Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 16th June)

Best Days: Late Fri/Sat/Sun: large south swell but very windy at times. Mon: mix of E/SE and S/SE swells with improving conditions. Tues/Wed: fun small south swell with good winds. 

Recap: Slowly easing S/SE swell from Tuesday into this morning, with generally light winds and OK conditions. A minor, unexpected E/NE windswell perked up across a handful of exposed beaches mid-morning today, originating from a moderate but otherwise nondescript northerly fetch positioned well off the mainland. 

This week (July 17-18)

Today’s small mix of short range swells will ease further into Thursday and freshening westerly winds will effectively flatten a very lacklustre ocean. 

A vigorous cold front will then cross the coast early Friday morning, bringing south-westerly gales to most regions by mid-late morning (some locations - mainly north of Sydney - will see early W/SW winds). These gales are expected to develop across a broad region of the western Tasman Sea rather quickly, and in doing so will whip up a large south swell that’s due to peak on Saturday as the primary steering system - the Long Wave Trough - anchors itself across New Zealand longitudes. 

The most interesting aspect about Friday's outlook is the speed at which we’re likely to see wave heights ramp up across the coast. Early morning is expected to be very small (1ft south facing tops) but by mid-late morning there should be more visible 2-3ft sets and from then on the increase should kick in relatively quickly, with exposed locations likely to reach 6-8ft+ by the end of the day.

However, with gale force SW winds on hand you’ll have to tuck into a sheltered southern corner for the only rideable conditions. And bear in mind that the bulk of this size will push through really late in the day - so protected corners may not be worthwhile until mid-afternoon onwards.

This weekend (July 19-20)

We’ve got one major change for the weekend forecast since Monday's notes - removing the 6-8ft estimate and replacing it with 8-10ft+ for Saturday at south facing beaches.

Yes, this south swell is going to be very big but there are a few things I don’t like about it - mainly the position of the primary fetch, being located just off the South Coast. In fact the fetch is only modeled to extend south to about Tasmanian latitudes, which means that we’ll see a broad mix of swell periods all arriving at the same time, creating a very confused ocean. Add in a strong to gale force SW tending S’ly airstream and most locations will be a large, blown out mess on Saturday.

As such the best surf will be found at super sheltered locations that will be able to filter out the noise and make sense of the biggest swell trains (albeit at a much smaller size), so hopefully some of the less frequently surfed nooks and crannies will come to life up and down the coast. A slow easing trend is expected throughout the day.

Continually easing swells are slowly abating winds are expected Sunday but surf size is still likely to be well in excess of 6ft+ at south facing beaches early morning. Synoptic winds will also be out of the south at this time but a few select locations (i.e. Northern Beaches) may see an early period of SW winds. Once again protected southern corners will have the best options, and we’ll see a more pronounced drop in size during the day.

Next week (July 21 onwards)

The Long Wave Trough responsible for this swell event will slowly clear east of New Zealand early next week, and as a consequence our southern swell window will start to dry up. But that’s not before a polar low clips the southern Tasman Sea on Sunday, generating a smaller but long period south swell for later Monday and most of Tuesday (inconsistent 3ft+ sets at south facing beaches). This will replace a steadily dropping S/SE swell from the weekend's source.

Conditions will be better by this time but there’s still likely to be a lingering southerly flow on Monday, so early morning will probably haves the best options with a locally induced offshore breeze in many regions. Tuesday should see generally light variable winds as high pressure settles across the region.

Also expected in the water on Monday is a small E/SE swell generated by a secondary low just off the west coast of NZ’s North Island on Saturday morning. No great size is expected here but we might see some fun 2-3ft sets at times, which - mixed in with the easing S/SE swell - could create some fun beach breaks at those locations offering an early offshore wind.

We’re then looking at slowly easing long range south swell from Wednesday onwards, with no other long term swell sources on the charts. Tune in Friday to see if the weekend’s large south swell is still on target!