Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri 4th Feb)

Forecast Summary (tl;dr)

• Sustained period of large surf developing over the coming days, persisting through mid-next week
• Windy for the most part under gusty SE breezes
• Strong SE/ESE swell pulse Tues/Wed
• Chance for windows of cleaner options likely Wed as a low pushes close to the coast
• Stacks of swell for the long term too, stay tuned for updates

Recap

Building swells have been the order of the last 36-48hrs  as the Tasman Sea becomes inflamed with a long fetch of strong winds to gales, courtesy of a monster high and embedded lows, along the leading edge of the high. Thats’s seen surf push up from 3-4ft yesterday, bigger 4-5ft on the Hunter up into the 4-5ft range today, 5-6ft on the Hunter. Strong S’ly quarter winds are accompanying the swell, SW for a brief period North of the Harbour allowing some more open beaches to be surfed. For the most part, some protection from strong S’lies has dictated surf able locations and these more protected spots are running a bit smaller than more exposed stretches of coast.  This pattern of strong S’ly quarter winds is going to be with us for a while, so buckle up. Details below.

Plenty of swell already getting into more sheltered spots

This weekend (Feb 6 - 7)

Not much change to the weekend f/cast. The blocking pattern mentioned in Wed’s notes is now well set up, noteworthy for it’s length and duration. A monster high moving through the Bight is strengthening with the pressure gradient tightened along the entire ridge line by a low pressure trough with embedded low systems in it. The trough extends from the South Island New Zealand up to the monsoon trough across Cape York Peninsula and into the Gulf of Carpenteria. 

The whole blocking pattern is slow moving- the high is only just south of Tasmania by the end of the weekend- so the weekend wind forecast is essentially stable. Fresh S to SE winds both days. Mostly SE though, with less chance of a window of morning SW winds compared to the last couple of days.

Surf wise there’ll be plenty of swell both days. 

As mentioned Wed, a larger pulse Sat morning from an intensification of winds along the trough line will see surf boost up into the 6ft+  range. Expect the biggest surf in the north of the f/cast region and only a few select spots will be surf able under the prevailing wind regime. Expect smaller at more protected spots. There’ll be some longer period S swell trains in the water as well which will aid refraction into the more  sheltered spots.

No great change Sun, surf heights comes down a notch as the longer period pulse from Sat settles but given the prevailing wind and sea state it won’t make much a of material difference. We’ll still be looking at 5-6ft surf across most of the region, bigger in the north and with smaller surf at the more sheltered spots. 

Next week (Feb 8 onwards)

Whoa, it’s a dynamic brew shaping up next week. A strong monsoonal surge pushing off the tropics into the Coral Sea is super-charged by the vorticity created by the monster high pressure ridge. Models now seem in broad agreement that a large, dual-centred,  low pressure gyre forms across the Coral Sea/South Pacific and into the North Tasman Sea (see below). It looks more like a North Pacific “Hawaiian-style” system than a typical East Coast set-up.

The Tasman sea end of the gyre deepens and retrogrades later this weekend and into Monday. This aims  a fetch of SE-E/SE gales from Cook Strait into the Central Tasman, straight back at the Central NSW Coast. 

Monday will see a holdig of size in the 4-6ft range with winds just starting to tilt more S/SE , compared to the weekends SE winds. Same equation applies, you'll need to find some wind protection to find a clean or semi-clean wave.

Tuesday sees the stronger SE-E/SE swell from the aforementioned fetch make landfall. At this stage we’re looking at an increase in size likely after lunch into the 6-8ft range. With the retrograding low, winds will start to tilt more straight S’ly, perhaps even SSW, which should open up a few more locations. 

By mid next week winds should start to settle and become more favourable. The Tasman low will have pushed closer to the coast and dissipated, leaving a much weaker synoptic environment, with a good chance of lighter SW breezes inshore. Wed looks good for solid SE groundswell in the 6ft+ range and morning SW winds.

The end of next week will depend on developments from the South Pacific end of the large, low pressure gyre. There’s a bit of model variance still to work through, with GFS suggesting a larger system drifting down from near Fiji, developing a fetch of E winds off the top of the North Island before tracking through the Tasman. That suggests a pulse of E/NE to E’ly swell possibly arriving by Fri next week with the weekend seeing E swell.

EC has a more compact system which becomes absorbed into a mid-latitude system as a strong new high pressure ridge builds. That indicates a pulse of E/NE swell in a similar timeframe before another round of building SE wind and swell into next weekend.

There’s plenty to occupy us in the short term so check back Mon and we’ll run a fresh ruler over it then.

Till then, have a great weekend!