Importance of Natural Resources

Climate and Water Outlook, issued 31 October 2019

Welcome to the Climate and Water Outlook for
November 2019 to January 2020. November and December are likely to be drier
than average for almost all of Australia, however the dry signal looks likely to ease
in the new year. But first, let’s look at recent conditions. October has been drier than average for large
parts of Australia, continuing the long-term dry spell. Mildura Airport had no rain in October for
only the second time since records began in 1946. Central Queensland had some rain in late October
– with several locations receiving more than 30mm. Daytime temperatures during October were very
much above average for much of Australia. A burst of heat on the 24th of October brought
maximum temperatures more than 12 degrees above average to parts of the southeast. Mount Gambier Airport recorded 34.4—their
hottest October day on record. Soils have dried further this month in many
areas; the result of low rainfall and high temperatures during October. Fires, raised dust and extreme winds affected
several parts of the country in eastern Australia, bringing smoke haze and reduced visibility. Water storages in southern Australia are generally
at the end of their filling season. While some are now a little higher, many are
much lower than they were 12 months ago. So, what will influence our climate in the
coming months? A very strong positive Indian Ocean Dipole
is likely to continue well into December— several weeks later than normal. The last time we saw an IOD this strong was
back in 1997. A positive Indian Ocean Dipole typically means a hotter and
drier than average spring over central and southern Australia. In November, we’re also likely to be affected
by a negative Southern Annular Mode, or negative SAM. At this time of year, a negative SAM means
an increased risk of hot and dry conditions for eastern Australia, but cooler and wetter
in western Tasmania. Both the positive IOD and the negative SAM
patterns are likely to break down in summer. With a record-late withdrawal of the Indian
monsoon, the movement of the monsoon trough into the southern hemisphere is also likely
to be delayed. For northern Australia this may mean a late
start to the summer monsoon. So, what does this mean for the outlooks? November and December are likely to be drier
than usual for almost all of Australia, particularly in the east, but January may see an easing
of the dry signal. Australia’s tropical cyclone season typically
begins in November. This year’s outlook suggests fewer-than-average
tropical cyclones are likely to form in our region. But Australia has always had at least one
tropical cyclone cross the coast each season, so those who live in areas affected by tropical
cyclones should be prepared. Turning to streamflow, mostly low flows are
expected to continue across much of Australia for October to December. Near-median and high flows are likely in some
locations that had rainfall in earlier months. The temperature outlook suggests that days
are likely to remain warmer than average across much of mainland Australia. This means there’s an increased chance of
heatwaves, and windy days will see elevated fire danger,
so please take care. Warmer nights are very likely for large parts
of the country, also contributing to the increased heatwave risk. So in summary, November to January is likely
to see: many areas drier than average; a late arrival of the first northern rains; higher-than-average temperatures; low streamflows at most locations; and an increased risk of heatwaves and bushfire. Thanks for joining us, you can find out more
about the outlooks on our website. We’ll see you next time.

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