Forward Projections
Forward Projections:
BOM declares La Nina alert, with 70pc chance of forming in 2020
The odds of a La Nina in the coming months have improved to a 70 per cent chance — roughly three times the normal likelihood — and it’s not the only climate driver that could potentially favour wet conditions heading into spring.
Key points:
BOM says the chances of a La Nina forming in the coming months is three times more likely than normal
La Ninas are associated with wet conditions for Australia but sometimes don’t result in widespread rain
How it plays out will depend on the other climate drivers and individual weather systems
Bureau of Meteorology (BOM) climatologist Naomi Benger said La Nina could mean a few different things for the Australian region.
“One of them is enhanced rainfall for central, eastern and northern Australia,” she said.
“So while some areas might welcome that bit of extra rain if they’ve been in drought, it can lead to an elevated risk of flooding.”
La Nina events are also associated with heightened risk of cyclones as well as cool daytime temperatures.
“There is generally more cloud and more soil moisture, which means the daytime temperatures could be a little bit lower on average,” Dr Benger said.
La Ninas are typically wet, but …
Weather nerds with good memories will recall a La Nina was declared in 2017 and, rather than bringing widespread rains, it was the beginning of the latest drought.
Dr Benger said that La Nina did not last long enough for the impacts to really manifest.
“The last significant La Nina event was in 2010-11, and that was Australia’s wettest two-year period on record,” she said.
Many will remember that summer for widespread flooding along the east coast, including the worst floods in Brisbane since 1974.
So are we looking at a 2017-18 or a 2010-11 kind of event?
Dr Benger said it was difficult to say at this stage, and the BOM’s announcement did not guarantee Australia will reach La Nina thresholds this year.
“At the moment there’s a 70 per cent chance of it developing, but really how it manifests will depend on the other climate drivers as well.”
The other climate drivers
Over the past few years, the positive phase of the Indian Ocean Dipole (IOD) has been dominant, bringing dry conditions to eastern Australia.
This year, however, it looks like that could change.
“The IOD has been quite tricky this autumn-winter period to predict, but at the moment, three of the six models that the BOM surveys are indicating that a negative IOD could develop during spring,” Dr Benger said.
A negative IOD favours wetter-than-average conditions for Australia — but some of the models are indicating a more neutral IOD in the coming months.
“We are certainly not as confident in that as we are with the La Nina,” Dr Benger said.
But at least it currently looks unlikely we will be facing another strong positive IOD.
Then, of course, there are other drivers, like the Southern Annular Mode (SAM).
Dr Benger said while the SAM operated on a shorter time period, it would affect how far north or south frontal systems to the south of Australia moved and how far south rain-bearing systems came along the east coast.
“So that will also play into when and where we get rainfall.”
Speaking of cold fronts, a series of fronts and troughs is expected to bring strong winds, rain, hail, snow and below-average temperatures for the south-east of the country over the coming days.
Notes
The ENSO Outlook is currently INACTIVE. This means there is little sign of El Niño or La Niña developing in the coming months. The criteria will continue to be assessed each fortnight. The status will be upgraded when the criteria and expert assessment indicate an increase in the chance of an ENSO (El Niño or La Niña) event developing.
Further information on the current status of ENSO can be found in the ENSO Wrap-Up.
Details: ENSO Wrap-Up
Always monitor our Facebook page and listen on air on the FM band 101.5 Mhz or listen live via our website above.
Current Fires in our listening area & Warnings
The Rural Fire Service Queensland advises you to:
- Action your Bushfire Survival Plan now.
- Monitor the fire and weather situation through your local radio station, www.ruralfire.qld.gov.au and www.bom.gov.au.
- Call 000 (Triple Zero) in an emergency.
For information on preparing for bushfires go to www.ruralfire.qld.gov.au.
.
Fire Season 2019 – Queensland bushfire season expected to last longer
Queensland emergency services are bracing for what is expected to be a long and “very active” fire season, with weather experts saying the outlook is “not a good news story”.
Significant fire activity expected from Rockhampton to the NSW border
Dry fire fighting techniques will be used in areas such as the Granite Belt and Darling Downs
About 33,000 volunteer firefighters are on call across the state
The Bushfire and Natural Hazards CRC released its bushfire outlook joined by fire representatives from across the country — who warned communities to be prepared.
Queensland Fire and Emergency Services (QFES) Deputy Commissioner Mark Roche said Queensland had already started its fire season, with several fires coming close to homes and killing wildlife in the south-east last week.
The bushfire season has started early and we expect it will go later as well.
Over the last couple of weeks we’ve seen some significant fires, we note this report in the bushfire outlook and we believe we are very well prepared.
But we need the local community, we need the local government to be prepared and support us side by side.
Bushfire Outlook 2019 (Supplied: Bushfire and Natural Hazard CRC)
What is a catastrophic fire?
A catastrophic fire danger rating is as bad as it gets
While some homes may survive a severe or extreme fire if you’re well prepared, the Country Fire Authority says no homes are designed to withstand catastrophic conditions
If a fire starts and takes hold during catastrophic fire conditions, the weather bureau says it will be “extremely difficult to control” and take “significant firefighting resources”
This is the first time a catastrophic fire warning has been issued in Queensland
When these warnings are issued, your only safe option is to leave the area early
The catastrophic category was added following the 2009 Black Saturday fires in Victoria
