Tricky long period swell for a couple of days, more south swell next week
Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 2nd December)
Best Days: Still potential for interesting long period (maybe sizeable) south swells on Thurs/Fri. A mix of small surf over the weekend, then a renewal of solid south swell from next Wed thru' the weekend.
Recap: Easing S’ly swells maintained 2-3ft sets early Tuesday before size eased into the afternoon. Freshening NE winds built a local windswell into the afternoon that held into this morning around 2-3ft, though fresh and gusty southerly winds have confirmed the only workable options to protected southern ends. Winds have eased this afternoon and gone SE, even E/SE in a few spots though it is still little gusty at times. Southerly swells are now building in behind the change, with size around 2-3ft at south facing beaches.
This week (Dec 3 - 4)
There are two sources to this afternoon’s southerly swell increase - a short fetch trailing the change, and also W/SW gales exiting eastern Bass Strait.
The former will dissipate rapidly overnight, whilst the latter will take a little longer to ease through Thursday morning - so maybe some 2-3ft leftovers early - but the main item on the short term agenda is a series of new long period south swells from an incredible low that formed south-west of Tasmania yesterday.
The image below shows storm force winds around the low, and also highlights the main headache I have at the moment - working out how much of this fetch is shadowed behind Tasmania, and how much sits just inside the western periphery of our acute south swell window.
Make no mistake - had this low been positioned another 5-10 degree further east (and, a little more meridional in alignment), then we’d have been looking at easy 15ft+ surf across south facing beaches. It’s a beast of a system.
But, the primary fetch is slightly off axis, and Tasmania will absorb a lot of the energy, so we can expect a much smaller percentage of long period energy to bend up along the NSW coast into Thursday. The models certainly don’t like this swell either, expecting just 0.3m at 17 seconds early Thursday morning (Northern Beaches). But I think this is a major under call.
Enough waffling. How big? Some south swell magnets could easily pick up 5-6ft+ sets. But, I expect they’ll be the exception rather than the rule, so if you’re hunting these kinds of waves then the usual suspects (i.e. Hunter region, reliable offshore bombies) will be your best bet.
Most south facing beaches will probably max out in the 2-3ft+ range and it’ll be smaller at beaches not open to the south. This is not a high confidence event though, and the large periods (19-20 seconds) will create a much broader range in wave heights from beach to beach than usual south swells.
Conditions will be rapidly improving early with light winds, ahead of freshening afternoon NE breezes.
Friday looks nice and clean with light variable winds, and a slightly broader coverage of more useful southerly groundswell, from the main fetch as it traveled from underneath the Tasmania swell shadow today. It’s still a relatively low confidence event, but I can’t see any reason to downgrade Monday’s estimate of 3-4ft sets at south facing beaches (smaller elsewhere) reaching 4-6ft across reliable south swell magnets like the Hunter. Elsewhere we'll see smaller surf thanks to the swell direction.
This weekend (Dec 5 - 6)
A modest front under Tasmania on Friday should set up a small southerly swell for both days of the weekend, in addition to a smaller, more distant S/SE swell from the tail end of the primary low generating our Thurs/Fri fetch.
Model guidance suggests a low point early Saturday (before kicking in again into the afternoon and Sunday), though we’ll be coming off the Friday peak so at this stage I’ll probably just maintain inconsistent 2-3ft sets for south facing beaches all weekend, and recalibrate on Friday once we’ve been able to assess the performance of the two impending long period events Thurs/Fri (if it’s undersized Fri, then I’ll knock down Sat AM’s size a little).
Saturday morning should be clean with light winds ahead of strengthening NE breezes in the afternoon, as a strong front approaches from the west. As detailed in Monday’s notes, local winds look good for swell generation but the sequence is pretty quick and I’m concerned that we’ll see only a short lived pulse of NE swell, that might exclusively favour the overnight period.
So, there’s a chance for early 2ft+ sets Sunday morning, clean with offshore winds, though it'll be easing steadily through the day. We may also see a small S’ly swell into the afternoon, originating from W/SW gales exiting eastern Bass Strait. Surf conditions will remain clean with offshore winds all day.
Next week (Dec 7 onwards)
We’re still looking at elevated southerly swells through much of next week as the LWT stalls across our region and a deep Southern Ocean low slingshots secondary fronts through our south swell window. At this stage the pattern has been delayed a little - so I’m not confident on size for Monday - but Wednesday through the weekend is looking like seeing an extended period of sizeable, chunky surf.
See you Friday!