A few showers are possible this weekend about the coast with a southeasterly change moving north, with some limited moisture being drawn through the inland via these winds.
It really is all about next week, after a fine and warmer day state wide on Monday, the moisture from the easterly winds over QLD and NSW, projects west and will pool ahead of a trough that is moving through SA on Tuesday.
This will give rise to scattered showers and thunderstorms throughout the states western inland, the far west likely dry for now. Then mid to late week, wet with periods of rain and thunderstorms moving through.
Lets take a look
Rainfall next 10 days
I am going to keep this chart broad for today and let the models work it out over the coming 36hrs as there will be some madness going on in terms of your number varying from data set to data set. Largely unchanged from overnight and this morning, the rainfall heaviest along and west of the GDR with flood risks over the southeast inland west of the divide and possible about some of the southern plains as well. The rainfall could net upwards of 100mm in some locations in the coming 10 days over the inland, but as I keep repeating your number will vary with the uneven distribution of rainfall in these convective set ups.
Euro 00z - Surface Pressure Pattern and Rainfall Distribution - Next 10 days
Modelling is largely unchanged from this morning which in a sense is good news for forecasting, not great for those who don't want the rain, who do want the rainfall. A trough over in WA is expected to deepen with a decent slab of moisture being drawn into this feature triggering widespread showers and a few thunderstorms Sunday. In the east onshore winds are still expected to push on the NSW coast with a slow moving boundary that will stall out over SEQ during Monday. Light falls with that and a noticeable uptick in humidity. A surface trough over the inland portions of QLD will kick off a few showers and thunderstorms along it's axis during Monday and Tuesday before that moisture is drawn south and lifted by a stronger trough passing out of SA later Tuesday. That will fuel more robust showers and thunderstorms for NSW and VIC with moderate to heavy falls, there is a risk some storms could be severe Tuesday with heavy rainfall and damaging winds a threat. Then wet through the southeast and eastern inland for most of next week, another change to roll through WA holds better rainfall potential for SA for the poor old crops hanging on for dear life and the tropics, suppressed but will turn more stormy once we get the upper high out the way later next week.
Euro 00z - Precipitable Water Anomalies - Next 10 days
The process to override the drier air takes place this weekend with a good shot of moisture coming in from the Indian Ocean, which you can see on the satellite imagery, denoted by the high and middle level cloud, that will be drawn into a trough over the SWLD producing showers and storms from Sunday. Another shot of moisture will be developing via easterly winds in QLD and NSW with that moisture expected to travel west through the eastern interior, then being drawn south into NSW and VIC. This moisture will then be merging with the remnants of what comes out of WA to produce a large area of above average moisture content in the atmosphere, leading to widespread rainfall. Then for the remainder of the period, keeping watch of moisture being drawn in via the mid latitude westerly winds over the Indian Ocean into a follow up feature over WA, that holds better potential for SA in the end of this period.
Euro 00z - Rainfall Accumulation - Next 10 days
Rainfall distribution as mentioned, uneven through the eastern states, that is in terms of totals you will see. It will come down to thunderstorms and this is why I refer to convective setups lead to uneven distribution of rainfall. So keep that in mind looking at ALL rainfall products out there. The wettest weather clearly the southeast and eastern inland of NSW and VIC where flooding is a risk. The east coast should see an increase in shower coverage leading to welcome falls. Light falls for now over SA, but numbers will likely tick up IF the weather out west can be in phase over the region, the second feature offering the most hope. The west of the nation, looking damp over the SWLD with periods of rain and thunderstorms from time to time in the early part of the period but the follow up system could drop a lot of rainfall if the moisture can get in front of the low and front slowly moving in offshore. The tropical north, isolated showers and thunderstorms about, you know the drill, down the road could get 1 inch of rain in 20 minutes and 2km away get a nice outflow breeze from it with not a drop.
A closer look - heavy rainfall is increasing in coverage.
GFS for comparison for the coming 2 weeks.
More details coming up on Saturday morning.