Complex surf from an ECL; good surf for the longer term too
Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 24th August)
Best Days: Tues/Wed/Thurs: tricky forecast but most locations should see solid E/SE swell, but with the best conditions north from about southern Sydney on Tuesday, possibly extending further south into Wednesday then all remaining areas by Thursday. Thurs/Fri: S'ly groundswell in the mix. Later Sun/Mon: new S/SE thru' SE groundswell.
Recap: Saturday saw an easing southerly swell in addition to a small NE swell, and early light NW winds which created clean conditions at most regions. Both swells eased during the day and further into Sunday, with today seeing tiny waves across the Southern NSW coast.
This week (Aug 25 - 28)
So, we’ve got an East Coast Low developing on our doorstep, and the next few days are certainly looking very complex in the surf department.
The slow moving nature of this system means that there should be an axis point on the coast where conditions are divided between onshore and terrible, and offshore and really good (with the good surf located north of this axis). However, its precise location is unclear and requires a reasonable margin of error: say, around 30-40km.
The best model guidance suggests that this axis point will be across the southern Sydney region. So, locations south from about the Cronulla Shire or the Coal Coast - give or take - are looking at driving E/SE winds on Tuesday, torrential rain and all of the other hallmarks of an ECL event. But to the north - and again, with some flexibility in the precise location - winds are likely to be out of the western quadrant.
Some model guidance also suggests that this axis may slowly move south into Wednesday, which would mean the region of favourable winds should extend south to Wollongong by this time, or possibly even further south.
However, it needs to be pointed out that even with the short range outlook, there are considerable differences between the models as to the precise location of the ECL, and consequently the local winds. It's quite plausible that these estimates will shift around by tomorrow (in which case I'll update in the notes below). Therefore, keep your expectations low as it's hard to know exactly what will pan out across the region.
As for surf - we’re looking at a wide range in wave heights. Locations in the direct firing line of the easterly gales off the south flank of the ECL will see the most size, but conditions will be terrible (set waves should build all day Tuesday and peak early Wednesday morning in the 6-8ft+ range). This looks to be somewhere around the South Coast up into the Wollongong or maybe even southern Sydney region.
North of here, wave heights will be a little smaller but still very solid, peaking around the same time with 6ft+ sets across the Sydney region, and marginally smaller surf up into the Hunter (Tuesday will start off much smaller in size). However these regions will obviously benefit from the much improved airstream.
From Wednesday afternoon onwards, the ECL will weaken so the surf will slowly ease in size through the rest of the week. Conditions remain clean every day with light to moderate offshore winds, becoming a little breeze into Friday as a new system approaches from the south.
Also in the mix on Thursday will be a small long period southerly groundswell, generated by an intense polar low tracking south of the Tasman Sea today and tomorrow. No great size is expected but south facing beaches should see some inconsistent 3-4ft sets that’ll mix in nicely with the easing E/SE swell from the ECL. This southerly groundswell will also ease in size into Friday.
This weekend (Aug 29 - 30)
We’ve got a complex weekend surf outlook at this stage too. The remnants of this week’s ECL are expected to slowly drift south, merging with a weak upper system associated with a series of Southern Ocean fronts. This is expected to form a new low pressure system in the Southern Tasman Sea around Friday, displaying several centres - however it’s as yet unclear how much surf each of them will generate.
Currently, the models are suggesting we’ll see the best surf from this pattern early next week (with a reasonably strong S/SE thru’ SE groundswell) but prior to this - over the weekend - we are likely to see some short range southerly energy from an associated front pushing along the South Coast.
Due to the complex nature of this system, and the fact that it’s still five days away, we really need a few more days to firm things up. But at this early stage it seems reasonable to suggest that there’ll be some small to moderate southerly swell around for part of the weekend at least.
Next week (Aug 31 onwards)
As suggested above, the complex system developing in the lower Tasman Sea around Friday should produce a good shot of S/SE thru’ SE swell early in the new week. Current estimates are for a couple of days of waves, with a peak around Monday in the 3-5ft range at south facing beaches - but I’ll have a better estimate on this over the coming days.
And we're up.. sorry for the delay.
Thanks Ben, legend.
The local buoy in wollongong is already at 3m and rising rapidly by the looks of it
Pity these winds look like the Devils own. Hopefully some dregs in a couple days
Mibs, look at time stamp, that's Friday's data, no update for 3-4 days, would love a fresh feed about now!
Assume we're talking MHL website?
The "Directional Spectrum" for Port Kembla (and SYD) both show todays date and 1900hrs. Surely a reading of 3.1m HS @ 7.1 sec would be from today. Friday was not quite as sizeable - but the period was double.
I think its just the "Wave Data Height and Direction" graph" that's not correctly updating?
Ah yes you're right, but also wrong.
Graph under the spectra is correct, but the spectra is old data.
Perhaps not explaining myself correctly...
I'd think that PK summary data of -
HS - 3.1m
Tp - 7.7s
Dtp - 150 deg
Dp - 152 deg
Look correct? The rest is misleading old data?
Wish they put Hmax back in to that summary! I can't tell what it is unless I am on a computer as unable to navigate it using touch screen on my phone.
Ah, haha what a mess. I'm looking at old URL which has opposite of what you're saying (wrong spectra but correct graph), but the new URL has what you're saying (right spectra and correct graph).
I much prefer that old view!!! You can really see the new swell start to spike! And it has Hmax summary reading (whereas the new one does not include it)
Bloody buoys, they are awesome when they are working but they seem to be offline more than online! Especially when a decent swell hits and you want it the most!
Yes old URL much clearer, and also see the periods around the spectra have been reversed. Biggest periods outside, which I think makes sense but have to get used to.
Ha ha, hadn't even noticed the periods had been reversed :)
Low axis moved north over the Northern Beaches around 6:30pm and looked to settle just over the Hawkesbury with E'ly winds up to Terry Hills, variable at Gosford.
Severe storms moved over as it started shifting south again and now it's all cleared and winds are back to the W/NW.
Love this shit!
Half planning getting out there for the early tomorrow, but for the life of me I just can't see how any swell can be generated to the north of the axis.
So while thinking of getting to the beach, expecting to find not a lot out there.
But I'm just looking at one forecast chart swell, and I recognise that this is highly dependent on where it locates, but am wondering how there can be anything north of the axis, there doesn't seem to have been anything to generate swell there.
BF, it's because the fetch extends out east and even just north of the axis point. See here..
Thanks Craig, hadn't been checking the synoptics prior to yesterday arvo, and the charts I was looking at had no north and east wind (for Sydney) at the time that I was looking, just very strong east, south of Sydney.
Should have got out this morning, went for some exercise etc, and yes Ben, one of the shots below was said to be very nice indeed. From first light there were lines to the horizon, clearly short period and offshore and peaky, which is really just what you need for a beach with shitty banks.
Is that graphic from swellnet site?
Yeah, check them here. Three zoom levels: https://www.swellnet.com/reports/australia/new-south-wales/northern-beaches/wams
Thanks Craig. In retrospect, it wasn't just an issue of not having seen the synoptics from the previous days, but also a resolution issue, where the synoptics aren't showing the winds in between the isobars, or areas where the isobars are seemingly benign, but swirling around a low such as what we had. Will have to remember to check the higher resolution as shown in that graphic.
Wind is starting to swing direction down here,should be nice this arvo.
MHL Directional Spectra has the period reversed and I'm confused. Ben Modra, explain yourself!
BTW the new graphs look great.
Evacuation order issued for Jerrara dam area, 170mm Kiama
All the Sydney cams are cranking!!
yeah the new MHL site is a dogs breakfast
Nice inside bowl at Bondi, with an obligatory closeout behind.
Oh man, this looks fun.
Tama was firing this morning! Best I have seen it in sooooo long. Snapped a bloody new board though...but got some nice shacks first.
Ben, think there is any chance we will get any North in the wind in the morning - say from Cronulla up? (Ideally NW but I'd settle for WNW too)
A little surprised wave heights leveled out for much of the day in the 3-4ft range across Sydney beaches: this morning's ASCAT pass had a secondary trough (or a low pressure centre) immediately east of Sydney - well offshore though - with a focused E'ly fetch aimed perfectly into the Sydney coast. This should provide a small boost in size at some stage - although it hadn't appeared last time I scanned the surfcams. Maybe overnight?
How is the primary swell direction at the Sydney buoy S/SE?
In fact according to the trace (below), primary direction went S/SW around the middle of the day, then S'ly and now S/SE.
Seems odd from a predominantly E'ly fetch (although there is a short range SE component closer to the coast, feeding into the ECL).
It seemed pretty much a due east swell from where I was looking this morning, and still pretty much that way when I checked the cams this afternoon late.
East fetch, east swell.
A HA! There's the expected E'ly pulse I mentioned last night (although the buoy recorded the direction as being SE, and it's apparently now back to the S/SE again).
The surfs looking strong at Manly this morning, shame winds have gone light to moderate S'ly though.
Newcastle on the other hand... fresh NW winds and it's pumping!
Not sure how the new spectral charts are calculating a S/SE swell from this system when the fetch was easterly, and as per the lines on the Manly cam (see screenshot in the post above), the swell direction is obviously E'ly or E/SE.
The surfcam image was from 6:18am, here's the 6am spectral chart:
same with the kembla chart -.. the chart below it reads 135, while the spectra is around 160 .. nearly 45 degrees out?
Check the dates - some of the spectral charts are a few days old.
Winds slowly swinging too.. now S/SW at Bellambi and Kurnell.