Troughy pattern to bring waves all week

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 1st December)

Best Days: Wed/Thurs/Fri: good NE swell with favourable winds. 

Recap: Plenty of south swell over the weekend (strongest Saturday, easing Sunday), with some small NE swell too. Winds were light N/NW in the mornings offering clean conditions before the obligatory nor’easter cropped up in the arvo.

This week (Dec 2nd-5th)

Today’s quality south swell will ease slowly over the coming days, allowing a building short range NE windswell to become the dominant force.

In fact we’re looking at a persistent pattern of NE windswell and funky winds right up until the weekend, all thanks to a broad, slow moving trough across the region. 

There’ll be thunderstorms in and amongst the mix every day (usually the afternoons) but these should be leveraged for their benefits; that is their ability to disrupt the synoptic NE flow and briefly divert winds offshore, creating small windows of clean surf.

Wave heights should build overnight tonight, and we’re looking at 3-4ft surf at NE facing beaches throughout Tuesday and possibly even Wednesday. However, the main difference between the two days are the local winds. 

This afternoon’s NE winds are already trending N/NE and should go N’ly overnight and early morning. They’ll remain light to moderate in strength early on but will swing NE at some point mid morning and really kick up into the afternoon, rendering most beaches quite bumpy. The early session will still have some wobble - not quite as much - but it’ll certainly be the best time to surf.

During the day, a weak trough is modelled to move along the South Coast (with an associated S’ly change), possibly forming a microscale low between Sydney and Ulladulla. This may cause a moderate S’ly wind change about the Illawarra and Sydney and coasts overnight and into Wednesday morning, but a more likely scenario is a period of light variable winds before a return to freshening nor’easters during the day.

So - this certainly favours Wednesday morning for a few hours of really decent waves across most beaches open to the north-east. 

Beyond this, we’re looking at the persistent NE fetch retreating a little further offshore through Thursday and Friday, but still supplying good energy to the region. In fact the European model is suggesting we could see similarly sized surf from the NE through Thursday morning, but there’s not a general agreement between the models right now so it may end up coming in a little smaller. 

Wind wise, the threat of nor'easters is possible from Sydney northwards (although periods of NW winds are also on the cards, especially early). South of Sydney we’ll probably be into a light variable pattern Thursday ahead of a moderate to fresh southerly change Friday, extending northwards and reaching Sydney late in the day, of which winds will probably be N’ly or NW ahead of the change. We’ll really need a few more days to pin down the specifics though.

This weekend (Dec 6th-7th)

These troughy patterns are hard to have confidence in at medium or long range, so the weekend forecast is somewhat of a fence-sitter right now.

That being said, as a bare minimum I think there’ll be enough residual NE swell to offer something rideable both days.

In fact such troughy patterns are susceptible to rapid bouts of computer model intensification (read: short term forecast upgrades). So, I’m reasonably confident that - despite the weekend’s charts remaining relatively benign right now - we could end up seeing something of much more substance develop over the coming days. Stay tuned.

Long term (Dec 8th onwards)

As per the weekend’s notes, we need a few more days to firm things up but there’s a lot of complex weather activity lining up across our near swell window into the long term, all of which suggests plenty of surf through next week. More on this in Wednesday’s update.


thermalben's picture
thermalben's picture
thermalben Monday, 1 Dec 2014 at 5:23pm

Jeez, how's the BOM's 'swell' forecast for Wednesday. Not so much the size (which is an undercall anyway), but the specific directions:

"Northeast to southeasterly around 1 metre, tending east to northeasterly 1 to 1.5 metres during the morning, then tending easterly around 1 metre by early evening."

thermalben's picture
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thermalben Tuesday, 2 Dec 2014 at 2:28pm

"There’ll be thunderstorms in and amongst the mix every day (usually the afternoons) but these should be leveraged for their benefits; that is their ability to disrupt the synoptic NE flow and briefly divert winds offshore, creating small windows of clean surf."

Classic example of this on this on the Northern Beaches this morning. Got a soaking just before dawn (13mm in 2.5 hours at Terrey Hills): fresh, gusty N'ly winds preceded the rain but as soon as the system pased winds went light NW for a few hours (7am - 9am, according to North Head AWS). Soon followed by nor'easters late morning that are now gusting 20kts again.

Keep an eye on that radar! A few cells are popping up over the ranges and should move west over the coming hours. A few areas could experience a late glass-off.

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thermalben Wednesday, 3 Dec 2014 at 3:58pm

Incoming again! Lots of cells pushing across southern NSW right now. 'Bout to smash the South Coast too.