RAINFALL BECOMING EXTENSIVE OVER THE COMING WEEK FOR THE NATION

A more detailed look at the rainfall breakdown from each model and an explainer on each of the approaches to next week.


Rainfall for the next 10 days - Valid Wednesday 16th of June 2021

This is a blend of all the data that is available as of Wednesday morning.

The Euro Model is suggesting some reasonable falls with the low moving through the southeast over the coming with a deepening surface low moving over the southeast and off the NSW coast. A new piggy back feature will bring another burst of rain and strong winds to SA with cold air.


Next week as the low resolves over the Tasman Sea, another wave of low pressure will start to develop offshore WA and this will likely link in with large scale moisture profile in the Indian Ocean bringing in widespread falls from northwest through to the southeast.


The rainfall numbers at this stage will be heaviest over the northwest of the nation then thin out a bit before reorganising along the lifting mechanism over the southeast of the nation, with another round of widespread moderate rainfall.


Showers over the southwest of the nation will return from Sunday through next week with reasonable falls expected. There could be heavy falls over parts of southeast NSW with a low offshore.


Euro Surface Pressure Pattern with rainfall distribution- Next 10 days - Valid Wednesday 16th of June 2021

Euro Rainfall next 10 days - Valid Wednesday 16th of June 2021

Showing that large rainband over WA, thinning out perhaps over SA a little before emerging over the south and east with some moderate to heavy falls along the path next week. Rainfall could be heavy at times over the south and southeast of Australia with a low pressure system.

GFS is similar in it's approach with a large amount of moisture being drawn across the country next week and being dragged south and southeast over SA but more pronounced over QLD and NSW.


Once we see the low resolve over the Tasman Sea, a large cloudband will develop from the northwest through to the southeast of the nation with widespread falls, moderate to heavy rainfall is possible along its path through to the southeast.


Further frontal weather and further injections of moisture will made into the jet stream, meaning further rainfall is possible through the coming week beyond this, with the potential for widespread falls.


Precipitable Water Values - Next two weeks - GFS 18z run Valid Wednesday 16th of June 2021

High levels of moisture can be seen drawn across the country next week with a strong cold front over WA acting as a pulling mechanism for the jet stream to fall south in response, bringing that large pool of convective weather offshore, towards WA and developing a rainband through the region. That rainband then advances and picks up forward speed as it is dragged south into the central and eastern inland later in the period. Note further wet weather potential following this, just like the Euro model.

GFS Rainfall - Next 10 days - Valid Wednesday 16th of June 2021.

Very similar rainfall spread from this model in line with Euro.

The secondary models are also looking somewhat in line with the primary models. They are all pinging that moisture signal racing down from the northwest to the southeast ahead and with a long wave trough passing through the south of the nation. There will be kinks and weakening/strengthening of the rain band along it's journey through the nation, exactly where that occurs remains to be seen.


KMA Rainfall for the next 10 days - Valid Wednesday June 16th 2021

This model also showing that rain band developing over the northwest and spreading throughout the nation, a little more rainfall being picked up over QLD in this particular model which remains to be seen. Good agreement on healthy rainfall totals over SA through VIC and NSW with the main frontal passage next week. Has light to moderate falls this week with the low pushing off to the east, though heavy falls are being analysed over the southeast of VIC, again remains to be seen. Good rainfall expected to return to SWLD of WA with moderate falls extending inland to the Wheatbelt, that is seasonal for this time of year.

Note that this model is in agreeance with the Euro and GFS in bringing more rainfall into the nation following the major rainfall event spread nationwide next week.

ACCESS-G Rainfall for the next 10 days - Valid Wednesday June 16th 2021

The model is a little thinner in the rain band moving across the nation next week and keeps it disconnected from the westerly wind belt developing over the southern parts of the nation, meaning under such circumstances, this would bode better rainfall wise for QLD with a large cloud band moving over the southern and southwest areas of the state. Still reasonable rainfall expected through the southern parts of the nation with regular frontal weather. More wet weather is being picked up by this model for the period following as per the primary modelling used.

CMC Rainfall for the next 10 days - Valid Wednesday June 16th 2021

The Canadian Model is showing some reasonable precip with the initial system this week in to the weekend over the southeast with heavy falls for far eastern VIC and southern NSW along the coast with the low pressure. A deepening wave of low pressure offshore the west coast looks likely to connect with modest moisture levels and bring a rainband through SA and then into the eastern states as per GFS (these models are related). The coverage of rainfall is not as heavy nor as widespread which is going against the grain.

As you can see there are very good signals for rainfall over the coming 10 days. This will likely produce half to one month's worth of rainfall over parts of the nation. Need more specific forecasting, email me at karllijnders@weathermatters.org for further details.


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