Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 31st January)

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thermalben started the topic in Friday, 31 Jan 2014 at 12:25pm

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 31st January)

Best Days: Monday: could be some inconsistent but fun waves from an E’ly swell. Also worth pencilling in next Friday for a decent SE groundswell.


There’s been a steady supply of mainly weak, peaky but generally fun NE windswell over the last few days. Wave heights were slightly above model forecasts, hovering in the 2-3ft range at most beaches open to the NE (with smaller waves at south facing beaches). Winds have been mixed, usually light in the mornings and freshening throughout the day time but there have been isolated instances of LAGOS. 

This weekend (Feb 1-2)

We’re not expecting much surf over the weekend. The existing short range NE windswell should continue to trickle in but the source of this activity is drying up, and expected to be all gone by Saturday morning. There’ll be some lingering minor swell activity on Saturday but it’ll fade into the afternoon and further into Sunday

Winds will be mainly moderate onshore throughout this period but periods of light variable winds are possible thanks to the presence of a weak trough cover the southern half of the coast. There’s some model divergence in the winds just offshore from Saturday night - our forecast graph is underpinned by the GFS solution which maintains weak wind strengths into Sunday (and consequently keeps wave heights in the 1ft range). However the European solution freshens this NE flow into the 15-20kts which - if it happens - should result in some 2ft sets at NE facing beaches at times on Sunday

Anyway keep your expectations low as local winds will probably spoil the party in general. 

Next week (Feb 3-7)

There’s an impressive low pressure system currently north of New Zealand, which looks quite good on the synoptic charts. Indeed, the OSCAT satellite returns are showing a reasonably broad area of 50kt E’ly winds near 31S, 178W - winds of this strength are not especially common in this neck of the woods, and if positioned in the right environment has the potential to generate large swells with long periods. These winds are also marginally higher than what the computer models were estimating (so, we should adjust the swell output correspondingly). They’re also more E’ly in direction (model forecasts have a SE direction). 

However there are a few factors working against the East Coast’s swell potential from this system. Firstly, the low is a very long way from the mainland. Secondly, it’s tracking slowly south/southeast, which is perpendicular to our swell window. Thirdly, the fetch is about to slip into the swell shadow of New Zealand’s North Island - at least with regards to the southern half of New South Wales (it’s still somewhat exposed to the Northern NSW and SE Qld coasts). And fourthly, the majority of the existing (and forecast) fetch is SE in direction, aimed up into the Coral Sea, so we’ll mainly see sideband energy glancing the southern NSW coast. 

Still, it’s hard to ignore the strength and size of this low. And although it’s moving unfavourably S/SE, this forward track is very slow. So, it should kick up a reasonable groundswell event that is estimate to make landfall in the early hours of Monday morning.

How much size will we see? Overall, the North Coast will see the biggest surf - but no matter where you are positioned, set waves will be VERY inconsistent. Maybe 15-20 minutes between the bigger waves. So, you’ll need to be patient. However we’re looking at more size than our model is forecasting; I think it’s not unreasonable to see 2-3ft sets in the southern half of New South Wales at times. But between these set waves it’ll be much smaller (1ft). And winds will be mainly moderate NE (lighter in the morning) so certainly don’t expect perfection.

Monday’s swell should peak around lunchtime, and then slowly ease from Tuesday onwards. We’ve got a gusty southerly change due sometime throughout the day (not certain on timing.. model data is split between an early morning and an early afternoon arrival). Either way we’ll see a punchy short range south swell fill in behind the change; it should be sufficient for a solid late increase at south facing beaches but we’ll re-evaluate this in more detail on Monday.

This south swell should hold into Wednesday morning but will ease during the day and winds look like they’ll be mainly SE in the wake of the change (although local areas of early SW winds are possible). Smaller residual swells are expected on Thursday.

Looking further ahead, and there’s some really interesting model data showing up for the Tasman Sea during the middle of next week, which could give rise to a quality SE groundswell on Friday. Following Tuesday’s southerly change, it appears that a decent cut-off low will form just west of the SW tip of New Zealand’s South Island later Tuesday and into Wednesday. There’s good agreement between the models that such a scenario will eventuate, but we’ll have to wait a few more days before firming up the specifics regarding size/strength/timing etc. Either way, I would highly recommend pencilling in Friday for a decent round of waves right across the southern NSW coast. More on this in Monday’s update.