Welcome to the Bureau of Meteorology Severe Weather Outlook for October 2019
to April 2020. 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, elevated bushfire potential particularly in the east,
fewer than average tropical cyclones, a lower risk of widespread flooding, and a
near normal outlook for severe thunderstorms. Large parts of Australia
are extremely dry as we head into the warm months, especially in the east
where some areas have seen very little rain now for three years. This year
our nations January to September rainfall was the fourth lowest on record
and the lowest since 1965. 2019 has also been exceptionally warm with our daytime
temperatures so far this year tracking as the highest on record. We expect the
warm and dry trend to continue for the remainder of the year, this increases the
risk of severe weather in some regions but reduces it in others. Let's step
through the outlook. Heatwaves are Australia's most deadly severe weather.
Warm nights after hot days give our bodies a little chance to cool down and
heat stress becomes a real risk to human health. Heatwaves also have a
significant impact on our economy with agriculture, energy management,
infrastructure, and other industry all affected. This summer there's a higher
chance of extreme heat developing across our inland with soils so dry and an
outlook for clearer skies. This raises the risk of heatwaves for much of
southern and eastern Australia when winds push this heat towards the coast.
Just like last year it's been an early start to the fire season for many, with
bushfires already in Queensland and New South Wales during August and September.
Through the remainder of the fire season the dry landscape in the east and
southwest Western Australia means that any warm and windy weather will increase
the fire risk, particularly along the coast and through elevated areas.
Australia sees around 11 tropical cyclones on average each year with four
crossing our coast. This year were expecting fewer tropical cyclones than
average. This is usually indicated when we see higher than normal air pressure
across northern Australia which has been the case over recent months, remember
though Australia has never had a season without the coastal crossing, and
cyclones are not evenly spread throughout the season. What the seasonal
outlook can't predict is the size, intensity or exact location of where any
one cyclone may form. This means communities' right across northern
Australia need to stay prepared throughout the cyclone season. The chance
of widespread Riverine flooding is reduced in the months ahead.
When the land is dry and rivers are low rain first soaks into soils before
filling rivers. This explains the outlook for lower than average flows through
rivers in many catchments. And whilst Indian Ocean patterns suggest a later
than normal arrival for the first rains of this year's northern wet season.
localised major flooding can occur in any northern wet season. This is
especially the case with slow-moving tropical lows which can cause
widespread rainfall and dangerous flooding, even in areas that have been
previously dry. We saw this last wet season with historic floods across
northern and central Queensland during January and February.
Some places received more than two meters of rain in just 10 days as the
monsoon trough and a slow-moving tropical low set in. Severe thunderstorms
are dangerous because of their potential for flash flooding, large hail damaging
winds and sometimes tornadoes. Severe thunderstorms are more common during the
warmer months, particularly in northern New South Wales, southern Queensland
inland Western Australia and across the Tropical North. Across southern Australia
the risk of heavy rain with severe thunderstorms increases when humidity
and moisture extend across the continent from tropical weather systems.
Thunderstorm asthma can also be triggered by severe
thunderstorms especially from October to December when pollen levels are highest.
So with the fire season already underway and cyclone season just around the
corner, now's the time to actively prepare for the months ahead
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 forecasts and warnings on the
Bureau's website, and keep an eye out for our weather update videos throughout the
coming months.