Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Wed 23rd Aug)

Features of the Forecast (tl;dr)

• Small long period S swells glancing coast mid/late this week
• Poor quality S swell Thurs AM with lingering S’ly winds, tending variable in the a’noon
• Light winds now most likely for the weekend, NE in the a’noon
• Small swells both days with some long period S swell in the mix 
• E’ly winds early next week with building E-E/NE swells
• Possible large S swell later next week
• Potential for several E’ly swell sources next week- check back Fri for updates

Recap

S-S/SE swell held some fun surf yesterday with S facing beaches in the 3ft range, bigger by a notch on the Hunter with generally clean conditions through the morning and light onshore E-NE breezes in the a’noon. Size has dipped into today with size in the 2ft range at S facing beaches, 2-3ft on the Hunter and a bit NE windswell also in the mix. Clean conditions are on offer for the morning with a S’ly change moving up the coast and expected into Sydney by lunch-time (20 knot S’lies were observed at Montague Is by 8am).

Fun mixed bag this morning before the S'ly change

This week (Aug 23-25)

A cold front and long trough are bringing a S’ly change to the NSW coast, extending into the sub-tropics later today and overnight. There’s not a great deal of useful swell generating winds associated with the change so only modest short range S swells are expected  to accompany it. The lingering troughy pattern gets much more dynamic over the weekend as a powerful high approaches from the Bight. Storm force low pressure systems tracking under the continent are favouring Victoria for direct swell but we’ll see some long period swells refracting back into the Eastern Seaboard from these sources later this week and into the weekend. It’s quite a complex brew. Lets try and make some sense of it.

In the short run and lingering S’ly flow will likely leave some bump and wobble across most S facing beaches into tomorrow, with areas north of the Harbour most likely to get cleaner conditions under morning SW breezes. S’ly winds then tend S/SE before easing during the a’noon to light breezes, likely NE at most spots. Short range S swell of no great quality will be dominant to 2-3ft at S facing beaches, bigger by a notch on the Hunter and Central Coasts. There will be some long period S swells in the water although the majority of the energy is heading up the Tasman Pipe to Fiji and across to New Zealand. We should see a few 2-3ft sets from this source, possibly bigger 3ft+ at S facing reefs in the a’noon with deepwater adjacent to maximise swell focussing.

Short range S swell drops out on Fri with traces of long period S swell holding some inconsistent 2ft sets at the best swell magnets. Most beaches will be tiny. Clean conditions will be on offer under light NW winds, tending light N/NE in the a’noon.

This weekend (Aug 26-27)

A much more subdued outlook expected for the weekend with a coastal trough now either hovering just inland or retrograding back towards the Gippsland coast. That should see a regime of light winds for the weekend, most likely light N’ly breezes both days with morning offshore winds. 

Not much surf expected for Sat- just a tiny blend of S swells to 1-2ft at S facing beaches. Period charts do show some long period S swell glancing the coast later in the a’noon as a storm force low passes through Fri so it’ll be worth a squizz at S facing beaches, particularly deepwater adjacent reefs for a few sets, unlikely to exceed 2-3ft. 

Small again Sun, with another mixed bag of long period S swell glancing the coast and a small NE windswell signal. Again, not exceeding 2-3ft. A weak front passing into the Tasman early Sat may see some small S swell added to the mix later in the day but nothing more than 2ft. NE winds may tend more E/NE and freshen a notch into the a’noon depending on how the trough behaves. We’ll finesse that on Fri.

Next week (Aug 28 onwards)

Strong high pressure is slower moving than modelled on Mon but still expected to move east of Tasmania early next week. Models are in broad agreement that the trough line will remain inland (as opposed to moving offshore and forming a closed or diffuse low) so we can expect a freshening onshore flow from the E (E/SE-E/NE) and short range surf from the same direction, likely building into the 3ft range Mon and mixed with S swell generated from the deeper fetch passing through the Tasman. 

Onshore winds continue Tues with E-E/NE swell likely in the 3ft range.

We should see a shift in winds mid week as a trough/front approach from the W and high pressure moves across the Tasman. That should see winds shift W-NW on Wed with potential for fun surf from the E/NE.

Further ahead and models are hinting at something more dynamic later next week-although it is at the end of model runs and thus subject to low confidence. GFS is suggesting a front interacts with the lingering trough to form a low pressure trough in the Tasman and strong S’ly to SE’ly  fetch in the Tasman later next week with potential for large S-SE swell to develop.

EC is maintaining a more bog standard frontal intrusion but still offering potential for sizey S swell to develop Fri 1/9 or into the weekend.

There’s also lots of instability in the South Pacific window next week as troughiness potentially deepens and gets captured by the dominant high pressure cell. That may see a useful E’ly fetch develop SE of New Caledonia or further towards Fiji. Still a long way away so we’ll flag it for now and see how it looks on Fri.

Seeya then.