Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 18th September)

Best Days: Surfable most days, just wind affected later Sat and Sun, and maybe Mon. Plenty of surf around though.

Recap: Despite peak periods increasing to 17-18 seconds across some Southern NSW buoys on Thursday with fresh southerly swell energy, wave heights have fallen below expectations over the last few days, reaching 2-3ft across most south facing beaches and 3-4ft across the Hunter. Winds were light for most of Thursday ahead of a gusty afternoon southerly change, and today has seen easing light SW tending S’y winds south from Sydney, though still moderate to fresh S’ly across the Hunter, and with an additional short range S/SE swell on top. 

This weekend (Sep 19 - 20)

There’s no change to the weekend forecast. We’ve got developing north-east tending northerly winds across the coast and they’re going to create problems at a few beaches. But, we have some interesting swell on the way.

A broad polar low/front below the continent mid-week has generated a strong new southerly groundswell that will bend up and into the Southern NSW coast through Saturday morning, reaching a peak late afternoon or early Sunday morning (expect smaller waves early Saturday). 

Set waves should reach a very inconsistent 3-4ft at most south facing beaches, and there'll be extremely long breaks between waves. Elsewhere, this southerly swell will be much smaller however the Hunter - and other reliable south swell magnets - should see occasional sets bigger than 4ft (maybe 5-6ft if we're lucky). Though once again, this will only favour a small number of locations.

Early Saturday will see temporarily light winds ahead of the developing NE breeze, and this will cause issues at many open beaches throughout the day and into Sunday, by which time there’ll be a little more north in the direction. 

In addition to the building south swell, we’ll also see short range E’ly tending NE swells from the local fetch, which should push up into the 2ft, almost 2-3ft range by Sunday (smaller Saturday). A little more size is possible on the South Coast due to the longer fetch length. It's just a shame conditions won't be terribly inspiring. 

Next week (Sep 21 onwards)

A stationary Tasman high will maintain northerly winds off Southern NSW into Monday, easing here and tending NW into Tuesday as a trough pushes off the coast, but remaining active out of the north off Northern NSW for another day or so (see below). Strengths look good for this latter phase but the anti-clockwise rotation of the fetch alignment will result in easing wave heights.

Nevertheless, this pattern will keep Southern NSW flush with short range NE swell through the start of next week, holding 3ft at exposed beaches Monday but abating slowly through Tuesday and then more rapidly into Wednesday. 

Despite the lingering N’ly breeze on Monday, we are likely to see pockets of lighter winds, maybe even N/NW at times (especially south from Sydney). Don’t get your hopes up but keep your eyes open for windows of opportunity. 

The weekend’s south swell will also steadily ease through this time frame. Early Monday should see some leftover sets and the afternoon has another pulse of very small but long period energy (easing slowly through Tuesday), but the NE swell will be the dominant source throughout this time frame. I’ll be surprised if there’s much more than a stray 2ft set across south facing beaches, maybe 3ft across the Hunter (and extremely inconsistent).

Wednesday will then see small residual swells from all directions with moderate to fresh offshore winds out of the west. 

A cut-off low will migrate below Tasmania on Tuesday and enter the lower Tasman Sea on Wednesday. It doesn’t look like a fantastic system at this stage (not particularly strong, and not very well aligned either) but Thursday should pick up 3ft+ of S’ly swell (bigger in the Hunter), with clean conditions under a westerly breeze.

Wave heights will the ease through Friday as a powerful front pushes across the eastern states and into the Tasman Sea, bringing about a gusty change and a rapid increase in sizeable southerly swell for next weekend. More on this in Monday’s notes. 

Have a great weekend!