Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Wed 18th August)

Forecast Summary (tl;dr)

• Solid S swell Wed, easing through Thurs, with winds tending N’ly and freshening
• Small S swell pulse Fri, easing through Sat
• Complex pattern next week: Long range E swell likely from Thurs
• S swell pulses next week, Tues/Wed and Fri, stay tuned for details.

Recap

Strong S swell has been on the menu with a fairly typical spread of wave heights across the region for a directional S swell. Yesterday saw Newcastle pick up the lions share of an initial pulse with 4-5ft surf reported, grading smaller 2-3ft in Sydney. Wave heights kicked overnight and a much stronger signal is in the water today with swell periods up in the 12-13 second band, 6-8ft surf across the Hunter, with a smaller but still strong 4-5ft S swell running in Sydney. Conditions were clean but there was some left over surface bump from S’ly winds yesterday, more pronounced on the Hunter with it’s more S’ly tilted coastal alignment. Strong surf at S exposed beaches is expected to slowly tail off through the evening, with a slow easing trend continuing through Thurs.

This week (Aug 18-20)

We’re past the peak intensity of the current low transiting the Tasman sea but the current ASCAT (satellite windspeed) passes still show a very long fetch of mostly strong winds extending from 50S  with the head of the fetch adjacent to central NSW latitudes (roughly Newcastle). That fetch will maintain a slow easing S swell through tomorrow with a further easing into Friday. 

Surf size is expected to slowly drift down from 3-4ft tomorrow, 4-5ft on the Hunter, back into the 3ft range in the a’noon and further down into the 2-3ft range Fri morning, likely bottoming out mid morning to mid a’noon in the 2ft range.

With high pressure now nosing into the Tasman and moving east of NSW later today, light and variable winds through today will start to tend N’ly through Thurs and Fri, freshening tomorrow before a shallow troughy pattern on Fri sees winds tend more NW, or even WNW. That lends confidence for plenty of fun surf for the rest of the working week if you can get on the right side of N’ly component winds. 

Friday offers potential for  little bump in size during the late a’noon, courtesy of a smaller, compact cold front and low passing well to the south of Tasmania overnight and transiting the far-southern Tasman through tomorrow. It’s not an especially big system and it intensifies a bit too Far East in the swell window with source winds aimed at New Zealand targets to be a major swell producer. Nonetheless, swell radiating away from the source fetch, from the SSE direction, may show very late Fri, though it's likely to arrive after dark.  Worth a look on late on Fri a’noon if you’re lucky enough to have a S swell magnet at your disposal. 

This weekend (Aug 21-22)

Small S swells are still the main course this weekend with winds looking OK at this stage. Friday's late arriving small SSE swell should hold into Sat morning with some slow but fun 2ft sets at S facing beaches, 3ft surf holding on the Hunter. As we run up to the weekend full moon the evening tides will get much bigger so the smaller morning tides will likely be much more suited to the small amount of energy on hand. The weak, troughy pattern, typical of early Spring should see a light morning northerly component land breeze tend to weak seabreezes. 

Sunday looks smaller and weaker now compared to Mon’s notes. A weak front pushing past Tasmania on Sat is now expected to be mostly NW in direction and this is not expected to be much of a swell source for NSW. Expect some clean babyfood Sun morning in the 1-2ft range, 2ft on the Hunter with freshening NE winds in the a’noon probably better suited for kiteboarding than surfing.

Next week (Aug 23 and beyond)

Next week looks really active now, with a few different swell sources in the offing and a fair bit of model divergence, which is likely to see substantial revision on Fri. 

Lets look to the east first. The deep E’ly fetch we identified last Fri is now back on the books. Both major weather models are now interested in a large high becoming slow moving just on the Pacific side of the North Island from this weekend (21-22 Aug). A long, broad fetch of ESE/SE winds develops along the northern flank of the high, filling out that very favourable South Pacific corridor between the North Island and New Caledonia with strong winds. 

Model diverge is still significant, GFS develops a low or trough/dip on the flank of the low with a major ramp up on windspeeds, while EC has a much more modest but still impressive tradewind fetch through the early part of next week. 

We’ve got enough info now to start blocking out the second half of next week, likely from Thurs but possibly late Wed for a prolonged E’ly swell event. Nothing massive due to swell decay from the long travel distance but potentially 3ft from the EC scenario or 3-4ft from GFS. Heads up, check back Fri for further details.

Now to the south. 

Plenty of action next week as the Southern Ocean maintains a very active late Winter storm pattern. N’ly winds increase Mon with potential for a small round of NE windswell during the day.

These winds get cleared out by a SW’ly change Tues as a strong front pushes well up into the interior of NSW, potentially spawning a small surface low that tracks away quickly to the E.

That suggest a moderate spike in S’ly swell later Tues, easing Wed. 

A much more significant polar low then tracks into the Tasman either later Wed or Thursday with gales and severe gales extending from 55S up to Tasmanian latitudes. Strong S swell pulse is likely to be generated by this fetch. A high at Tasmanian latitudes then drives S’ly winds up the coast, with potential for SE windswell to develop Fri 27.

It’s a complex brew of overlapping swell trains from the E and S and lots of wind changes ahead. 

Check back in Fri and we’ll run the ruler over it with fresh eyes. In the meantime hope everyone is getting a few sanity saving surfs in.