Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 15th Aug)

Forecast Summary (tl;dr)

• E-E/NE swell perks up Mon, persists at small levels Tues-Wed then builds Thurs as “trough block” forms in South Pacific slot
• Chunkier E/NE swell likely Fri from "trough block" fetch persists through Sat/Sun, easing Mon
• Flukey small S groundswell Mon/Tues- only showing at reliable S swell magnets
• Slight kick in short period S swell Wed
• Small/mod S swell likely Sun/Mon
• Long range E swell builds in next Tues
• Active period of S swell pulses likely from next Wed as frontal progression enters the Tasman.

Recap

Not much on offer over the weekend, just clean babyfood both days, marginally bigger Sun for most of the region, bar the Illawarra, which missed the marginal increase in E/NE swell. Size has perked up a notch today with clean 2ft sets around from the eastern quadrant, mostly mid period swell from the Coral Sea, with a few stray long range sets from a long range E swell. Clean conditions under W to NW winds. We’ve got a few small days ahead before a more dynamic period later in the week.  Details below. 

Bit of a wait but some fun ones when they come

This week (Aug 15-19)

Remarkably there is little change to the current synoptic set-up which was forecast a week ago by weather models. A deep low just to the East of Tasmania is now slowly weakening and moving away, maintaining a westerly flow across the region. A trough line linked to the low extends from the Tasman Sea up into the Coral Sea past New Caledonia and over the next few days this trough deepens as it slowly moves East, activating an incredibly wide fetch of E to NE winds infeeding into it. We’re still looking good for a few days of quality surf from this source late in the week and into the weekend. A mid week pulse of S swell is also on the cards as a thin fetch quickly sweeps up the NSW Coast before another round of W’ly dominated winds.

In the short run and we’re looking at another small, clean day tomorrow as a mix of E swells continues to supply sets to 2ft under a mostly W’ly flow which will tilt more SW in the a’noon as a front passes into the Tasman. If you found a bank today then repeat the dose for tomorrow. 

The cold front drives a thin fetch of SW-S winds along the coast Wed, which will make conditions unattractive at S exposed breaks. That fetch will whip up a small amount of short range S swell through the day, topping out at around a windy 2-3ft at S exposed breaks. Small E swell offers better surf at more protected locations and that signal will maintain some 2ft sets through the day, albeit a bit slow and inconsistent. 

By Thursday we’ll see the ocean start to show more energy from the E-E/NE as the trough block swell starts to show. Winds look pretty good. Weak high pressure off the Mid North Coast and an approaching front should see a NW flow with a light NE seabreeze. Through the morning expect undersize 2ft surf- mostly E swell with a small amount of leftover S swell- but through the day surf should muscle up a notch to a fun 2-3ft.

Friday is still looking really good. As we said last week, the distance of the trough block from the East Coast will limit swell size, compared to last July’s episode but we’re still looking at really good quality 3-5ft surf through Fri, with a few bigger 4-6ft pulses possible at exposed breaks. A front sweeping through the interior brings all day W’ly winds, possibly tending more W/SW to SW late in the day as the front migrates Eastwards. Pencil in Friday.

This weekend (Aug 20-21)

Complicated weekend f/cast with plenty of swell on tap.

Expect some revision through the week with a cold front passing through Sat, seeing winds swing SW. Good quality E swell from the trough block holds size in the 3-5ft range. A late kick in new short range S swell is expected from the proximate fetch of SW-S winds off the NSW Coast, which will add some 3-4ft of short range swell to S facing beaches.

The front moves away overnight Sat, leaving a lighter SW flow Sunday morning that will shift to light SSE-SE breezes through the day.  Good quality E swell eases back a notch into the 3-4ft range and stronger S swell from a parent low tracking NE next to Tasmania early Sat supplies 3-4ft of S swell, bigger 4-5ft on the Hunter. Expect a bit of leftover lumpiness from Saturdays S’lies but there will be plenty of size and juice about.

Next week (Aug 22 onwards)

Into next week and the trough block swell slowly eases into Mon with some 4ft sets on offer under offshore conditions as a major frontal progression approaches from the Southern Ocean.

Following that swell is another long range E swell, generated by an intense low pressure system retrograding through the South Pacific from Wed-Fri this week (see below). Although this system isn’t perfectly aimed at the Eastern seaboard the strength of the winds, length of the fetch, and movement back towards the coast should see some strong 4ft sets start to build Tues with continuing offshore winds.

From mid next week we’ll be turning eyes back to the south as a major frontal progression/cold outbreak and deep polar lows enter the southern swell window. 

Models are still offering mixed messages but the basic pattern suggests some strong S swell pulses from Wed next week. We’ll flag those for now and drill down into specifics this week as model guidance becomes clearer.

Check back Wed for the latest update on what is shaping up to be an active period of good waves.