Australia is facing record warmth and drought as winter approaches, forecasts show

This year, for many Australians, summer feels like it will never leave. Sunny and warm nights continued into autumn. It’s still unusually warm in May.

Much of the southern half of the continent experiences both unseasonable warmth and dryness. This is linked to sustained high pressures (called “blocking”) to the south and southeast of Australia.

As we approach the winter solstice, temperatures drop in southern Australia, but early signs indicate that this winter will be warmer. Rainfall forecasts are not very certain.

The extra warmth we experience raises clear questions about the effects of human-induced climate change. The warming signal is clear, and it is a sign of what’s going forward.

Warm and dry autumn for many

March and April brought the heat of the season to much of Australia.

March was broad and hot, with temperatures a few degrees higher than normal for most parts of the country. However, April’s heat was primarily confined to the southeast.

Victoria recorded its warmest April in April, with parts of the state experiencing temperatures above 3°C than usual in both March and April.

Temperatures usually drop very rapidly in the southeast of Australia between April and May, shortening the days and cooling the interior of the continent. However, this year, southern Australia was unusually warm in early May. In some locations, the daily experience was at maximum temperatures above the normal 10°C during the time of year.

Records were broken in parts of Hobart and Melbourne. Melbourne had the warmest May night since observation began.

The coasts of Queensland and New South Wales had very wet spells, including a downpour from the tropical cyclone Alfred at the beginning of March, while the rest of Australia is very dry.

The area between Adelaide and Melbourne is very dry. After a severe lack of rainfall, droughts have been unfolding in the region, which has seen a growing deficit over the past year or so. Western Tasmania has also suffered from a severe lack of rainfall since the beginning of autumn, but the welcome rain last week.

And it is not only the land where extraordinary fever has been observed. The oceans around Australia are warmer than usual, causing serious coral bleaching to the west and east of the continent, causing harmful algal flowers and other ecosystem disruptions.

Blocks highs that are primarily responsible

Over the past few months, high-pressure systems have dominated the south and southeast of Australia.

High pressures in the Tasman Sea can be stuck there for several days. This leads to what is known as “blocking” when normal passage of a weather system moving from west to east is blocked. This can lock weather patterns over a few days or week.

Repeated blocking occurred this fall. As winds move anti-rock circuits around high-pressure systems in the Southern Hemisphere, blocking highs in the Tasman Sea, bringing wet onshore winds to the shores of New South Wales and Queensland, increasing rainfall. However, such high pressure systems result in dry conditions in the southeastern region and most parts of Victoria and South Australia.

In many cases, these high-pressure systems bring north winds to Victoria, which can cause warmer conditions in most parts of the state.

High-pressure systems also tend to provide clearer, clearer conditions, particularly during the daytime. Air in high-pressure systems moves towards the surface, which also causes warming.

Australia is between the Pacific Ocean and the Indian Ocean and is the subject of its fluctuations, so we often look there to help explain what is happening in the Australian climate. However, in autumn, climate effects such as El Niño and Southern vibrations and dipole in the Indian Ocean are less active, and the relationship with Australia’s climate is weaker than in other times. Neither of these climate impacts are at a strong stage at this time.

Warm winter card

One of the big questions is how long the fever lasts. In parts of southeastern Australia, including Melbourne, average temperatures drop rapidly during this time of year as the winter solstice approaches.

However, seasonal outlook from the Weather Bureau indicates that it is likely to be a relatively warm winter.

Australians rarely spend winters, but long distance predictions suggest that on average, normal temperatures should be predicted. Both daytime maximum and nighttime minimum temperatures are generally expected to exceed average this winter.

Global warming is here

The weather in the room is climate change. Human-induced climate change is increasing the frequency of autumn temperatures and late season thermal events. As greenhouse gas emissions continue at a record-breaking pace, we expect a high possibility of continuous warming and autumn heat in the future.

However, the impact of climate change on rainfall is less clear. For the majority of Australia, there is high uncertainty as autumn is wet or dry as the world warms.

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