Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Wed Oct6 )

Forecast Summary (tl;dr)

• Leftover S swell Thurs AM with best winds AM before S'ly change
• Another spike in S swell Fri with less favourable winds, easing into Sat
• Small NE windswell Sun with an a'noon S'ly change.
• Dynamic pattern next week, trough/low expected to form in Tasman, with potentially large surf from Tues/Wed. Check back Fri for details. 

Recap

S swell pulses have come in close to f/cast expectations, allowing for the fact that these flukey S pulses can produce very different wave heights at different exposures and coastlines. Yesterday afternoon saw a nice pulse of 3ft surf, with generally clean conditions on offer. Clean conditions have extended into today with a generally offshore flow that has tended variable around lunch-tine with a NE Seabreeze. Size was in the 2-3ft range across a good chunk of the region, with some bigger 3-4ft surf on the Hunter and select S swell magnets. Surf size favoured Sydney and further North due to the fetch being located from Bass Strait Northwards.

This week(Oct 4-8)

We’re now well into the very mobile Spring pattern identified in Mon’s notes. Weak high pressure is currently over NSW and in the process of migrating into the Tasman sea and a series of fronts tied to a complex area of low pressure SE and SW of Tasmania are lined up to sweep across the SE of the continent and into the Tasman sea.

Current ASCAT (satellite windspeed) passes show the signature of the pattern with a fetch of mostly gale W to SW winds extending from Bass Strait into the Central Tasman Sea. This is supplying the current pulse of S swell with the next front close behind.

The mobile pattern sees residual S swell from todays pulse hold over into tomorrow with the high pressure quickly moving into the Northern Tasman bringing N’ly winds to the table. Get in early for the best winds with WNW to NW flow early before winds tend N’ly and freshen. A wind change is expected in the a’noon, likely SW for a brief period before a trough and rapidly building ridge sees winds swings S/SE and freshen. So early clean 3ft S  swell, bigger 3-4ft on the Hunter gets mauled by S/SE winds later in the a’noon.

Fridays S swell now looks a bit less glossy, courtesy of the lingering trough and high pressure ridge maintaining S/SE winds across the region.  The swell generating fetch is split into a Bass Strait fetch and a more distant SW fetch coming around the corner from Tasmania, with both a notch weaker and less favourable than the fetches responsible for the current round of S swell. So, Friday gets a downgrade, with surf in the 2-3ft range at S facing beaches, likely some bigger 3ft+ surf on the Hunter but marred by S/SE winds through the morning. The lunch-time to late session might be better value as winds lay down quickly, turn variable before tending NE and freshening through the a’noon. That at least opens up S facing beaches for the PM sesh. Lower expectations are now in order for Fri. 

This weekend (Oct 9-10)

Not a great deal of change expected this weekend compared to Mon’s f/cast notes. Sat morning early is probably the best bet with some small levels of leftover S swell available for the mop up session. 2ft sets at S facing beaches is likely to be the best of if, some 2-3ft sets on the Hunter, with an early NW flow quickly clocking around to the N then NE, as high pressure drifts off the Central NSW coast. 

Sunday looks a better bet for NE windswell , with the pressure gradient tightening overnight Sat and through Sun morning as a trough and front approach from the W. That sees N’ly winds freshen adjacent to the Central Coast, extending up to the Mid North Coast, and a developing NE windswell that should see surf in the 2-3ft range at E facing exposures during Sun. The trough crosses the coast sometime in the a’noon, bringing a vigorous wind change, likely SW to S, although a period of slack wind just before the trough is possible. That opens up the possibility of some clean side-winders Sun PM around the wind change for the savvy operator.

Next week (Oct 11) and beyond

Models are starting to take shape on the pattern next week, which is highly unstable and dynamic, so we’ll definitely need to revise these calls on Fri, and probably Mon as well. 

A front passes into the Tasman Sun, producing a small pulse of S swell Mon, likely not much of a surf producer due to strong S to SSE winds along the  Southern and Central NSW coast.

The major feature of interest is then an offshore trough. Models still differ on the location of the trough, which will have a major bearing on the surf potential for different regions next week.

GFS places the trough just off the Central/Hunter coast, with onshore winds increasing south of the trough axis, leading to a fast rising stormy swell during Tues.

A coast-hugging surface low forming in the trough line has potential to then generate large surf for the region during Wed, possibly extending into the latter part of next week, depending on the position, strength and movement of the low.

EC model has the trough located much further North, off the Mid to North Coast, with the focus of larger surf on the area just to the south of the low. Prior to that EC also invigorates the Sun/Mon front into a deep low near the South Island on Mon, with a possible strong SSE pulse for Wed/Thurs.

Developing moderate size E swell is likely from this scenario later next week, with the low then drifting towards New Zealand and aiming up another fetch of E’ly winds towards NSW late next week, suggesting E swell into the weekend of 16/10.

In short, our active Spring pattern continues, with firming odds for plenty of surf from mid-next week and conditions dependent on whether you are north or south of the trough/low axis.

Check Fri and models should be starting to settle on an outcome for next week, which will give us some certainty on the calls.

For now, there’s one more small S swell pulse to surf and some leftovers to mop up.