Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 28th Aug)

Features of the Forecast (tl;dr)

• Long period S swell pulse peaking Mon, easing slowly Tues with developing N’lies
• Small mixed bag of leftover S and potential NE windswell Wed with NW winds early tending mod/fresh N-NE in the a’noon
• Continuing small mixed bag Thurs with light winds (depending on trough)
• Low pressure trough likely to form in Tasman Fri with increasing S’ly winds and swell
• Plenty of S swell likely Sat with SW-S winds
• S swell likely eases Sun with offshore winds
• Pulses of SE-E/SE swell on the radar next week as low drifts near NZ
• More S swell in the medium term

Recap

More swell from the S over the weekend with Sat seeing the smallest surf- around 1-2ft tops at S facing beaches and mostly light/variable winds. Sunday saw a very inconsistent long period signal which offered up a few clean 3ft sets under similar light winds. Today has seen a reinforcing signal of S swell with long lines to 3-4ft at S facing beaches on a building trend and first class conditions under light W-W/NW winds which will trend N-NE through the a’noon. 

Another pulse of long period S swell makes landfall on the Hunter

This week (Aug 28- Sep 1)

We’ve got a reasonably strong high (1032hPa) sitting in the Tasman, slowly drifting NE and weakening as it does so over the next 36-48hrs with the last of a series of powerful storms tracking across the lower Tasman. In the absence of a high pressure ridge we’ll see increasing N’lies across most of the Eastern Seaboard from temperate to sub-tropical regions. A trough will extend along the East coast before a front through the latter half of the week brings vigorous S’ly winds by Fri. The trough is expected to move offshore and merge with a more tropical derived depression to form a large trough of low pressure in the Tasman over the weekend. This has been a feature of synoptic prognostic charts for a few weeks now, with forecasts generally tending to weaken and fall apart as the event unfolds. Lets hope this one comes to fruition to deliver some chunky S-SE swell. 

In the short run todays long period S swell will come down a notch tomorrow but with 3ft sets remaining, bigger 4ft on the Hunter and prime S swell magnets. Clean-ish conditions early with NW winds before N’lies kick up to mod/fresh strength in the a’noon.

Similar winds for Wed, likely boosted a notch as the trough/front approaches. It’ll be a mop up day for S swell leftovers with 2-3ft sets at S facing beaches, easing through the day. NE windswell should see a few sidewinders to 2ft through the day but you’ll probably have to surf in the fetch to get the most size.

Thursday looks interesting. A trough approaches, along with a frontal system from the south. Depending on how the trough behaves we may see a period of light offshore flow before the trough deepens and moves offshore, bringing freshening S’lies. We’ll finesse timing on Wed. We’re likely to see a mixed bag in the water, with easing NE swell and some E/NE swell filtering down from the sub-tropics where there are broad E’ly infeeds located in the Northern Tasman and South Pacific. Not much size for the region but we should see some 2ft surf, so if winds behave expect some fun beachies for the morning. 

By Friday the trough is expected to deepen in the Tasman, anchored by an advancing high in the Bight. That should see fresh S’ly winds and a fetch extending proximate to the NSW Coast down past Tasmania. Under this scenario we’ll be expecting a steep building trend in new S swell through the day, provisionally up into the 4-5ft range during the a’noon. We’ll see how it looks on Wed for size and timing.

This weekend (Sep 2-3)

Plenty of mid period S swell for Sat, under current modelling, with size in the 4-5ft range likely. Winds should remain mod/fresh SSW-S through the morning but if the low pressure trough forms a broad surface low as expected and moves away to the East, we’ll see winds ease off through the day. That initial burst of S swell is likely to ease back with it.

Looks like easing swells for Sun, although models are divergent so we may see substantial revisions through the week. Winds should improve, tending light W to W/NW under a light troughy flow. We’ll pencil in 2-3ft of S swell easing through the day, with the proviso we may see an upgrade if the European model comes to fruition which suggests a reinforcement from the SSE-SE through the day.

Next week (Sep 4 onwards)

We’ll have to see what happens with the low pressure in the Tasman, but swell from this source should still have some legs into next week. GFS suggests a nice fetch out of Cook Strait forming on the weekend (see below) as the low drifts towards NZ, with some tasty swell from the SE-E/SE potentially in the 3-4ft range Tues into Wed.

Mon is likely to see small S-SSE swell depending on the evolution of the low. We’re also likely to see some E/NE swell from the infeed into the depression drifting down from the South Pacific. 

Winds look tricky under a troughy pattern, although N’lies are most likely Mon.

An advancing front will bring a wind change sometime Tues/Wed.

That front is tied to a complex low system passing under the continent into the lower Tasman mid next week. It’s likely to bring S swell pulses later next week, so check back in on Wed and we’ll see how they are shaping up for size and timing. 

Seeya then.