Over the next week the far southwest, and much of the southeast are set for the highest rainfall totals.
That wasn't a misprint! Yes, the drought affected southeast is likely to be one of the areas that sees the most rain over the next week!
RAIN SYSTEM ONE
The remains of a big rain system in the west late last week/into the weekend is crossing the Bight on Monday.
It has lost it's connection to tropical moisture from the Indian Ocean (that enabled rain to fall from the Pilbara right through to the south coast), but it will pick up some moisture from the warm waters to our east.
Once again, the low pressure fails to connect with this new moisture source when crossing the dry parts of the southeast, with the rainfalls decreasing away from the coast - and then increasing as an upper level system crosses NSW (to visualise this, see the day by day rainfall maps here).
That's just system one - there are better things on the horizon.
RAIN SYSTEM TWO
The next big system affects Western Australia from early to mid week. Again, this has the winning combination of great instability working with tropical moisture from the Indian Ocean, to produce widespread rain from the Pilbara through to the south. This one is heaviest in the southwest corner, but there are still decent falls inland.
Then things get interesting: the weather pattern won't shunt this one southwards as it crosses the southeast, nor will it lose its connection to tropical moisture - and this is incredibly good news for the southeast.
We haven't seen a projected rainfall map with 10 to 25 mm across the vast majority of the southeast for a long time, especially not one that also has pockets with 25 to 50 mm. This does include the system (rain system one) on Tuesday/Wednesday, but that's just a small part - the real rain (from rain system two) arrives on Thursday/Friday and continues over the weekend and into early next week.
Why is this one different?
Instead of high pressure dominating the southeast, deflecting or weakening low pressure, this one has no high pressure to worry about, in fact, the high is elsewhere, and will let a cut-off low slowly meander across the southeast.
'Cut-off' meaning that it is separated from the fast moving westerly winds to our south that whisk these weather systems away before we can get much from them. This one is exactly the opposite - it's the kind that brings steady, soaking rain over a period of a few days.
This one is also different because there's a connection to tropical moisture. Australia has had good access to tropical moisture for a long time now, and finally that moisture will interact with low pressure - as it actually crosses the southeast.
It all kicks off on Thursday/Friday this week, and I'll have the latest updates here.
