ANOTHER LOOK AT THE MOISTURE AND POTENTIAL CLOUD BANDS NEXT WEEK.

A winter time set up has been covered off repeatedly in the national and state based updates, this is now a focused look at the moisture spreading through the nation next week, bringing rainfall chances up.


But will they connect with frontal systems?


Over the course of the next 5-6 days, I will be posting an update morning and evening (time pressures pending on the evening update with the wild weather potential over the east and southwest in coming days) but keep checking back in.


Lets take a look at where we stand today.


The latest model split surrounding moisture movement during this period and the scale of how far east and south the moisture comes.

Potential Rainfall for the period 13-19th of July in association with the cloud bands and frontal weather racing through the southern half of the nation based off the latest data sets. This the mean of all of those models this morning from the 9 agencies assessed. Valid Wednesday 7th of July 2021




GFS 18z Precipitable Water Values - Valid Wednesday 7th of July 2021.

You are looking for the green and more wanted blue and purple shadings coming from the northwest and extending deep into the southern and eastern inland, linking up with cold fronts and troughs. You can see that occurring next week and the week after. I am focusing now on the potential next week as there is evidence that may be a decent cloud band.

Euro 12z Simulated Water Vapour in the upper atmosphere for the next 10 days - Valid Wednesday 7th of July 2021.

Note the extensive surge of moisture from the Indian Ocean streaming into the deep westerly wind belt next week and beyond. This will see a lot of cloud form, not necessarily widespread inland rainfall, at this stage, however this could change as we get closer to the frontal weather next week. The moisture profile is very promising as we move into the back half of July and into early August. You can read more about that in the climate section of the blog (head to the blog homepage and click on the menu to find the Climate Section).

Euro 12z Simulated IR Satellite for the next 10 days - Valid Wednesday 7th of July 2021.

The moisture is present but we need lifting mechanisms to produce more cloud bands. Note the deeper moisture being lifted by a trough over the eastern inland and deepening into a low, that needs to occur within the moisture plume over WA and SA during the outlook period for more widespread and productive rainfall to develop, which is not impossible and again, a system may emerge in the coming weeks where the ingredients, which are there, all come together.

Euro 12z Ensemble Rainfall for the next 15 days - Valid Wednesday 7th of July 2021.

Looking at the broader data sets to display the chances of rainfall coming from the northwest through southeast now, and you can see the trend for the heavier rainfall over coastal areas but numbers are increasing for inland WA and into SA. This is the least likely out of the model sets in my opinion based on the current trend in moisture and frontal weather being observed in the medium term.

Euro 12z Control member - single data set - Rainfall for the next 15 days - Valid Wednesday 7th of July 2021.

Control member shows a moisture infeed from the northwest later in the run, but curiously allows the ridge to win out over much of northern SA which again I am not buying at this time. But important to show all solutions on the table.

CMC 12z Ensemble Rainfall for the next 15 days - Valid Wednesday 7th of July 2021.

This is the model which is probably expressing the correct outcome across the southern and west parts of the nation for next week with more moisture being dragged in (which Euro does see as you can see above in the simulated parameters) and the triggers being frontal weather using that moisture to create more windy rainfall for southern parts of Australia for a number of days across a range of fast moving shortwaves and troughs.

GFS 18z Ensemble Rainfall for the next 16 days - Valid Wednesday 7th of July 2021.

Similar to CMC with widespread rainfall coming from the northwest through to the southeast with a series of fronts lifting the moisture streaming out of the northwest Indian Ocean, bulking up the rainfall with each frontal passage. Again I think this is the probably closer to the truth over the coming 2 weeks.

All models are seeing the correct rainfall spread over the next 2 weeks, it is now just a matter of ironing out each event as they come through.


The first cloud band on Tuesday through Wednesday over the southern parts of the nation could be rather productive, especially through SA and into VIC.


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