Welcome to the Bureau of Meteorology's severe weather outlook for October 2018 to April
2019.
Although severe weather can occur at any time of the year, this period is the peak time
for bushfires, heatwaves, flooding, tropical cyclones and severe thunderstorms.
In the months ahead, Australia can expect: an increased risk of heatwaves; an elevated
bushfire potential, particularly in the southeast; a below-average tropical cyclone season; a
lower risk of widespread flooding; and a normal risk of severe thunderstorms.
Many parts of the country, particularly through the inland and the southeast, head into October
with very dry soils and vegetation, after well-below-average rainfall since the start
of the year.
2018 has also been exceptionally warm so far.
We expect the remainder of the year to continue warmer and drier than average.
These factors increase the risk of severe weather in some regions, while reducing the
risk in others.
Let's step through the outlook in detail.
Heatwaves are one of Australia's most dangerous types of severe weather.
Warm nights following hot days provide our bodies with little chance to cool down, meaning
heat stress becomes a real risk to human health.
Heatwaves also have a significant impact on agriculture, energy management, and infrastructure.
In the coming months, the chance of extreme heat developing across inland Australia is
increased due to the current dryness of the soils and the outlook for sunny skies.
This raises the risk of heatwaves for much of southern and eastern Australia when winds
draw this heat towards the coast.
With lower rainfall and reduced grass growth over winter, many inland areas will see fire
potential remain near normal.
But dry forests and likely higher temperatures means parts of eastern Australia, will see
an increased bushfire risk.
In the southwest corner on the other hand, the areas of higher bushfire risk come on
the back of better grass and plant growth, increasing fuel loads after winter rains.
For many, the fire season is already underway, with bushfires along the New South Wales coast
during August signalling the start of the fire season around two months earlier than
usual.
When it comes to tropical cyclones, on average we see around eleven develop in the Australian
region each year, with four crossing our coast.
The weather patterns responsible for recent dry and warm conditions would also usually
mean an average to below average number of tropical cyclones for the coming season.
These same weather patterns also suggest a later than normal arrival for the first rains
of this year's northern wet season.
And if an El Niño develops in the coming months, then there's an even greater chance
that we'll see a below-average cyclone season.
Remember though, Australia has never had a season without a cyclone crossing the coastline
and cyclones are rarely spread evenly across the season.
And what the seasonal outlook can't predict is the size, intensity or exact location of
where any cyclone may form.
This means communities right across the north need to remain vigilant throughout the cyclone
season.
The chance of widespread flooding is reduced in the months ahead.
In areas where the land is dry and rivers are low, rain will likely soak first into
soils before filling rivers.
This explains the outlook for lower than average flows through rivers in many catchments.
However localised flooding can occur in any northern wet season.
This is particularly likely with slow-moving tropical lows, which can cause widespread
rainfall and dangerous flooding, even in areas that have been previously been dry.
Last northern wet season, a succession of tropical lows over the Kimberley in Western
Australia saw Broome receive a year's worth of rain before the end of February.
Severe thunderstorms are dangerous because of their potential for heavy rain, large hail,
damaging winds and sometimes, tornadoes.
Severe thunderstorms are more common during the warmer months, particularly in northern
New South Wales, southern Queensland, and across the tropical north.
Across southern Australia, thunderstorm asthma can also be triggered by severe storms, especially
from October to December.
In general, severe thunderstorms and heavy rainfall are more likely across the south
during the warmer months when humidity and moisture extend across the continent from
tropical weather systems.
So, now's the time to actively prepare for the months ahead, particularly those communities
in bushfire and cyclone-prone regions.
As we all know, Australia's weather can change quickly, so it's important to follow advice
from emergency services on what to do before, during and after severe weather.
Stay up to date with the latest forecast and warnings on the Bureau's website.
And keep an eye out for our weather update videos throughout the coming months.