Hello and welcome to the May update of the sugarcane rainfall outlook for the southern Gold
Coast and New South Wales Sugarcane District. In this presentation we'll be covering recent
rainfall amounts recorded so far in May, then the forecast rainfall over the short term. We'll then
look at the June and July rainfall outlooks in detail before a short summary of the longer term
winter rainfall outlooks and climate drivers. Since the start of May we've seen mixed results
regarding rainfall across the region. Totals of 100 to 120 millimetres so far through the Gold
Coast and Northern Rivers regions have reached, or in some cases already exceeded median May totals,
however rainfall totals of around 20 to 50 millimetres further south from Evans head to
Grafton are well below average, sitting at roughly 40 to 60% of May median rainfall for the region.
In the short term a strong cold front will cross New South Wales during Friday with a
low expected to form well away from the northeast coast of NSW later in the day.
This will bring windy conditions but little in the way of rainfall as we can see in the
rainfall graphic for Friday above, with showers confined largely south of around Coffs Harbour.
A colder air mass in the wake of the front will see minimum and maximum temperatures drop two
to four degrees below average for May over the weekend and early next week, with temperatures
gradually warming from mid- next week. Here we have the chance of exceeding 25 millimetres of
rainfall over the next fortnight broken down into week-long periods. You can access these maps on
the link above. I have selected 25 millimetres to display here and on the website there are a
number of rainfall thresholds available between one millimetre to 700 millimetres to choose from.
On the left, week one covers from the 28th of May to the 3rd of June and week 2 from the 4th
of June to the 10th of June on the right. Over the Gold Coast region we're looking at a less than
10% chance of exceeding 25 millimetres in each week. Further south there's a 10 to 25% chance
of exceeding 25 millimetres over New South Wales with the odds increasing to 25 to 50% about the
Ballina Coast in week two. Into the whole of June Outlook and an average to slightly below average
chance of exceeding the June median rainfall is predicted, with the model skill at this time of
year moderate getting it correct typically 50 to 65% of the time. For further information
including point location forecasts check out the Bureau Climate Outlooks page on the link above.
This translates into a lower chance of seeing rainfall close to the historical
median for the month, as we can see from the slightly lower values in the 50% chance of
at least chart on the left compared with the historical median map on the right.
Expanding further on the possible June rainfall totals here with the high chance on the left
the 75% chance of exceeding, or three out of four times we can expect to see at least this
much through the month of June, and the lower chance totals on the right, the 25% chance or
one out of four times we would see these totals exceeded during June. Moving on to the month of
July and a neutral to slightly wetter signature is evident in the rainfall Outlook that month
with average to slightly above average odds of 40 to 65% of exceeding the July median rainfall.
The model skill during July is typically correct 55 to 65% of the time.
This translates into about a roughly equal chance of seeing rainfall close to or slightly higher
than the historical median for the month as we can see from the slightly higher values in the
50% chance of at least chart on the left compared with the historical median map on the right.
Expanding on the possible July rainfall totals here with the high chance on the left the 75%
chance of receiving at least, and the lower chance totals on the right the 25% chance.
A quick snapshot of the rainfall outlook for Winter months through June to August as a
whole and we see a neutral signal around 40 to 60% percent of exceeding the median rainfall. Across
Winter the modelling is typically correct 65 to 75% of the time through this forecast period.
So what's driving this? We are currently in an El Niño Watch with a 50% chance of an El Niño
forming later this year, around double the normal likelihood. In recent months we have
observed eastern tropical Pacific waters warming, but we've seen little atmospheric response yet.
All International climate models indicate it is very likely Pacific ocean temperatures
will reach El Niño thresholds during the Winter, however an atmospheric
response is also required for an El Niño to be declared by the Bureau. El Niño is normally
associated with lower than average winter and spring rainfall over eastern Australia
This translates into an about equal chance of seeing rainfall close to the historical
median for the Winter as we can see from the similar values between the 50% chance of at
least chart on the left compared with the historical median map on the right.
That's it for this update, as always check the latest forecasts and warnings on the
bureau's website or the BOM Weather App, and be sure to send any feedback through
to agriculture@bom.gov.au, we'd love to hear from you. See you next Outlook, thanks for listening