thermalben

Extended period of solid NE swells ahead, with pockets of good conditions

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 12th December)

Best Days: Fri: peaky, easing NE swell and a small SE swell, with mainly light variable winds. Sat/Sun: stacks of NE swell but problematic winds. Likely persisting (though easing surf/wind) on Mon. Tues onwards: more S/SE swell, and a possible NE cyclone swell, plus some small E/NE trade swell. Unlikely to see small conditions for some time.

Recap: Small, easing NE swell over the last few days with tiny conditions now prevalent across the coast. Winds have been mainly light. 

This week (Dec 13 - 14 onwards)

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We've got lots of swell ahead this forecast period, with a broad, complex trough expected to occupy the eastern states for a few days under a regional blocking pattern.

Thursday will initially start off small, with NE winds freshening throughout the day, building NE windswells across the coast. Before I get into the details about the evolution of that event, we need to acknowledge a small SE swell that’s due to build through Thursday, peaking late afternoon or early Friday, originating from a small Tasman Low that migrated towards New Zealand over the last few days.

The models don’t like this system much, but I think it’ll be OK, peaking somewhere between 2ft and maybe 3ft at reliable south facing beaches, mainly across the Hunter, biggest for the late session Thursday or the dawn patrol Friday. 

Thursday’s NE fetch will concurrently build a local windswell that’s expected to peak on Friday. However, the associated complex trough over the eastern states is expected to throw a bunch of curveballs our way, the first of which is an eastward extension over the coast and out into the Tasman Sea on Friday, shunting the fetch further away from the mainland - if anything slightly outside of our prime short range swell window.

It won’t have a dramatic effect on our surf potential - we’ll see a morning peak in size, and then a slow decrease into the afternoon, but northerly gales off the Mid North Coast will keep the coast active throughout the day - however it should alter the local wind outlook, offering periods of variable winds across the coast. 

Bearing in mind that ‘variable’ means ‘from any direction’, there’s obviously a chance that we could see onshore and thus bumpy conditions at some locations. But for the most part I think we’ll see favourable surf at many coasts, with a reasonable chance that the variable pattern will at some point also swing offshore. My glass is very much half full for Friday.

As for surf, Thursday should build from a very small start, up into a bumpy 2-3ft at NE facing beaches by late Thursday, and Friday is expected to ease from an early peak around 3-4ft, back down to 2-3ft throughout the day. Of course, this NE swell will be much smaller at south facing beaches but they’ll see small inconsistent lines from the aforementioned SE swell too.

This weekend (Dec 15 - 16)

So, the weekend’s forecast has been scaled up a little since Monday's notes were issued.

We’ll be under a synoptic blocking pattern throughout this period, and although actual wind speeds within our swell window won’t be amazingly strong - worthy of perhaps 3-4ft surf under a typical two-day strengthening pattern - their longevity in a stationary position will ensure we see more size than what's normally expected. 

However, the broad inland trough is also expected slide its eastern extension back onto the coast during Saturday which will bring fresh to strong NE winds back across most coastal areas both days, reaching a peak on Saturday. So, conditions will be pretty ordinary at most beaches though there’ll be good options at protected locations.

As for size, it’s still little early to have total confidence (considering how much things have evolved since Monday) but it’s looking like Saturday will build into the 3-5ft range at NE facing beaches, and further to 4-5ft, maybe 4-6ft on Sunday. Larger surf is expected along the South and (especially) Far South Coasts, due to a longer fetch length, and stronger winds at the head of the fetch too - but local winds will be an issue here as well.

Of course, south facing beaches will be much smaller each day, as will other poorly aligned coasts such as the Northern Hunter. Friday's SE swell will be tiny by that afternoon and will be completely gone by the weekend.

There is a chance we’ll see brief, isolated pockets of OK conditions across one or two coastal regions over the weekend, but it’s likely to be the exception rather than the norm (compared to Friday, where we should see the balance tip greatly in our favour in many regions).

Next week (Dec 17 onwards)

Sunday’s fetch will hold into the evening before weakening into the start of next week, which means strong swells holding into Monday morning, though easing throughout the day. Early sets may be around the 4-5ft or 4-6ft mark at NE facing beaches (smaller at south facing beaches), easing to 3-4ft throughout the day. 

Local conditions look tricky but there’s quite a bit of potential, thanks to the weekend’s inland trough forming a closed low in the Southern Tasman Sea. This will extend a surface trough into Southern NSW; current modelling has it south of the Illawarra on Monday (i.e. with moderate N/NE winds across the Illawarra, Sydney and Hunter coasts) but we are likely to see revisions over the coming days. Either way wind speeds will be easing from the weekend.

A return southerly swell (from the new low in the Southern Tasman Sea) and an associated southerly change is expected on Tuesday, though no great size is expected at this stage - enough to fire up south facing beaches with 3ft+ sets through into Wednesday but current expectations aren’t high for anything amazing.

Of much more prominence is TC Owen, currently in the Gulf of Carpentaria but expected to recurve back over Queensland before positioning itself off the SE Qld coast early next week.

At this stage TC Owen may end up hanging a little too far north, and a little too close to the coast to be a significant influence for us - compared to SE Qld and Northern NSW, but it’s still likely to generate some decent NE swell through the middle to latter part of the week. Swells from this region (and this direction) are often pretty steep though so usually only favour very well exposed locations, mainly south from Sydney. However it’s certainly got the potential to be upgraded in future model updates (by way of an easterly relocation, into a better part of our swell window). I’ll be keeping a close eye on that. 

Looking elsewhere, and the aforementioned Southern Tasman Low will likely remain a source of (probably small) SE swell later next week and into the weekend, whilst a decent fetch of trades north of New Zealand from this Sunday onwards will generate small but useful E/NE swell mid-late next week too.

So, there's stacks of surf ahead! See you Friday. 

Comments

Westofthelake's picture
Westofthelake's picture
Westofthelake commented Wednesday, 12 Dec 2018 at 6:36pm

Some good news right there.
The life cycles of cyclones never cease to amaze me.

thermalben's picture
thermalben's picture
thermalben commented Wednesday, 12 Dec 2018 at 7:58pm

Interesting wind outlook from the BOM for Friday: "Northeasterly 15 to 25 knots." Quite the contrary to my notes. All models have generally light winds, in fact GFS actually has an early W/SW flow at 10-15kts across the Illawarra. 

getwet's picture
getwet's picture
getwet commented Wednesday, 12 Dec 2018 at 8:50pm

"Stacks of surf ahead" is the forecast I want to hear leading into Christmas. Can't wait to get into it

stunet's picture
stunet's picture
stunet commented Wednesday, 12 Dec 2018 at 8:59pm

Dynamic synoptics give me that soul kind of feeling.

davetherave's picture
davetherave's picture
davetherave commented Thursday, 13 Dec 2018 at 7:59am

stu- nice work there, but corny, movin to the beat!!!

davetherave

Lakemac's picture
Lakemac's picture
Lakemac commented Thursday, 13 Dec 2018 at 6:12pm

Haha settle down swellnet. Cannot believe the hype on this one! Is this a piss take? I support surf forecasting, it’s difficult, but seriously?

thermalben's picture
thermalben's picture
thermalben commented Thursday, 13 Dec 2018 at 6:35pm

How can you comment on the forecaster notes when you’re not a subscriber and thus can’t read what was written?

barrel_pig's picture
barrel_pig's picture
barrel_pig commented Friday, 14 Dec 2018 at 5:27am

Where's the hype dude? I read this report and booked in a full week of work. The forecast is for waves, with low expectations on good winds (Iikely junky).

Lakemac's picture
Lakemac's picture
Lakemac commented Thursday, 13 Dec 2018 at 6:49pm

Read it at the pub this arvo. Don’t get defensive, you have to admit it is a bit funny.

thermalben's picture
thermalben's picture
thermalben commented Thursday, 13 Dec 2018 at 6:59pm

Where’s the hype mate?

C’mon, fair play. I’m happy to accept criticism of the forecast when it’s wrong (which to date, it hasn’t been) but in any case the general tone of the forecast suggests crappy conditions just about everywhere.

It’s also worth pointing out that we also had haven’t issued a swell alert for this event, anywhere on the East Coast.

boxright's picture
boxright's picture
boxright commented Friday, 14 Dec 2018 at 7:56am

"read it at the pub this arvo"

Classic. Right after the dog ate your homework, right?

thermalben's picture
thermalben's picture
thermalben commented Friday, 14 Dec 2018 at 5:45am

Bummer.. the NE windswell peaked a little earlier than expected (just before midnight) and has been easing for the last six hours, so it's smaller than expected this AM (buoy data is down around half a metre, from the 11:20pm peak of 1.82m HSig).

However, it's nice to see light variable winds (anywhere from the S through W/NW) this morning. BOM still forecasting 15-20kt NE winds for some reason.

thermalben's picture
thermalben's picture
thermalben commented Friday, 14 Dec 2018 at 7:09am

A bit slow but still looks super fun with 3ft sets on offer.


thermalben's picture
thermalben's picture
thermalben commented Friday, 14 Dec 2018 at 2:01pm

'Giant hail stones' is not common terminology.