Cyclone Alfred remains a Category 2 tropical cyclone and is still expected move into Brisbane and surrounding regions tonight and through Friday. The cyclone has a bit of a messy path as it’s basically in an area that allows it to stall off and on - meaning it may move westwards, then stop, even move in a circle for a time.
We break down wind, rain and waves - plus how Alfred’s remnants may affect Sydney and other large parts of NSW going into the start of next week.
This is a messy cyclone to be precise about - we do our best to break it all down.
We have another Cyclone Alfred special update on Friday morning Queensland time
We break down wind, rain and waves - plus how Alfred’s remnants may affect Sydney and other large parts of NSW going into the start of next week.
This is a messy cyclone to be precise about - we do our best to break it all down.
We have another Cyclone Alfred special update on Friday morning Queensland time
Category
😹
FunTranscript
00:00Hello, kia ora, g'day, I'm Philip Duncan from Weatherwatch TV on YouTube, with your Cyclone
00:09Alfred update for Thursday.
00:10Let's get into the tracking at the moment.
00:12So Category 2, as it's been for the last couple of days, curving around, and then in the last
00:1724 hours or so it started that westwind movement towards land, but you might have noticed it
00:21hasn't moved very much.
00:23The lines here indicate basically the cyclone's been stalled for about a day.
00:28It is going to start moving back up again as it moves inland.
00:31There's some computer modelling that suggests what you see out here at sea might again happen
00:36around the Brisbane area as the cyclone starts to break apart, but lingers over the top of
00:41the Brisbane area.
00:42So we're going to break this down for you to try and make some sense of it, but basically
00:45here is the Bureau of Meteorology tracking and the warnings that go from Tin Can Bay
00:50all the way down to about Grafton.
00:52Let's have a look at the current wind speeds.
00:54The gusts that you see in red, those are gale force.
00:57You can see them popping up all along the eastern coastline from New South Wales all
01:01the way to well north of Brisbane.
01:03The windiest weather though is out at sea in the southwestern quadrant of the cyclone,
01:08that is right here, the centre of it very calm.
01:10You can also see some rain coming through, heavy falls starting to develop now, but the
01:15worst of that rain is yet to actually arrive.
01:18Let's make more sense of it.
01:19Why is the cyclone stalled?
01:21Well it's all due to the big picture.
01:22You've got to have a look at, zoom right out and see where the high pressure zone is, south
01:26of Australia, south of South Australia.
01:29This anti-cyclone is stretching all the way down to Antarctica, all the way up into Australia,
01:35but it balloons out into the Tasman and all the way up towards the tropics, and it's this
01:40sort of ballooning out action over the Tasman that has got this cyclone trapped like a wheel
01:46stuck in mud.
01:47It's just spinning around, wants to pull towards New Zealand, it can't because the high pressure
01:51zone is coming in and blocking it, and eventually as the anti-cyclone increases, the high pressure
01:56increases in the Tasman, that's what will guide Alfred in towards the coastlines of
02:01Australia.
02:02So let's start off with the wave heights, they are the biggest, most widespread part
02:06of this system to start with.
02:08You're looking at some really big wave heights coming in, I mean as you already know for
02:11the last couple of days, Brisbane is right here.
02:14So you're talking about wave heights of six, seven metres along the coastline.
02:18We already have seen waves recorded over 15 metres, and these waves are going to intensify.
02:23Let me animate this for you, you'll see this area here pushing in to the coastline, going
02:29all the way down to about Byron Bay, even further south than that, and you're talking
02:32about wave heights of eight, nine metres or more as we go in towards the next couple of
02:37days.
02:38So that is significant, and on top of that, you've got all the wind blowing with it.
02:41So as those swells come in, as those big waves come in, you've got this enormous strong wind,
02:46just south-easterly pushing in with it.
02:49That all builds up the tides along the waterfronts, blocks up the rivers trying to exit and going
02:54out to sea, and that's one of the reasons why coastal flooding, or coastal inundation
02:59as it's sometimes called, is a concern.
03:02That's where the estuaries just start to keep filling up, they don't go down at low tide,
03:06and so that could be an issue in some of these very low-lying areas along the coastline.
03:11But let's jump forwards, because this is a slow system, and even by tonight, the worst
03:14of those winds, they have intensified, but they're offshore.
03:18So you'll notice them from places like Mullumbimby, further northwards to about Jacob's Well,
03:24in that area on the Gold Coast, that is the strongest winds.
03:27And also here, along the Macpherson Ranges, you're likely to see some big gusts coming
03:31over the hills there, especially on the Queensland side as that southerly comes up, races down
03:37on the northern side of those ranges.
03:39Also around the Tweed Range, and also Mount Warning, you're likely to be seeing some gusty
03:44winds moving through there, especially as we go overnight tonight.
03:48Now the computer modelling, based on which one you use, they're all pretty similar, but
03:52they're all just a little bit different enough to change how it looks a wee bit over land
03:57as far as the biggest gusts are concerned.
03:59But this looks like the peak of it overnight tonight, all the way from Yamba up to about
04:03Brisbane.
04:04Those are the most at-risk areas, and you can see again here along the ranges, as those
04:09winds howl through, they pick up even further on that northern side going into Queensland.
04:14That's where you can see a higher risk of damaging gusts.
04:17Even going in as far land as Toowoomba, you might be getting some of those damaging gusts
04:22that far inland.
04:23But let's go through into Friday morning further.
04:26This is when the cyclone is likely to be really coming in close to land.
04:30Like I say, the models are changing, we've seen this just in the last 24 hours, it is
04:34frustrating that we can't just give you the answer as to where, exactly what time it's
04:38going to happen.
04:39What you notice is as we go through Friday morning, the area of severe gales and this
04:45pink purple shading, this is where it goes off the key, that area there is reducing.
04:50And so that's quite normal, probably getting down to a Category 1 cyclone by this point.
04:55And by tomorrow night, looks messy doesn't it?
04:59It's not 100% locked in, what you've seen there is perhaps the low spinning around and
05:03moving back out to sea for a while, and that could allow the winds here to ramp back up
05:08again.
05:09It's frustrating because we can't give you a nice clean answer to tell you where this
05:13is all going to go.
05:15But we can tell you by the weekend we expect the low to be well inland, starting to fall
05:19apart, windy gale force weather pushing well through the interior, and now you're seeing
05:24the winds change along the coastline, north easterlies, which means it's still going to
05:29be blowing back into the rivers that are trying to drain out.
05:32And of course by the time we get into the weekend, that's when the heavy rain is especially
05:37setting in and trying to drain back out.
05:39So this is a slow moving wind event, it moves inland by Saturday night, Stanthorpe down
05:45to about Armidale, getting those gusty winds, could be damaging as they move through.
05:50And we're still seeing very strong winds all the way from Maroochydore, all the way down
05:54the coastline, but especially down to about Lismore area, those gusts are still potentially
06:00in that damaging zone where you could still get power cuts.
06:03And look, let's jump through here to 1 o'clock Monday morning, it's Sydney's turn, and southwards
06:09to get that gust of north easterly winds, low pressure is inland, and it's all tracking
06:14southwards as you go across the day.
06:17Let's get into rainfall now, here is the 24 hours of rainfall taking you through to 10am
06:21on Friday, and it's what I've been saying for the last couple of days, basically Brisbane
06:25down to about Evans Head, that's the area, especially around the northern rivers, getting
06:30that very heavy rain.
06:31We talked about the McPherson Range, the heaviest rain is likely to be on the southern and eastern
06:37sides of that, which drains southwards and then out to sea.
06:42On the other side, drains northwards and then out to sea.
06:44So this very heavy rain coming in from the east, perhaps the southeast, heaviest falls
06:49south of Surfers Paradise and north of Lismore.
06:53Going through to Saturday, heaviest rain from the Gold Coast down to about Yamba, those
06:58are the areas seeing the heaviest rain, but the bulk of that rain does once again look
07:02to be on the New South Wales-Queensland border as it comes on in.
07:06And further southwards, heavy rain from Coffs Harbour down to about Port Macquarie along
07:11the Great Dividing Range, you'll be seeing those heavier falls.
07:16Sunday, notice the pattern here, the heaviest rain still in this zone, spreading down further
07:22through the divide, heavier falls easing off a wee bit perhaps further southwards, but
07:27this is a long-lasting rain event that basically is around for about three or four days.
07:32It breaks up on Monday, that's the first time you get those showers kind of coming through,
07:36dry spells, might even get the sun out if you're lucky on Monday, but the rain moves
07:41down now towards Sydney, so Sydney's got wind and rain coming through on Monday, and obviously
07:46everybody around you as well, all the main centres in this area, likely to get a burst
07:50of wind and rain, there is the low coming back out to sea again.
07:54So let's have a look at that rainfall, here is the animation through to Sunday, and you
07:57can really clearly see which areas are most exposed to the heaviest rain, and of course
08:01the black line here, that is the top of the Great Dividing Range, so the rainwater that
08:06falls along that line eastwards drains out to sea.
08:10So this whole area, basically Brisbane to Port Macquarie, that is the highest risk for
08:16flooding that we can see at this stage.
08:18It may occur in other places, so please keep up to date with the Bureau of Meteorology,
08:22they are tasked with giving you the official warnings.
08:25But this is a messy system, dry mostly on the top half of it, big rain clouds exploding
08:30to life in the southern edge of it, and that is all tracking slowly in, and it's this area
08:35here with these explosive clouds with the very heavy rain, that is the area moving right
08:40in to that border.
08:41So this is the best we can do today with this very conflicting data that we've got.
08:46But we'll be back again tomorrow Friday, and we'll give you another update then, and hopefully
08:50finally by then, we can give you a bit more clarity as to when this is all going to be
08:54over and done with.
08:55Thank you for joining us, we'll see you again tomorrow.