Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri Oct1 )

Forecast Summary (tl;dr)

• Small amounts of long period S swell in the mix Fri
• Better quality ENE swell Fri, holding Sat with a reinforcing pulse Sun and mostly offshore winds
• Final pulse of good quality ENE swell Mon, with good morning winds
• S  swell Tues PM next week, with a stronger pulse Wed
• Quick spike in NE windswell Thurs
• Solid spike in S swell likely either late Thurs PM, Fri more likely, holding Sat AM before easing

Recap

Scrappy, short period NE/ENE windswell has maintained fun but low quality surf on Thursday, with quality finally improving into today. Conditions were hampered by fresh N’ly winds yesterday with 2-3ft surf on offer for those not too fussy about quality. Some small amounts of longer period S swell were also in the mix and have continued into today with some 3ft sets at S facing beaches, though size was far from evenly spread. Conditions have improved into today, as the proximate band of N’ly winds begins to move offshore and local winds tend more NW, or even W. This is seeing better quality 3ft surf with some bigger, bomb 4ft sets at spots facing E. A fun way to end the working week beckons.

This weekend (Oct 2-3)

Nothing major to shift for the weekend f/cast. A very large area of high pressure covers the Northern Tasman adjacent to New Zealand, contiguous with an elongated area under Tasmania. A trough and inland low located over Victoria is now in the process of moving offshore, shunting the N’ly winds further East and bringing a regime of more variable, tending W’ly winds.

That’s good news for surface conditions over the weekend, with major chunks of both days seeing offshore winds. 

Surf-wise, swell from this current event has under-performed a notch and perusing ASCAT (satellite windspeed) passes has shown a more disorganised fetch and slightly lower windspeeds than model predictions. Nonetheless, there’s a nicely aimed fetch of ENE/NE strong winds located in the Northern Tasman sea into sub-tropical latitudes. That should see plenty of fun 3ft surf through tomorrow. Variable wind flow is expected to tend W’ly through most of the morning before a very weak S to SE flow kicks in, more prominent south of Jervis Bay, and likely to drop right out in the a’noon again. Should be no problem to rack up a couple of fun sessions through the day.

A little kick in size is still expected Sun, as windspeeds increase into the trough as it moves offshore Sat. That will bump period up a notch and produce a little more juice with some 3-4ft sets expected, more likely in the a’noon. 

A weak troughy feature brings a slight S’ly  component to winds on Sun morning, likely W to WSW through the morning, possibly enough to scuff up S facing beaches, before a light NE Seabreeze kicks in during the a’noon. 

Next week (Oct 4) and beyond

A broad area of troughy low pressure drifts south in the area East of Tasmania into early next week, before retrograding into the Southern Ocean. Winds tend NW to N’ly through Mon and with period bumping up due to gales feeding into the offshore trough/low over the weekend we're likely to see some great 3-5ft surf, with the maximum size more likely on the South Coast due to the fetch being better aligned for that coast. Expect size to tail off through the a'noon.

Frontal W’lies on Tuesday are likely to freshen ands with only leftover ENE swell on offer wave heights are likely to bottom out in the 2ft range. Gales are expected out of Bass Strait, but at the present the timing of this swell looks unlikely to arrive before dark on Tuesday. Small babyfood is on the menu Tuesday.

Things get more interesting on Wednesday. Frontal W to WSW winds tail off, with a clean morning expected and a refracted S swell pulse from the front pushing out of Bass Strait Tuesday and a slightly deeper, though weaker fetch under Tasmania. It’s not looking large by any means but S facing beaches should push up into the 3ft range during the morning. Winds are expected to tend N to NE and freshen as a high moves NE to be in the typical Spring sub-tropical position. 

An approaching front quickly tightens pressure gradients with the sub-tropical high, leading to a rapid escalation in NE winds overnight Wed and into Thurs before the front pushes into the Tasman, with good odds a robust surface low will form.

This pattern is likely to see an increase in NE windswell during Thursday, with a replacing spike in S swell late Thursday. We'll have a fresh look at NE windswell potential Mon, due to the very transitory nature of the fetch it's not likely to see much more than 2ft sidewinders. 

South swell is likely to be solid on Fri, as severe gales cover the central/southern Tasman sea. Expect S facing beaches to push into the 6ft range during Fri, with fresh WSW to SW winds expected. This spike then eases through Sat, with the low moving away quite rapidly after forming and a NE flow kicking in.

Troughy conditions continue into the medium term with more frontal activity pushing past Tasmania later next weekend suggesting more swell from the South into the week beginning 11/10. 

Check back Mon, with so much dynamic instability in the Tasman sea significant revision is likely.

Have a great weekend.