The mid-May event is building and the timing couldn't be better aligned.

追加: 2026-05-11

[00:00:00]Good day everyone. Monday, May 11th.

[00:00:02]This is a weekly update. Uh we've got an upper trough forming through the northern interior of the Northern Territory and up through the Kimbley.

[00:00:08]That's shooting some cloud and upper level instability through, you know, the northern parts of the Northern Territory through the Gulf country down into sort of central Queensland. At the moment, quite light activity. If you remember from last week's update, we saw that a lot of those rainfall bands were going to be like this, just these small thin corridors moving in through the northwest of Queensland. This will slowly increase in in distribution.

[00:00:29]Won't say intensity, but this sort of activity coming down through the Arafuran Gulf should shift down further south into the channel country, northeast partial districts and eventually down into southeast and South Australia and parts of Western New South Wales, Western Victoria. What will come after that though and what will sort of enhance rainfall moving forward in from midmon is we've got this cloud band coming in from out near the Kokus Islands. Once we look at it on the water vapor, you'll see why it's so important.

[00:00:53]And you'll see the upper level pattern that's going to influence this major weather outbreak over the next week or so. Also to the south, there's a frontal system which is helping to draw that that cloud band in from the Indian Ocean as well. Uh this should bring some some showers and patchy storms to part of the southwest corner of Western Australia.

[00:01:09]Not as wet as I had had anticipated for the west this this next week, but um we're definitely going to see an increase in moisture moving forward. And this these cloud bands are a good telltale to see that this this larger cycle of midmay is now well and truly developing. So this is the water vapor.

[00:01:24]You can see there's an upper trough starting to form up through the north Kimbley that's sharing that cloud and moisture in through the Arafura Sea down through the Gulf country into northern inland parts of Queensland. This upper trough will amplify to the northwest over the next few days and it'll link up with this uh this trough moving in from the Indian Ocean and we'll see this deeper layer of moisture coming off this sort of a tropical low type signal being sheared right across the Indian Ocean into Western Australia and that'll help funnel this northwest cloud band that we're looking at over the next week or so that builds through the through the northwest through the interior into parts of South Australia, New South Wales, Victoria, Tasmania and southern and western Queensland. and and as this major feature builds and moves across the country, this is what should enhance that east coast uh trough, possibly east coast low into the last week of May. So, this is definitely the patterns we're looking for, which is good to see, and it should be building from around midmon. Um, what's interesting, too, is as this major system develops, we're starting to see the next coronal holes almost earth facing. So, if we go to the coronal hole, uh, solar imagery, this is a coronal hole here. Uh, the sun takes about 28 days to rotate. So if you divide that by four, it's about 7 days per quarter and we're about halfway through that quarter there. So about 3 days, 3 or 4 days, this this corona hole should be earth facing. In 3 or 4 days should be around the 15th and then that major weather period runs from around you know the wetest periods from the 18th till 22nd. So that that that aligns with this being earth facing and then there's usually a couple of days lag time for that solar wind to in affect the atmosphere and then there's a a laging effect where it enhances the weather system. So that'll see um weather become enhanced from around midmon extending into week four. So this is exactly what we need to see. Timing is perfect. And corona holes tend to lead to those longer duration weather events, more widespread rather than uh those, you know, overnight southern intensification periods of weather system. So this is really good to see in terms of what we're looking for large scale weather patterns over the next uh week or so across the country.

[00:03:26]This is the weekly preip anomalies. So again, these aren't a rainfall forecast and it's important that we uh understand how we interpret this model. If this shows you're getting, you know, 10 to 20 m above average, that's the average for that area. So it doesn't mean you're going to get 20 or 30 ms. It means if your average is 5 ms, you might see 25 at best. If you're uh you know down through the central west and your average for May is 25 ms and it's showing white, there's a good chance you'll get close to average rainfall with there's there's a positive and negative anomaly either side of say the central west of New South Wales. So there's a good chance that that rainfall would be closer to the average than above. So again, if you're only getting one weather system per month, which is generally the case for a lot of these re regions through the southern interior, um if your average is about 25 ms, there's a good chance that you will see that within the next system. However, we know that in the last 2 weeks, we saw a frontal system come through here with a bit of a northwest component like we're about to see. And a lot of these areas saw anywhere from 10 to 50 ms. So, in saying that, on top of what you've already had, you might see the the average rainfall yet again. So, you could see a well above average month, especially for western parts of the state and the lower western if this simulation comes off. Uh, and that's how you again how you look at this model. In the west, this isn't showing no rain.

[00:04:52]It's showing there's a chance that at this time of year for these districts, you might see 5 to 10 ms below the average for that region. So if the the Geraldton region for example has a 20 mil average, you might see 5 to 10 ms in this particular week um at best according to this model and so on and so forth. So that's how you interpret that.

[00:05:12]These totals up in the north through the Kimbley in Northern Territory. This time of year the averages are quite low.

[00:05:17]They're about 5 or 10 ms. So to see 5 or 10 ms above average, you're still only going to see pretty light rainfall in in all honesty how that works. Same along the Queensland coast generally average is slightly below for this time of year.

[00:05:29]So what's important again with this model is we're looking at the direction of the the the rainfall. So any anomalies along the east coast this time of year are traditionally to do with uh southeast trade showers. So these are the exposed coastlines that generally do the best in these situations. You'll notice that the Sydney metro Ilawa does well when there's a when there's a ridge in the south here. Also the northern rivers up to the Fraser coast where that exposed coastline is there. They do quite well in the southeast trade. Same with around that Mai with Sundays in the southeast trade winds. You can see the winds come straight up and hit the islands. Then again north of Townsville along that wet tropics coast does quite well. This anomaly here shows that rainfall or moisture is going to be moving in from the Indian Ocean moving in through the northern interior through to Western Queensland, northeast South Australia and parts of Western New South Wales. So that's generally what we're looking for and that's what we're looking for in our longrange forecast where we see that cloud band coming right in through the northwest into southern Australia. Following that we should see a progression uh where this actually follows on from into around the 22nd. So the next model shows that this should actually intensify to some extent uh with rainfall anomalies pushing in through the same sort of corridor in through southern South Australia right across Victoria inland New South Wales and southern Queensland. Note, there's not as strong a signal for northeast New South Wales, southeast Queensland, and that's sort of what we're expecting that while we might see rainfall there to be a lot more uh unevenly distributed and and a lot lighter, more fragmented rain compared to what's occurring further west, this this bit of a blob on the southeast coast. This is due to that trough that's likely to form. Uh whether it's an east coast low or just a strong coastal trough, we'll have to wait and see. But this has been trending consistently now for a very long time as well, which is which is positive. Then moving into the end of the month, this this rainfall signal is not likely to form until closer to the 27th and we'll see another northwest cloud band coming in through the Pilra and through the Kimbley. This one can come in a little bit further south. So sort of that Port headland north. So if you're in Karath or Xmouth, we probably won't see any rainfall out of this. This is the next one that can enhance rainfall right through to southern Queensland, northern New South Wales. And because it's coming in on a northern more northern angle, uh this is more favorable for these northern districts. So this is your next opportunity following the week ahead for those regions and then into the first week of June generally average conditions which shows that whatever rainfall event moves across the country won't be significant but it'll bring um you know traditional sort of rainfall totals. We're not seeing anything any major flooding events or anything but we're not seeing dry anomalies which is which is more important than anything. Uh then through June we'll see another few cloud bands if you check long range forecast. Um June's a very active month. This signal through the later part of the month should be pretty much from the Kimbley right across to Queensland and these anomalies through the south will be dependent on a frontal system that moves through about a week later than this. So a lot of this range will be the north.

[00:08:27]This will be the sort of the end of these strong northwest signals. There might be one in July around the 17th um that I'm looking for. We got to wait for the models update on that. But uh generally this will be the peak of of those wetter signals through June. Then if we go to the monthlies, we can sort of see how the months are going to pan out. They've been this has been very consistent as well for for a good 6 months that June will see strong anomalies right through the northwest through South Australia into the southeast. A bit of a a rainfall anomaly on the east coast which would be some sort of a east coast low usually this time of year. So we might see another one through through the first week of June. July we're looking at generally average. So, this is when I'm expecting the wetter signals of June to start tapering off and we go into that more of a cooler, dry pattern from July into August where rainfall will be more so concentrated through the southwest, Western Australia, uh, Victoria and along that southeastern quadrant of New South Wales. Very traditional pattern.

[00:09:24]Um, and it should be a lot of a much cooler and drier month overall with a lot of high pressure ridging um, for July. again, August, I expect these areas in southwest and West Australia, right across pretty much where these orange images are, we should see white at least or moving towards the the lower thresholds of positive outcomes. Then September, I still believe that we'll see more positive outcomes than negative. And being the start of the storm season, how September starts will be a good indicator to how spring ends.

[00:09:56]And we're still looking at a very strong end to spring through November. I'm doing the November forecast at the moment. There is some very positive signals um that we should see some quite widespread thunderstorm activity throughout the month. Definitely much more active than we saw last year uh definitely through the south and that's going to extend right up through eastern Queensland, the Northern Territory, even parts of Western Australia. So, we should see some really favorable conditions in November. um which will offset you know those really dry uh high-risisk wording we're seeing such as El Nino um moving into the coming summer by then the wet season takes over in December anyway and a lot of this this will um be overtaken by the northern wet season dominance and a lot of the moisture comes from the north anyway not from the Pacific or the Indian Ocean so the whole dynamics change once you move into the wet season that's what we'll see in January is usually really wet in Queensland and the northwest and then yeah we're going a bit far with these but to see that we're we're seeing consistent positive anomalies moving into the end of the year uh once we move in through September October uh is is really really good confirmation that we'll see a good end to the year and typically around those harvest times we'll see all those thunderstorms so what you're used to is probably what you're going to get this year as well so it should be quite good overall a quick look at some of these ensembles these are just to look at some of the moisture that we can see over the next um next 14 days. So, if we go to just the accumulations, again, don't look at your location for a specific rainfall forecast. We're just looking at trends here to see what the moisture profiles are like uh from now into the 25th. So, what we're looking for is this this rainfall normally moving in through the Pilgra through the central interior, through South Australia, New South Wales, southern Queensland, Victoria, and Tasmania. And this is this is what we've been looking for in our long-range forecast. The longrange forecast has a lot of these anomalies building up through the Northern Territory more, but coming right down through that central interior. So, that's quite good to see.

[00:11:58]We got some good confirmation there. Uh this is the ECMWF ensemble. If we go to the GFS, it's got a few different versions. It's still showing those anomalies through the um interior. I'll duplicate this so we can we do side by side.

[00:12:17]You'll see that the focus anomalies are through South Australia and through the southeast. So that's the same with this through South Australia and the southeast. So I wouldn't be overly focused on this stuff through northeast New South Wales, Southeast Queensland at this stage. And you'll see that there's moisture coming in from the Pilra and the Kimbley, which also is important. And there's another ensemble here. We can look at GFS.

[00:12:42]You'll see the same sort of pattern where it's coming in through the northwest through South Australia into the southeast. Uh so that's again really positive. What we want to see is um similar outcomes across different data sets not so much the amount of rainfall.

[00:12:57]So this is really good really good confirmation here that this next two weeks this is where the focus of rainfall be. There should be some rain in the southwest but you know this is showing 5 to 10 ms through here. Uh if that happens it's probably going to be more coastal. Anything through the western Australian interior be probably 5 ms or less. And the major systems will be in this this area through the interior and through the southeast.