Australia: This Severe Storm Will Bring Downpours... – Transcript

00:03Good day, guys. It's Josh here from Cyclones Oz for your detailed Australiawide weather forecast update on Monday the 12th of October, 2026. And we've got a lot to talk about today, including a thunderstorm, a potentially severe thunderstorm risk across northeastern New South Wales and southeastern Queensland. The first day of the year that I would actually describe as a proper severe thunderstorm chance. Then we're going to see a big increase in rainfall across Queensland over the next couple of days. And that's going to translate to some of the most significant falls we've seen in the past 6 months. and all the details, plus a whole lot more coming up in today's

00:31weather with weather forecast update. So, if you are brand new to the channel, please do consider subscribing. But let's get stuck straight into the forecast across northeast New South Wales and southeastern Queensland. I'm just going to skip over today. There is a chance of thunder across the coast, uh particularly just towards the north of Brisbane into the Sunshine Coast and maybe into far northeastern New South Wales. The severe risk is pretty much right down at zero. Maybe some afternoon rumbles or two in your neck of the woods, but at this point in time, doesn't warrant mass concern. Tuesday is the day to be watching quite closely.

00:57We've got a big surge of moisture coming in off northwestern Australia and this is the precursor precipitable water for that thunderstorm activity. However, there's probably a little bit too much of it. You can see here on the forecast models an extremely saturated profile being pushed into the region being drawn out of northwestern Australia here by a strong cold front that's invecting over southern Australia this morning. And that's going to translate to a very moist and unstable air mass priming itself over southeastern Queensland and

01:23northeastern New South Wales by Tuesday morning. Now, a lot of moisture like this is going to create a few problems. One of which is going to be AM convection or shower activity through the morning hours out here through southern Queensland and Northern New South Wales. As I've discussed in previous forecast updates, this is going to continue to translate to widespread shower and thunderstorm activity through the region, but it's sort of going to put a roof onto how strong these thunderstorms can probably become because the instability out here is going to be a little bit weaker as a

01:50result of a lot of that cloud cover. As a result, you'd generally be expecting non- severe thunderstorms out here through Tuesday morning and afternoon. The thunderstorm activity is actually expected to get going pretty early. So, places such as Roma or Mori could have thunderstorms rolling through their areas by 8 or 9:00 in the morning.

02:06Closer to the coastline, it is expected to start off clearer here through the southeast coast and into northeastern New South Wales, which will mean a hot and humid day will build. And that will allow for those instability values to really flourish and blossom throughout the course of the day. And as a result, you can see a very unstable atmosphere establishes itself through southeastern Queensside and northeastern New South Wales by Tuesday afternoon. An atmosphere that I'd consider a lot better primed for thunderstorm activity with most unstable cape values exceeding

02:322,500 jewels per kilogram. Bulk sheer values are a very interesting topic of discussion because we do have an upper disturbance nosing through the region here, particularly through northern New South Wales sometime on Tuesday afternoon. But you can see that arbiter disturbance sort of lacks behind where that greatest instability and surface heating is expected to be. So as a southerntherly change develops here and arrives up the New South Wales coastline through the afternoon hours sort of associated with that surface cold front.

02:56You can see that wind shear is still lacking. It's still well out in towards western New South Wales and Queensland, which means our bulk shear values across the southeastern coast and into northeastern New South Wales. Might actually be a little bit on the lackluster side through Tuesday, which would be less favorable for widespread thunderstorm activity and certainly less favorable for widespread severe thunderstorm activity. This is mitigated somewhat by the passage of that surface suddenly that's going to ride up the New South Wales coastline. You can see that here expected to be quite strong through

03:24Tuesday night into early Wednesday morning. And as a result, some late evening uh supercell thunderstorm activity here through the northern corridors of New South Wales cannot be written off at this point in time. And that's sort of where my severe corridor is expected to be through this sort of area here along the northeastern New South Wales coastline. Another reason for these risks being held back is this saturated environment is creating another thing. It's really shallowing those lapse rates, which is how fast the atmosphere cools as you ascend with height. The faster it cools with height,

03:52the greater the chance of large to giant hailstones and the more powerful an updraft can be to support those large to giant hailstones. But with a very rain entrained and messy environment like this with a lot of moisture moving through, those lapse rates become a lot shallower and as a result that risk of large to giant hailstones really does begin to curb off. So a very moist environment here right through the profile which you can see here at 700 HPA at 500 HPA and then up at 300 HPA and right up to the top of the

04:19atmosphere up at about 200 HPA we have got saturated profiles right up to that altitude here and as a result lapse rates or that cooling with height is pretty weak and the chance of very severe thunderstorm activity as a result of those lapse rates is also pretty weak as well. In fact, the number for northeastern New South Wales, those laps rates are about 5 to 5 1/2 degrees. You typically want to be seeing about 7 to 7 1/2 degrees for severe thunderstorm activity to be quite dangerous uh in on the hail front here. It could still

04:46create damaging wind gusts and heavy rainfall and certainly this looks to be a heavy rainfall environment with how much moisture there is. But in terms of giant hailstones, this is not ringing alarm bells by any stretch of the imagination whatsoever. When you're talking about severe uh severe meteorology or severe thunderstorm meteorology, it's like baking a cake.

05:03It's uh just a matter of how those ingredients interact with each other. And to bake a delicious cake or in this case here, a perfect severe thunderstorm environment. You need the perfect amount of these ingredients and you need them to mix just right. You need them to interact with each other just right. You can't cook them on too high of a heat or you can't cook them on too low of a heat, otherwise it just wrecks everything. And in this case here, we've got all the ingredients beginning to nose into the right locations. But it's sort of like putting the cake in the oven and then cooking it and then adding the egg afterwards. The ingredients are

05:30there, but it's still going to taste pretty terrible. And that's the best way that I can describe this severe thunderstorm environment is the ingredients are there, but they're not mixing and they're not interacting with each other in a necessary way to get a wild severe thunderstorm outbreak off the cards. Actually, the best way that I can show you where that severe thunderstorm activity is expected to be is over on our frontline maps, handone every single day. And for just $40 a year by clicking the subscribe button down in the pinned comments, you get access to all of these information maps here, plus a whole lot more of severe

05:58weather intelligence. Now, if we're talking about the risk for tomorrow, Tuesday, you can see that corridor here through northeastern New South Wales, correctly identified by this convective outlook here. So, places such as Port Mcquaryy up through Coughs Harour, Grafton, and Lisbour, sort of where that severe thunderstorm chances are or at their greatest. But you can see there is an environment that is loosely supportive of severe thunderstorm activity extending right in towards southern and western Queensland as well as over the Brisbane metro area, but it's a lot more fringe and it's certainly a lot lower end than what

06:26we're talking about across northeastern New South Wales. Not that I'd call this high-end by any stretch of the imagination, but it's definitely a lot more tapered in comparison to that risk over the border into New South Wales. So that puts places like Brisbane, the Gold Coast, and certainly the Sunshine Coast in a marginal risk or an environment that is marginally supportive of thunderstorm activity, but more supportive of that general storm activity. And as a result, whilst a storm is very much possible, in fact, it's probably getting close to likely for the Brisbane metro area through

06:53Tuesday, what it's going to be is a few bolts of lightning here and there coming through. Maybe some small hailstones, maybe some heavy to locally intense rainfall, some strong to locally damaging wind gusts. But as opposed to the risks that we're used to seeing at this time of the year, like giant hailstones, or even a tornado threat, I know I've seen that word thrown around a few times in the last couple of weeks.

07:12Uh it really doesn't look like that's the environment that's manifesting itself for Brisbane or the Gold Coast. So, should you be concerned? I would certainly not be concerned about this environment whatsoever. It definitely looks like quite a messy and uh very marginal environment at the best of things. So, whilst the severe thunderstorm risk is certainly there across southeastern Queensland as well as through wide swaths of northeastern New South Wales, it's by no stretch of the imagination a high-end day. And whilst I'm not ruling out very dangerous thunderstorms from developing, if one

07:39does develop, it's expected to be quite isolated. But remember, it only takes one severe thunderstorm to move through a major population center such as Brisbane and the Gold Coast. And as I've discussed, even though the environment is not overly supportive of that, it's not completely unfavorable for a severe thunderstorm to move through the Brisbane or the Gold Coast metro area.

07:56And tomorrow is the first day, properly the first day, where you've got to be watching the radar and keeping up to date with severe thunderstorm warnings and information as the day draws on because it only takes that one storm to go through and really mess up a whole bunch of things for it to be classed as a significant thunderstorm outbreak.

08:13Now, as we move things out towards Wednesday, still thunderstorm activity expected to be quite widespread across Queensland. Bulk sheer values are going to be increased out here across the Capricornia coast. So places such as Rockampton, Gladston, and Bundberg. And as that southerntherly change noses into the region, again, a very cold and stable, dense air mass moving into an environment of warm and uh unstable air mass. And that's going to result in thunderstorm activity being quite widespread through Wednesday afternoon here through these regions of central Queensland. Some of which could

08:41potentially be severe. Still a bit too long range for me to properly understand the proper severe elements of this environment here. It does look like the upper pattern is a little bit nebulous right now and maybe a little bit on the unfavorable side for severe thunderstorm activity at least in a widespread sense.

08:55But certainly around the Rockampton and Gladston area, I wouldn't be ruling out one or two severe thunderstorms through the afternoon of Wednesday. And again, these thunderstorms here being quite slow moving along that southerntherly change could have some very heavy rainfall within them as well. Similar to the thunderstorms we are likely to see tomorrow, Tuesday through southeastern Queensland. So, this can be quite an interesting outbreak to uh to monitor quite closely here through central Queensland as we move out towards Wednesday. Thursday is when the rain starts and this leads me very nicely on into the big part of the forecast

09:23update. This dramatic increase in rainfall across central interior portions of Queensland. Essentially, it's been driven by a big surge of mid-level moisture. You can see that quite clearly here at 700 HPA. We've got that big band of moisture developing here across central Australia that's beginning to be pulled over in towards New South Wales and Queensland ahead of thunderstorm activity that we've just discussed for tomorrow. And then as we move in towards the later portions of the week, this big plume of moisture is going to establish itself properly over central Queensland from Thursday

09:51onwards. And as you can see here, that will be an environment very favorable for widespread rainfall, recurring thunderstorms and shower events. And this will quickly add up in as significant rainfall over the region. We need to keep in mind we're still in October here. So we don't have that warmth advecting off the Coral Sea at this point in time. So that's going to be a little bit of a lid on the rainfall potential that we're going to see here through Queensland. It's not going to be a monster dramatic major flooding event

10:16that we might be seeing in summer. You know, 250, 350, 450 mm. It doesn't look like we're going to be seeing widespread accumulations anywhere close to that caliber. But at this point in time, forecast models are painting a very wet picture from Thursday onwards. And you can see here 7-day rainfall accumulation from Thursday. The bulk of which will actually fall into the first 3 days of this forecast range here. Widespread now increasing from that 30 to 60 mm mark.

10:39Probably closer to that 50 to 100 mm mark that I highlighted as being a bit more of a looser probability. So widespread very healthy rainfall accumulations are expected out here again from recurring thundery downpours. There will be winners and there will be losers. As you can see here, this forecast still calls for patchy accumulations. There are spots that are heavier, like in these purple shadings, and there are spots that are lighter, such as in those orange shadings. And you can see the difference between that purple there, just south of Emerald, 148 versus 36. There are going to be winners

11:08and losers here in this rainfall forecast, but there looks to be a lot more winners than there will be losers in this rainfall event here. Rainfall and thunderstorm coverage is at its most widespread and heaviest with the potential for severe thunderstorm activity through central western Queensland around the Long Reach area from Thursday and then out towards Friday. In the similar areas, Saturday and Sunday, thunderstorm and shower activity is expected to be very widespread still. However, from Sunday onwards, that shower and thunderstorm activity eases back quite considerably.

11:34And with still a few patchy showers and a lot of cloud cover expected through Monday and Tuesday, rain chances will continue. But the rainfall is expected to be a lot lighter and probably more contracting to the coastline as we move in towards the middle portions of next week. but still a very widespread and prolonged rainfall event and definitely the best rainfall potential that these areas have seen in many many months which is fantastic to see. Forecast models are increasingly congruent that this is a central Queensland rain event.

11:59So the northern Capricornia coast through the central cofields and highlands the um wargo marinara the southern portions of Queensland excluding the southern downs and then out in towards central northern Queensland here through the central coast and wit Sundays and then out to about the long reach area here which I believe is nosing into the channel country. I'm a little bit shaky on my Queensland geography right now. As we discussed and accurately identified a few days ago, but also broke down in great detail in yesterday's two forecast