Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri Nov 19 )

Forecast Summary (tl;dr)

• Small mix of swells Sat with light winds early tending S then E/SE through the day
• Increase in stormy E'ly swell Sun with freshening onshore winds
• Large E to ESE swell Mon, with fresh onshore winds expected
• Decreasing E'ly swell Tues with onshore winds easing
• Likely building NE swell Wed PM, peaking Thurs, easing Fri
• S swell on the cards for next weekend but low confidence in f/cast, check back Mon

Recap

Leftover S swell provided a few fun waves yesterday, particularly at notable S swell magnets like the Hunter Coast, which saw 3ft sets, smaller 2-3ft at S facing beaches elsewhere in the region. Light morning NW breezes provided clean conditions before winds kicked up from the NE. That swell source has dried up today, leaving behind a small E to NE signal, topping out at 2-3ft on favourably angled coastlines like the Northern Beaches, but generally smaller 2ft elsewhere. Flukey winds around a developing trough line are blowing anywhere from W/NW to N to NE throughout the region.  A very complex, dynamic pattern is currently unfolding, so lets dive in and try and make sense of it.

This weekend (Nov 20-21)

The pattern as we described it on Wed remains fundamentally the same, but the position of the moving parts has shifted so there’s some significant changes to the weekend f/cast.

Sat remains on the small side. A weak front passed into the Tasman today, along with a patchy fetch of sub 20 knot winds feeding into the developing trough and some leftover NE windswell. All those small swell trains are expected to be in the sub 2ft range through most of Sat. If the trough behaves as forecast we should see a variable/light SW flow early before winds tend more S’ly through the day, likely ending up E/SE in the a’noon.

Be prepared for some variability in wind flows and directions due to the trough but as a general rule, early is best. 

Sunday is a different beast and amazingly, a day out, still subject to model uncertainty with widely differing plausible scenarios. It hinges on an approaching inland low. Previous model runs had the low exiting the Far South Coast on Sun, with a fetch largely located too far south to generate much swell for the region. 

Current model runs suggest the low is further north, and unlikely to exit the coast until late Sun evening or even early Mon. 

A major spanner in the works is EC, one of the most reputable global weather models, now predicting the low to “wash out” in the interior, and not exit the coast. 

Given that uncertainty and the likelihood of large error bars in the f/cast we may need to revisit calls over the weekend.

It’s likely we’ll see increasing onshore E’ly flow either way, as infeed into the interior low picks up Sunday.  Anyway we slice it Sunday is unlikely to be pretty, with a fresh onshore flow that could vary from E/NE to SE depending on the position of the interior low as it approaches the coast. 

With high pressure East of Tasmania supplying the infeeding winds, it’s likely to see a steep increase in local E’ly quadrant swell through the day. 

How big? As a ballpark figure it’s likely local short period swell will build into the 3-5ft range during the day. Possibly bigger 4-6ft in the south of the f/cast region. Quality will likely be impacted by onshore winds, with sheltered spots the only surfable options.

Again, this is highly contingent on the position of the interior low and the strength of the infeed, both of which are still in question.

Stay tuned for updates over the weekend in the comments.

Next week (Nov22) and beyond

Dominant high pressure sits just East of Tasmania by Mon next week, directing a strong E’ly flow, likely enhanced by the remnants of the interior low sitting off the Central/Mid-North NSW Coast. Expect strong SE/ESE winds through Mon and a large, local ESE swell. Not quite victory at sea, but not far off. With plenty of size on offer, likely in the 6ft+ range it’ll be surfing at sheltered spots only, with smaller size on offer. 

A roll-off in size is expected through Tues as the trough/low dissipates, with size likely to ease back into the 3-4ft range during Tues. No let up in the onshore flow though, with straight E to ENE winds expected.

There’s no let up in the troughy pattern with the second half of next week seeing increasing NE winds, as the pressure gradient is tightened on the western flank of the dominant high by (yet!) another complex trough system approaching from the interior. 

That’s offers good odds for increasing NE windswell, from Wed PM, building further into Thurs. Size is likely to build into the 3ft range Wed, rising further into the 3-5ft range Thurs.

By the end of next week a strong frontal system approaches from the Southern Ocean, driving further instability along with the interior troughs.

A S’ly change is on the cards for Fri next week, with potential for a solid boost in S swell next weekend 27-28/11. That could take various forms- once again models are all over the place. The frontal progression below Australia is likely to produce some longer period S’ly swell.

An elongated trough line through the Tasman, may spawn a low East of Tasmania next weekend or generate a broad wind field of SSE winds through the Tasman. 

Confidence is extremely low this far out due to the extreme instability in the synoptic pattern, we’ll monitor over the weekend and report back Mon with a full update.

Until then, have a great weekend.