I'm Angus here at the Bureau of Meteorology, today is Wednesday, the 23rd of July.
And let's get into it, starting with a look at the west of the country where we actually see two distinct weather events today. A cold front to the south-west and then further north, a low pressure area which is a bit closer to those warm waters of the Indian Ocean. Throughout today, we will see these two weather events get closer towards each other and eventually merge into one. The low pressure area gets a bit washed out, but the moisture, which is wrapped around it-that gets swept in with this cold front and by the end of today, by tonight, it will be raining right across the west coast with some patchy falls over inland areas as well.
Initially, the heaviest rain will be right along the west coast, including in the vicinity of Perth, where we could see 50 mm sort of anywhere along the coast from Geraldton down to the far south-west. Inland areas, including the Wheatbelt, will get significantly less rain today, most places less than 10 mm and some places nothing at all.
Tomorrow, this band of wet weather will pull eastwards, spreading throughout Western Australia in the morning. That will hit pretty much all regions from the Pilbara, through the interior, down to the south coast and into the Nullarbor as well. After lunch on Thursday, we'll see that rain push across the state border into western parts of South Australia and potentially into the Territory as well.
As that's happening, this band of rain is coalescing and solidifying, becoming a really solid band of wet weather. This rain is much heavier and more extensive than the last several cold fronts, which have looked pretty similar on our map.
So why is this one bringing so much more rainfall? To answer that question, we're going to look at this map here, which is a forecast for precipitable water. Another way to say that it's a forecast for moisture content in the atmosphere. Currently across Australia it's quite dry over the mainland, but we see much more moisture content in the far north over those warm tropical waters. And that's shown by the blues and the dark greens on this map here.
As I play through the map now and we see this cold front moving from the south-west, watch how it drags down some of that high moisture air across Western Australia and then into central parts of the country. We see this link from the Indian Ocean right down to South Australia, where that moisture is just fueling the rain. This is Friday morning, but we keep going forward. We see another surge of that high moisture air from the north, this time over the Gulf of Carpentaria, getting dragged down across the eastern states. And that will continue to fuel the wet weather across the east as we move through the weekend. That's the main reason why the rain becomes so extensive.
We're now looking at Thursday's rain, building on what we saw out west on Wednesday, and we see how much more widespread it gets. A few yellows and oranges working on to the map too, showing some slightly heavier falls. But Thursday's still not the main day for rainfall this week.
Now we head to Friday and we see this band move eastwards, bringing extensive rain across South Australia through much of the Territory into western parts of New South Wales, south-western parts of Queensland and western parts of Victoria. By the end of the day Friday, the rain has moved about halfway through these eastern states.
Now again, we'll build on the rain we've been mapping already and add in the rain we're expecting on Friday. Now take a look at this tri-state border corner area-eastern South Australia, western Victoria and south-western New South Wales. This is an area which has experienced severe rainfall deficiencies throughout this year and most of last year as well. It really needs rain in this part of the country and they're getting a significant dose as well.
Most of these areas could see between 20 and 30 mm of rain on Thursday night or Friday morning, and a few spots will likely get more. While that is good news for the area, that is not enough rainfall to catch up with how much they've been missing over the past 18 months. This is one good weather event, but it would take many good weather events to catch up those rainfall deficits. So it's a step in the right direction, but it is not the end of the dry conditions, unfortunately.
Let's go forward through the last day that we'll check out at the moment. This is now Saturday into the weekend. More rain spreads through Victoria, especially in the morning. Then we have a band of rain extending northwards up through New South Wales and Queensland. Even though the falls here won't be too unusual for the regions, it is a bit unusual for this time of year because it is the dry season up here, but they will be seeing some rainfall.
As this whole system starts to pull away from the country, the backside of it will wrap around bringing some cold winds and an influx or return of showers across South Australia, Victoria and parts of New South Wales, even once that main band has pulled through. So you might get a nice little top up of wet weather for the next couple of days, even after the rain has cleared.
This is the last look at this map. This is now showing the total rainfall from Wednesday to Saturday, that four day period, and really just highlighting how extensive it is, how many areas are getting above 25 mm. And the reds show places that could get 50 mm, including parts of the Queensland/New South Wales border, the Victoria Ranges, northern Tasmania and the islands and peninsulas around southern South Australia.
I've talked a lot about the rain, but there will also be an element of strong winds as this weather system rolls through. Just quickly play through this map over the course of a few days. Look for those reds and purples to really flare up at times across central parts of Australia. Could be seeing some very strong winds through South Australia and then eventually into the eastern states as well, and that may result in some Severe Weather Warnings getting issued.
So over the next few days, do stay up to date with your forecast information available on the Bureau's website and app. And thanks for watching.
