Incoming south swell for the North Coast

Ben Matson picture
Ben Matson (thermalben)

Southeast Queensland and Northern New South Wales Surf Forecast by Ben Matson (issued Wednesday 7th May)

Best DaysThurs/Fri: several stages of building S'ly tending S/SE swell, strongest later Thurs, mainly Fri. Won't benefit SE Qld until Fri due to the predominant S'ly direction prior to then. Sat: good S/SE tending SE swell easing, with light winds. Sun: small fun waves with light winds. Next Wed/Thurs/Fri: building trade swell across SE Qld.

Recap: Continuing small surf across the SE Qld region, but with plenty of strong south swell in Northern NSW early Tuesday ahead of an easing trend during the day and into this morning. A new south swell filled into the lower Mid North Coast this afternoon and will build overnight across the North Coast tonight (note: an apparent increase in new swell at the Byron buoy this afternoon is likely to be local windswell rather than new groundswell, as evident by the concurrent drop in significant swell period, as well as the wind switch from a fresh W/SW thru’ SW to a strong S/SW tending S’ly). 

This week (May 8-9)

There's no shortage of south swell for the rest of the week, but fresh and gusty southerly winds will generally confine the best waves to sheltered locations. 

Right now we’re seeing an increase in mainly short range S’ly swell, but some mid-range energy has already reached the Mid North Coast and will fill in across remaining regions overnight, generated by a strong fetch that entered the southern Tasman Sea yesterday.

In addion to this, later tomorrow afternoon a new long period S/SE swell will make landfall across the lower Mid North Coast and this particular pulse is expected to provide the biggest waves of the forecast period.

BUT.. it’s very important to differentiate between all of these swells, because they will all have a different result at the coast.

The initial short range energy really won’t provide much value in the surf zone, because the short period and low strength won’t allow for much refraction into those locations offering shelter from the accompanying southerly wind. Fortunately, this swell will mainly dominate the overnight time frame so it's relatively inconsequential as a whole.

The mid-period energy due through much of Thursday will do a better job, but I’m skeptical that we’ll see much size translation north of the NSW/Qld, again owing to the short swell period and the southerly swell direction. Exposed south facing beaches in Northern NSW should pick up some 5-6ft sets on Thursday but they’ll be heavily wind affected. Semi-protected points will be a better option but the swell lines probably won’t be overly well-formed so it’ll be smaller and more sectiony. Southern corners will be very small.

Expect generally small average waves throughout much of SE Qld on Thursday with bigger but wind affected waves at exposed south facing beaches.

The new long period S/SE swell expected to hit the Mid North Coast late Thursday afternoon is looking the best of all. This swell was (and is still being) generated by a small secondary low pressure system located near Macquarie Island on Monday, which merged with the tail end of Tuesday’s front that tracked through the lower Tasman Sea. The combined system has then pushed north through our S/SE swell window. 

Storm force southerly winds developed later yesterday well SE of Tasmania, and because they’ve been working on an already active sea state, we’re looking at the arrival of a very large, powerful swell across the entire NSW coast.

However, I have some concerns around the timing of this swell in Northern NSW. The leading edge of this swell is due into the Port Mac region from early-mid afternoon onwards, and should produce some very big waves about exposed south facing beaches in the 6-8ft range by the end of the day (with smaller 4-6ft waves at remaining open beaches, and smaller surf inside southern corners).

Unforunately, we may not see this swell arriving across the remainder of the North Coast - say, north of Coffs or Yamba - until very late in the day. Which means that we’ll be looking at a twelve hour period under the cover of darkness where this swell will be at maximum capacity across the coastal margin.

There is certainly a chance for an earlier-than-expected arrival but I’d be hedging my bets at locations further south, rather than further north. And the Gold/Sunny Coast certainly won’t be getting a look-in on Thursday.

So, this means Friday is probably going to offer the most value from this S/SE groundswell, with the early morning showing the most size. A slow downwards trend is expected during the day but the morning session should still be somewhere around 6-8ft at exposed south facing beaches across Northern NSW. 

In SE Qld, this swell direction should work a little better than the southerly swells we’ve seen in recent days. Again, there’ll still be a wide range in wave heights between the majority of the coast (2ft+) and exposed south facing beaches (4-5ft) but there should be a much more diverse range of options across the region. Expect some inconsistency here too owing to the swell direction and wide range of periods. 

Winds are looking a little mixed across the region on Friday; generally light and variable across the Mid North Coast, tending moderate to fresh SE across the North Coast and up into SE Qld. However periods of early SW winds are possible, which may create some great waves across the various points and reefs during the morning. 

This weekend (May 10-11)

The weekend forecast has improved a little since Monday’s outlook. We’re looking at a slowly easing S/SE swell all weekend but there’s now more confidence for a little more size on Saturday morning, owing to a short stalling of the Tasman low by the computer models in recent runs. 

This ‘stalling’ is expected to occur early Thursday morning in the south-eastern Tasman Sea, whereby the low briefly re-intensifies around a small secondary centre to the south, giving a slight renewal in new swell energy that’ll probably arrive early Saturday morning.

It won’t so much increase the surf as arrest the easing trend - this should maintain 3-5ft waves across exposed south facing beaches on the North Coast for the early session on Saturday ahead of a drop throughout the afternoon. Smaller 2ft+ surf is expected throughout the Gold and Sunny Coasts early morning, reaching 3-4ft at their south facing beaches. Smaller surf is expected into Sunday. Light variable winds should maintain generally clean conditions all weekend.

Next week (May 12 onwards)

There’s a couple of sources of new swell on the cards for next week. First and foremost, we have a mega swell heading to Tahiti next week (expect footage of 15ft Teahupo'o to appear on the interwebs sometime late next week), of which the primary low responsible for this - well to the S/SE of New Zealand on Friday - is expected to stall and form a small but intense band of storm force SE winds off the ice shelf, aimed at the Australian East Coast.

The small fetch length, short duration and large travel distance will probably restrict wave heights to just a couple of feet at exposed beaches, but if you see some long period (~16 second) from the SE arriving sometime later Tuesday or Wednesday, you’ll know where it came from.

A trough is expected to form off the central/southern NSW Coast early in the week but at this stage it’s expected to be aimed towards the southern half of the state (there’s a chance that the Lower Mid North Coast may pick up some energy, but I’ll reevaluate that on Friday). 

Of more interest to the SE Qld region are the trades south of New Caledonia, which are expected to muscle up early next week as high pressure system in the eastern Tasman builds a narrow ridge across the South Western Pacific. Although no major swell is expected from this source, we are looking at a building E’ly swell from about Wednesday onwards that should deliver some fun peaky waves across the Gold and Sunshine Coasts into the second half of the week and possibly next weekend. I’ll take a closer look at this on Friday.

Comments

mitchvg's picture
mitchvg's picture
mitchvg Friday, 9 May 2014 at 1:34am

Aaaand a code brown on seabreeze, at DI, has killed the week long froth in an instant :(

Sheepdog's picture
Sheepdog's picture
Sheepdog Friday, 9 May 2014 at 8:56am

Mitch, all reporting sites have sunny coast at 1 to 2 foot, 3 foot max, from the sse..... In all the 20+ years of watching 2 foot sse swells, noosa 1st point is a mill pond, as is nationals... I mean mill pond.... Lake..... So, for there to be tiny little manicured lines, probably 14 to 15 seconds apart, that would indicate something out of the east as well... Qld wave buoys confirm this....Yeah, very inconsistent.... But don't be surprised if there is a little pulse after low tide this morning.... My favorite "secret spot" will have a few nice little 2 -3 foot sliders.... at around 10 am- midday.... A wait between sets though....Cheers....

mitchvg's picture
mitchvg's picture
mitchvg Friday, 9 May 2014 at 11:10am

Cheers SD, but I'm saving the froth for 6ft reefs or points. Going souuuuuuuth tonight, past the cow paddocks. To a place where Zenny would think, dolphins... Anyway, I don't actually know the track you're talking about. And I don't mind the romance of the mystery that you and dro speak of!

But yes, you could make an argument for that swell coming from the pac, but it's contaminated with multiple south swells (seen on Byron bouy). I'm surprised actually, the southport buoy seems to be hinting at 1.5m E groundswell, which could easily be 3,4,5 ft. But looking at the Mbah buoy...


Size: increasing
Period: windswell (S) contamination increasing also. But spikes of groundswell seem to match up with spikes in E direction.
Direction: SSE to E (I know not 100% reliable due to bathymetry). Normally I'd say that the direction and period change go hand in hand, but the winds don't agree.

donweather's picture
donweather's picture
donweather Friday, 9 May 2014 at 4:30pm

Again, you have to take the wave direction of the SE Qld buoys with a wee little grain of salt. Brisbane Buoy is the most accurate with respect to swell direction due to it's additional depth of water. SE Qld buoys will generally only show generic trends, rather than exact specific swell direction. ie its from the south, east or north, but trending more S/SE, E/SE or E/NE as it moves/changes direction.....if that makes sense?

mitchvg's picture
mitchvg's picture
mitchvg Friday, 9 May 2014 at 10:27pm

Haha that last bit didn't really make sense. Sometimes though, the moreton bay buoy can pick up changes in secondary, e'ly swells, when the pt lookout buoy is overpowered by S

donweather's picture
donweather's picture
donweather Friday, 9 May 2014 at 9:10am

Yep, forecast was also forecasting a small 2ft E/SE swell at around the 12-13 sec mark, more so this afternoon, but if it's already at 2ft in the water now, then yep, it might be slightly bigger after lunch. But shhhhhhhhhhhh, don't tell anyone!!!

yocal's picture
yocal's picture
yocal Friday, 9 May 2014 at 9:13am

I notice that the Model has run between 4 and 6ft SF beaches on the Gold Coast forecast since thursday and through to saturday, but reports are showing 2-3ft today and yesterday. What is the likely reason that we aren't seeing the size anticipated by the models?

thermalben's picture
thermalben's picture
thermalben Friday, 9 May 2014 at 9:20am

Yocal, this is one of the flaws of our wave model - it overcalls south swells of this nature. We're not sure how to peg it back but have a couple of ideas that we'll implement over the next month or two.

Sheepdog's picture
Sheepdog's picture
Sheepdog Friday, 9 May 2014 at 9:32am

Don, well.... This is forecaster notes... ;)

donweather's picture
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donweather Friday, 9 May 2014 at 12:37pm

I meant don't tell everyone where to go and when!!!

EWOK's picture
EWOK's picture
EWOK Friday, 9 May 2014 at 2:14pm

G'day Ben / boyz - doin a roadie from sydney to Byron from the 15th for a few days and long range model forecasts aren't looking that good, can you see anything coming? Cheers!

thermalben's picture
thermalben's picture
thermalben Friday, 9 May 2014 at 2:33pm

Will have an updated forecast up in a few hours.

yocal's picture
yocal's picture
yocal Friday, 9 May 2014 at 2:54pm

Cheers Ben,
south swells are always hard to predict locally too (ie where will pull the most size). What factors lowered your confidence in the swell delivering as the models predicted in this case? Ie; distance from source/ period/ direction (ie variance by units of degrees)?

thermalben's picture
thermalben's picture
thermalben Friday, 9 May 2014 at 3:03pm

Just a trend I've seen since we've had this model running.

Actually, I still use some manual forecast methods to estimate surf size (I'll usually eyeball surf heights from a 10m wind chart), but then I'll cross reference it to our model's predicted surf height to hone in on the timing. 90% of the time they'll match pretty closely but almost every single time with these ridgey south swells (ie containing a high percentage of short/mid range energy) it'll overcall size at south facing beaches in SE Qld (and the Sunny Coast more so than the Gold Coast). 

In fairness, I don't think it overcalled this one too much - I've been watching the Burleigh surfcam and saw plenty of 2ft+ waves this morning (model forecast was 2-3ft for the GC and 3ft for the SC) - the main error was at south facing beaches.

thermalben's picture
thermalben's picture
thermalben Friday, 9 May 2014 at 3:07pm

Actually one tool I think would be handy (mainly for SE Qld forecasts) would be to default 'off' the south-facing beaches size call. It's much more important in NSW (and much more obvious), however in SE Qld there are only a handful of south facing beaches - the greater GC and SC surfing regions are sheltered from the south.

And under sustained periods of southerly swells, the yellow bars are somewhat distracting. So perhaps we should offer an option whereby you can turn "on" the yellow bars if you want to see how big south facing beaches are likely to be.

Just a thought anyway. 

mitchvg's picture
mitchvg's picture
mitchvg Friday, 9 May 2014 at 3:37pm

That could go either way I reckon. Some people use the site (app too) for 2secs and don't flick it off and complain about overcalling (not you yocs). Some people find it and flick it off once, then forget and complain about missing swells. If someone's onto it, they're onto it I reckon.

thermalben's picture
thermalben's picture
thermalben Friday, 9 May 2014 at 3:40pm

Great points (and the reason we didn't offer this option in the first place).

I'll have a think about how we can make it more user friendly.

Sheepdog's picture
Sheepdog's picture
Sheepdog Friday, 9 May 2014 at 3:36pm

Donny, Mark Pridmore covered "where" and "when" this morning.... I was covering "why"... Not a south swell.... As for the "secret spot", well..... Only the most rusted on viewer of forecast notes would know that.... Even Mitch (above) can't figure it out.... ;)

mitchvg's picture
mitchvg's picture
mitchvg Friday, 9 May 2014 at 3:39pm

Mate, I think you were dropping hints about it when I was up north, so just skim read it for later reference. I know a couple sponger spots you haven't mentioned anyway SD ;)

donweather's picture
donweather's picture
donweather Friday, 9 May 2014 at 4:27pm

SD, Mark's report from this morning is copied directly below:

"the SSE swell has increased a bit overnight but still not alot of it gettin in due to swell direction...1- 3 ft and wth the southerly winds already blowin a bit , the quality isnt that good, so best bet is to find a beachy that handles the southerly winds but also is gettin a bit of the southerly swell, or try the points that are cleaner but smaller but there's a few little mal sliders if ya keen.....Winds were predicted to be SSW early but they definitely are Southerly atm....at least its getting bigger..."

I don't see any mention of the word "Noosa" or "But don't be surprised if there is a little pulse after low tide this morning" both of which you mentioned specifically where to go and when!!!

Sheepdog's picture
Sheepdog's picture
Sheepdog Friday, 9 May 2014 at 5:04pm

Well, being the "sunshine coast report", and considering mark said "the points"..... and considering swellnet has a noosa cam at the bottom of Pridmore's report, and considering the "secret spot" isn't even named, or within viewing of the camera....... A bit pedantic? Come on Don... Please... I'm still getting over that nut job the other day.... Let me off the hook mate :)

boogiefever's picture
boogiefever's picture
boogiefever Friday, 9 May 2014 at 9:40pm

A ha ha ha ha ha ha ha ha...........tool.

Sheepdog's picture
Sheepdog's picture
Sheepdog Friday, 9 May 2014 at 10:44pm

Speaking of sponger spots... The crustation has crawled out of its hole.

BTW, Mitch, Don... The Caloundra buoy aint bad.
http://www.ehp.qld.gov.au/coastal/monitoring/waves/site_param.php?siteid...

mitchvg's picture
mitchvg's picture
mitchvg Saturday, 10 May 2014 at 7:50pm

Haha yes. But it's pretty hard to beat NNSW

Sheepdog's picture
Sheepdog's picture
Sheepdog Friday, 9 May 2014 at 3:46pm

"Sponger spots"? Is that some form of dermatitis?

mitchvg's picture
mitchvg's picture
mitchvg Friday, 9 May 2014 at 3:54pm

hahaha. yes, spongers are a dermatitis of the seabed.

Sheepdog's picture
Sheepdog's picture
Sheepdog Friday, 9 May 2014 at 5:25pm

"What's that on your inner thigh"?

"Ohhh, it's just a few sponger spots".

"Looks nasty...... Here. Try this"

"What is it"?

"It's canestin cream.... Great for fungal infections..."

"Gee, Thanks"..

"No worries.... Good luck with that...."

yocal's picture
yocal's picture
yocal Friday, 9 May 2014 at 4:08pm

Yes agree the overall swell size forecast for the GC was pretty spot-on. So it's a funny anomaly that the SF beaches are not pulling the modelled size, when at other times there is a huge size difference between exposed spots and points such as burleigh in a sth swell.
I guess the anomaly must be related to the variance in refraction rate of different swell size/angle/period/directons.

I much prefer to see the forecast for SF magnets than not though. Try to get maximum size potential out of each piddly little swell we get up here haha!

If you are having issues with people disregarding the difference between NF/open beach/SF magnets, I wonder if a simple change in colour would make the difference? Ie: make the NF/SF component a more transparent or 'greyed out' colour in the columns. Funny how the mind can play tricks on your perception.

Sheepdog's picture
Sheepdog's picture
Sheepdog Saturday, 10 May 2014 at 9:05am

Hmmm... I might have to do a "free ride"..... ;)

freeride76's picture
freeride76's picture
freeride76 Saturday, 10 May 2014 at 7:56pm

and there was plenty for all.

solo if you didn't mind a million duck dives.

Luckily the surf report was once again about as useful as tits on a bull.