Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 23rd September)

Best Days: Sat/Sun: easing S'ly swell with a reinforcing E/SE swell, plus good winds in general. Mon: fresh S'ly swell with mainly good winds. Tues PM/Wed: small E/SE swell.  

Recap: Thursday saw small residual S’ly swell across the coast with clean conditions under an offshore breeze. Today, a strong short range south swell has filled into the coast generated by a new low that formed off the South Coast overnight. South facing beaches are seeing solid 6ft sets though conditions are marred by gusty S/SW winds. Some locations saw a brief period of W/SW winds early morning.

This weekend (Saturday 24th - Sunday 25th)

We’ve got a great weekend of waves ahead. 

Today’s large southerly swell will ease rapidly overnight; the fetch is just starting to weaken within our swell window and this will soon cease to generate any new energy inside our immediate swell window. So, a downwards trend will result through the day though early morning should still see 3-5ft sets across south facing beaches (maybe a few bigger bombs across the Hunter).

However, this easing trend will be slightly arrested by a secondary E/SE swell, which is expected to fill in throughout the day - originating from a modest but broad E’ly fetch about the southern flank of the Tasman Low. This should contribute 3ft sets across most open beaches, which is about the likely overall size throughout the afternoon from both sources. 

Surface conditions look pretty good on Saturday, with no major synoptic flow so probably early light W’ly winds and afternoon sea breezes. Exposed stretches may see some leftover lumpiness from today’s gusty conditions but it’ll be on the improve throughout the day.

Surf size will ease further into Sunday, more quickly from the south than the east-southeast. This means we should see a relatively uniform size distribution across the coast though the trend will certainly be downwards. Early morning may see a few stray 2-3ft sets at exposed beaches but by the afternoon we could be back to the 1-2ft range - albeit peaky and quite surfable. 

Winds look pretty good on Sunday, mainly light to moderate W’ly breezes across most regions, with a mid-late afternoon S/SW change across the Far South Coast that probably won’t reach Sydney until well after after dinnertime. Either way, the morning should have the most size and best conditions.

Next week (Monday 26th onwards)

First up: today’s Tasman Low is expected to track slowly across New Zealand longitudes over the coming days, and will probably leave a trailing E’ly fetch existing western Cook Strait (the body of water separating New Zealand’s North and South Islands) over the weekend. The fetch doesn’t look very large but wind speeds are expected to become quite strong so we could see a small E’ly swell mid-week from this source (later Tues/Wed) in the 2ft range. 

Otherwise, Sunday’s overnight S’ly change will depart quickly to the east on Monday morning, probably leaving us in an early light offshore pattern though we can’t rule out a leftover southerly flow in some regions (probably the Hunter Coast).

The fetch tracking up along the South Coast in the lee of the change looks reasonable; 3ft+ sets are quite likely across south facing beaches (bigger in the Hunter) though it’ll be smaller elsewhere. There is also potential for a minor upgrade in projected surf size from this fetch; I’ll update in the comments below over the weekend. Thought I doubt we'll see much more than 4ft across exposed Sydney beaches from this source. 

This swell will ease quickly into Tuesday with winds remaining light offshore.

Looking further ahead, and a late S’ly change on Tuesday may generate a small south swell for Wednesday but nothing of any substance is expected.

The long range outlook for the end of the week and next weekend has a powerful front and low approaching Vic/SA later Wednesday and into Thursday.

Strengthening northerly winds overnight Wednesday and into Thursday may generate some short range NE swell for our region (on Thursday), but of much more interest is how this broader system will evolve as it tracks across south-eastern Australia. The latest model guidance suggests the parent low will probably reach maturity west of the Tasmanian divide, which means reduced swell prospects in our swell window - but we can’t rule out a reintensification once it tracks into the Tasman Sea either. 

It’s certainly a weather system to watch closely in the updated model runs because either way it’s going to  create a period of very windy conditions for the SE corner of the country. Let’s just hope those gales are aimed favourably within our swell window. 

Have a great weekend, see you Monday!