Sydney Hunter Illawarra Surf Forecast by Ben Matson (issued Fri 17th Feb)

Forecast Summary (tl;dr)

• Small average weekend of waves, nothing special
• Small long period S'ly swell Mon
• Better long period S'ly swell Tues, though expect large variations in size across the region
• E'ly swell sources later next week
• Tropics looking good long term

Recap

Easing 3-4ft surf from Cyclone Gabrielle on Thursday still provided great waves with early light winds, ahead of smaller surf and onshores into the afternoon. Similar winds played out today with smaller swells in the 2ft range including some minor SE energy.

This weekend (Feb 18-19)

The main synoptic feature for the weekend is a southerly change due into the Sydney region early Sunday morning.

Freshening NE winds on Saturday will deteriorate surface conditions, and with only small leftover surf from today there isn't much to get excited about. We'll see building NE windswells through the day but no major quality is expected. A small level of leftover SE swell is also likely.

Building north-east energy should reach 2-3ft very late in the afternoon, and we may see a similar size at first light Sunday at reliable NE swell magnets - but the approaching southerly change will disrupt the generation of NE windswell from about midnight, which suggests a downwards trend from perhaps 3am onwards.

As such, there's an even chance that the NE swell could be almost gone before the sun comes up. It'll certainly be on the fast slide downwards.

So, if aiming for the Sunday dawn patrol, make it snappy, and keep your expectations low. Beaches not open to the NE will be much smaller too.

Sunday's southerly winds look fresh early though there's a few caveats: (1) latest high res model data suggests the southerly may only just nose into the Cenny Coast, and perhaps not quite reach Newcastle ('tis a moot point though, as the NE swell will be largely shadowed across the Hunter anyway), (2) we'll see a small S'ly windswell build through the morning, and (3) local southerly winds will ease through the afternoon.

I really can't pick an ideal window of opportunity this weekend, it's certainly a little grim compared to the start of this week. But there will be waves if you're desperate.

Next week (Feb 20 onwards)

An interesting succession of poorly aligned but explosive Southern Ocean low pressure systems below the continent will generate a spread of acute south swell along the Southern NSW coast early next week.

The first swell doesn't look much chop, as it's tracking perpendicular through the swell window, and core wind speeds weren't terribly strong either. Glancing energy is expected at a handful of reliable south friendly beaches on Monday and I'll be surprised if there's much more than a foot or two on offer. We may see some minor NE windswell too.

The second long period south swell is expected Tuesday, and will have been generated by a far stronger system, displaying core winds of 50-60kts, south-west of Tasmania on Sunday (see below). Its alignment still isn't great and Tasmania will shadow the bulk energy, but it's a very powerful storm whose energy will probably get into unusual places more efficiently than normal.

Model guidance suggests the leading edge swell periods could top out north of 20 seconds (arriving in the early hours of Tuesday morning) though the bulk surfable energy will be some distance behind, pushing along the coast into the afternoon then easing into Wednesday.

It's a really tricky system to have confident in wave heights from as we'll see an enormous spread of wave heights from beach to beach, and also from coastal region to coastal region.

So, if it all comes together, reliable south swell magnets (I'm looking at you, Newcastle) could pick up 5--6ft sets though I suspect most south facing beaches will reach an inconsistent 3ft+ into Tuesday afternoon, and many locations will dip out completely (mainly those not directly open to the south). It's likely to be very hit and miss but should absolutely be on your radar for opportunities, given Monday's freshening NE flow will give way to a more variable pattern as a local trough sets up camp across the region.

Long term outlook suggests more activity form the eastern quadrant as a mid-week ridge builds through the Tasman Sea and the trades also muscle up across the Coral Sea and South Pacific. Nothing great is expected but it'll keep the open beaches workable.

Even further out into the following week, and it's looking like our eyes will be focused back to the north-east as monsoonal activity pushes across the top end and down from the tropics next weekend. Gut feel for the long term trend from that region is very good right now.  

Have a great weekend, see you Monday!