Average surf ahead for Southern NSW; best on Saturday

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Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Monday 20th March)

Best Days: Wed: chance for an early clean peaky wave though the swell will be easing quickly. Thurs/Fri: combo of south swells and not-too-strong S'ly winds should allow for a few options. Sat/Sun: light winds and a fun, slowly easing SE swell with mainly light winds. 

Recap: It hasn’t been a great run for Southern NSW, there’s been plenty of surf but quality hasn’t been high and winds have been onshore. Wave heights peaked around the 6ft mark on Saturday and Sunday, easing to 3-4ft today. There have been pockets of lighter winds here and there but on the whole it really hasn’t been very memorable.

This week (Mar 21st - 24th)

A broad inland trough across the eastern states is slowly shifting eastwards. It’s freshening NE winds about the Southern NSW coast but ultimately won’t generate much quality surf over the next few days, owing to a lack of strength in the surface wind field. 

This, combined with  a moderate ridge through the northern Tasman Sea (generating a spread of small trade for our region) should keep wave heights in around the 2-3ft on Tuesday and perhaps early Wednesday, before surf size eases steadily throughout Wednesday to 1-2ft. 

Winds will remain moderate N/NE on Tuesday but will shift NW on Wednesday as the trough moves off the South Coast, forming a small surface low in the central/southern Tasman Sea. This transition will clean up conditions however the surf isn’t expected to be very strong and with a rapid easing trend during the day it’s hard to have confidence whether Wednesday’s cleaner but smaller surf will be better than Tuesday’s bigger but bumpier offerings.

The developing Tasman Low will push a southerly change across the Far South Coast later Wednesday, reaching Sydney overnight though easing through Thursday as the low tracks to the E/SE. So we’ll be under a southerly influence on Thursday but I don’t think it’s going to cause too many problems. 

The low will also generate a new S/SE swell though a short fetch length will limit surf heights - a shame too, as the low will develop in a great part of our mid-range SE swell window, and will display good speeds of 30-35kts+ at its core. 

This new swell is expected to build through Thursday, reaching a peak across the Sydney coast in the afternoon (earlier down south) and holding into Friday morning before easing a little into Friday afternoon. South facing beaches should pick up occasional 3-4ft sets from this source, though it’ll be smaller elsewhere with just some minor residual trade swell around 1-2ft. Note, this is higher than what our automated model is estimating (3ft) and there's a chance for an upgrade if the low stalls and strengthens in the Tasman Sea.

Also in the water from late Thursday through Friday will be a small long period S’ly groundswell, generated by an intense polar low that tracked under Western Australia over the weekend. It was positioned an enormous distance from the Australian East Coast, and also tracked outside the periphery of our swell window, however we should see some influence from the latter stages of this low (beneath South Australia, today) as it skirts the ice shelf. 

At this stage I’d be surprised to see much more than extremely inconsistent 2-3ft sets from late Thursday (again, arriving earlier across the South Coast) through Friday - which is less size than what I’m expecting from the Tasman Low - so being very infrequent, they’ll be hard to discern beneath the mix. But it’s worth detailing this swell in the event that the models go haywire on the Tasman Low over the coming days (unlikely, but possible). 

Friday’s winds should remain light to moderate from the southern quadrant (early light SW tending S then S/SE during the day). So conditions won’t be great at south facing beaches but it’ll be workable.

This weekend (Mar 25th - 26th)

Looks like the Tasman Low will slowly weaken and swing clockwise, away from our swell window through Friday and into Saturday. This will lead to a slow decrease in SE swell over the weekend.

A redeveloping coastal trough across Southern NSW will maintain NE winds though no great strength is expected at this stage. So conditions should be OK both days, though there is a risk that we’ll see future model updates pick up the projected speeds. 

As for size, Saturday should hold somewhere around the 3-4ft mark at south facing beaches (smaller elsewhere), before easing during the day to 2-3ft by Sunday morning and then 1-2ft by Sunday afternoon. It doesn’t look perfect but to be honest I’d prefer these smaller, more placcid conditions to the large windy junk that was dished up last weekend.

Next week (Mar 27th onwards)

Nothing amazing standing out in next week’s forecast at this stage, just a strengthening NE winds through Monday and Tuesday and likely increase in short range NE windswell.