings

Currently, severe weather warnings for wind have been issued across parts of South Australia, Victoria, New South Wales and Tasmania. Heavy rain warnings and flood watches are in place in Victoria, and flood watches and warnings are current in Tasmania as well.

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Other specific warnings provide important information for those on the land – the Bureau has alerted sheep graziers, for example, to the impacts of cold, wet and windy conditions on exposed livestock.

While these warnings are all fairly standard for this kind of weather system, always follow the advice of emergency services. We’re the weather experts, but they’re certainly the experts on preparing for hazardous weather!




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The ConversationWe’d also advise everyone to keep up with the forecasts and warnings on the Bureau of Meteorology over the next few days.

Adam Morgan, Senior Meteorologist, Australian Bureau of Meteorology

This article was originally published on The Conversation. Read the original article.

Australia: Temperatures Mean Map Changes


The link below is to an article that reports on the Bureau of Meteorology in Australia having to add additional colours to the temperature map graphic of Australia for the extreme temperatures currently being experienced in Australia.

For more visit:
http://www.smh.com.au/environment/weather/temperatures-off-the-charts-as-australia-turns-deep-purple-20130108-2ce33.html

Australia: Catastrophic Bushfire Conditions Generate Massive Bushfire Across the South East


South-Eastern Australia is in the grip of a heatwave with temperatures threatening the record books. Temperatures across the country are reaching between 40 degrees Celsius (104 degrees Fahrenheit) and 50 degrees Celsius (122 degrees Fahrenheit), with the hottest recorded temperatures in many centres threatened, as well as the highest temperature every recorded in Australia.

For more on the fires visit:
Battlefront NSW: State on bushfire red alert | News.com.au.

KENYA: CHURCH STRUGGLING AFTER ISLAMISTS DESTROY BUILDING


Six months after attack, Muslim assailants still at large; weary congregation faces heat, rain.

GARISSA, Kenya, March 5 (Compass Direct News) – Six months after a gang of Muslim youths ruined a church building in this town in northern Kenya, Christians still worshipping in the sweltering heat of the open air say they feel disillusioned that officials have done nothing to punish the culprits or restore their structure.

On a sunny afternoon last Sept. 14, when angry Muslim youths threw more than 400 members of the Redeemed Gospel Church out of their church building, the Christians hoped they would be able to return to the ruins of their former structure. That hope is quickly giving way to anger, hopelessness and despair.

“After six months in the open, the church feels tired and cheated,” said pastor David Matolo. “We are fed up with the empty promises from the government administration.”

He said the church, which began worshipping in Garissa in early 2001 with only a dozen members, is fast shrinking.

“Our church membership has decreased, which is of great concern to me,” he told Compass. “The church thinks that the government has decided to buy time – almost every month I do book appointments with the relevant authorities, who on several occasions have given us a deaf ear.”

Since the attack, church members have been meeting at the town show grounds. Just a few miles from the Somali border, the site has few trees to protect the congregation from the scorching sun, with temperatures ranging from 92 to 104 degrees F (30 to 40 degrees C).

Asked why he thought government officials were reluctant to grant the church a permanent place of worship as promised, an irritated Matolo did not hesitate to reply.

“The administration has decided, ‘kutesa [inflict pain on us],’ always making promises that never come to pass,” he said. “At times the provincial commissioner deliberately decides not to take my phone calls. I have had a painful experience.”

Matolo said he has asked the administration either to allow the church to build a new structure on land lying idle near a police training college or to let them return to their original site. “We are ready for any eventuality,” he said. “We feel that the administration is not concerned about our spiritual welfare.”

Asked about the pastor’s complaints, provincial police officer Stephen Chelimo told Compass, “The issue at the moment is not within my docket, but wholly rests upon the provincial commissioner.”

But Provincial Commissioner Stephen Maingi said the onus rested on the district commissioner. “Let the district commissioner sort this issue with the pastor,” Maingi said.

District Commissioner Onyango Ogango, in turn, indicated the church itself was the source of problems.

“If the church is allowed to return to their original site, we will expect a fight to erupt with the Muslims,” Ogango said. “Earlier on, the church began very well during its initial stage of inception with controlled worship, but later it turned out to hold noisy prayers and loud songs.”

Further questioned about these allegations, however, Ogango said he would call the pastor to discuss a resolution. Even so, Matolo said previous contact with the district commissioner did not leave him with high expectations.

“Our district commissioner seemed to have no feelings for our predicament,” he said. “The faces of the congregation members speak a lot.”

A glance at the worshippers confirmed his appraisal. They looked weary and anxious, with impending April rains expected to add to the indignity of their situation. Matolo said his congregation feels that soon it will be difficult to worship at all.

Even a temporary home did not appear to be forthcoming. The pastor said their request for a site near the provincial commissioner’s residence was dismissed on the grounds that it would create a security concern.

 

Radical Islamic Influence

Tensions between Christians and the Muslim-majority population in the semi-desert town of 20,000 people began in June 2007, when Muslims built a mosque too close to the church building – only three meters separated the two structures.

Matolo said pleas to District Commissioner Ogango did nothing to reverse the encroachment of Muslim worshippers.

Land issues alone have not been responsible for tensions in the area. The Rev. Ibrahim Kamwaro, chairman of the Pastors’ Fellowship in Garissa, said Matolo had offended Muslims when he preached to a lame Muslim man. Muslims were said to be upset that the pastor persuaded the disabled man to stop going to the mosque and instead join his church.

Matolo’s alleged promise to the disabled man of a better life offended area Muslims, Rev. Kamwaro said.

Christians feel increasingly hunted and haunted as the spread of Islamic extremism is fast gaining ground in this town, located about 400 kilometers (249 miles) from Nairobi, the capital. In neighboring Somalia, newly elected President Sharif Sheikh Ahmed on Feb. 28 offered the introduction of sharia (Islamic law) in exchange for a truce with a rebel extremist group said to have ties to al Qaeda, al Shabaab; the rebels said they would keep fighting. Many fear that Muslim youths in this lawless part of Kenya will be tempted to adopt the radical, uncompromising posture of the fighters.

To date, the gang of more than 50 Muslim youths who attacked worshippers and brought their church to ruins have not been apprehended. Members of the congregation feel justice is increasingly elusive.

In Garissa, Muslims restrict churches in other ways. Christians are not allowed to pray, sing or use musical instruments in rented homes owned by Muslims. No teaching of Christian Religious Education in schools is allowed; only Islamic Religious Knowledge is taught.

Garissa has more than 15 Christian denominations, including the East Africa Pentecostal Church, the Redeemed Gospel Church, the Anglican Church, Deliverance Church, Full Gospel Churches of Kenya and the African Inland Church.

Report from Compass Direct News

AUSTRALIA: GIGANTIC SUPER-FIRE FEARED


In the midst of Australia’s worst peacetime disaster that has claimed 183 lives plus (possibly in excess of 300), left 7000 homeless, destroyed 1000 houses and countless other buildings, their is now a fear that bushfires will merge and create a gigantic super-fire that could erupt by the coming weekend into another firestorm.

Bushfires continue to rage across Victoria, with some 23 fires still regarded as out of control. Various towns are still regarded as under threat and the list of towns being threatened by the bushfires continues to grow.

Fears of a gigantic super-fire have emerged following the ignition of several new fires due to lightening strikes between two major fires in the east of Victoria. These fires have the potential to bridge the gap between the two fire fronts.

The 220 000-hectare Kilmore, Marysville and Healesville fire is now only separated by 18 kilometres from the 25 000-hectare Bunyip fire. The threat of these two major fires merging is very real given the strong winds and predicted high temperatures over the coming weekend.

BELOW: Footage of the bushfire in the Kilmore area

AUSTRALIA – BUSHFIRES: THE VICTIMS


The Victorian bushfires have now destroyed over 1200 square miles of bushland, farmland and communities/towns. The fires continue to burn and are expected to burn for several weeks.

Though many communities remain under threat or are coming under threat, the next major threat comes with the approaching weekend and the coming week as temperatures are expected to rise again. It was close to 40 degrees on the west coast today (Perth) – the direction from which our weather patterns come. The crisis is far from over.

The death toll which is officially at 173 is expected to surpass 200 and possibly 300. Unconfirmed reports indicate that an additional 146 bodies were recovered today. There has been no comment from authorities on these reports.

Australian news coverage has begun to show photos of those who have perished in the fires and have begun to identify these various people. It has been reported that 21 people died in one street of one town alone. Many more bodies are thought to be beneath the rubble of destroyed homes.

ABOVE: Kevin Rudd on the Bushfires – Australian Prime Minister

AUSTRALIA: BUSHFIRE CATASTROPHE


Over the last couple of weeks temperatures in south-eastern Australia have been steadily rising and finally reaching searing heatwave conditions in the last week or so. Temperatures have been between 40 and 48 degrees Celsius for almost 2 weeks in may inland areas of Victoria, South Australia and New South Wales. Finally the temperatures have peaked this weekend.

With the searing heat has now come strong hot winds and out of control bushfires. Many bushfires have become uncontrollable and unmanageable to any degree whatsoever and many are beginning to combine. These fires have become massive wildfires and are engulfing huge areas of inland south-eastern Australia.

The worst hit areas are to be found in Victoria where it is now confirmed that at least 65 people have died since Saturday – many more people are injured and missing and the death toll will climb. 700 homes and many other buildings including shops, police stations, service stations, hotels, motels, schools and many other buildings have been destroyed. Whole towns have been practically razed and wiped from the face of the earth.

This disaster is one of the worst bushfire catastrophes to have hit Australia, if not the worst ever. Certainly in the terms of loss of life this is by far the worst fires ever – and the disaster is ongoing, with many fires still burning.

Part 1:

Part 2:

ABOVE: An overview of the fires in Victoria

ABOVE: Bunyip State Forest Fire – photos from the start on Thursday through to Saturday

ABOVE: The Churchill fire in Victoria

ABOVE: Kevin Rudd activates the Commonwealth Disaster Plan

ABOVE: Various other reports

BUSHFIRES FINALLY ARRIVE AS HEAT WAVE CONTINUES


The bushfire season has taken a bit longer than usual to arrive this year, but in the last couple of days bushfires have begun to appear across Australia and in particular in New South Wales and South Australia.

In my region the temperatures rose to the mid thirties (Celsius), while further to the west the temperatures reached the low forties – which has been the case for several days now.

A cooler change is expected in the very near future but temperatures will remain in the mid to high thirties tomorrow before another cool change. The high temperatures will then return at the beginning of next week.

In short, the bushfire season in eastern Australia is now well and truly here and more fires can be expected over the next couple of months – especially given how dry it currently is.

There have been fires around Sydney over the last couple of days with some property (sheds, vehicles, etc) being destroyed by fire today. There have been other fires around, including near Gloucester and Singleton. In South Australia there was a particularly bad fire at Lincoln.

BELOW: Footage of the bushfires