Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 18th July)

Forecast Summary (tl;dr)

• Small flush of S'ly swell late Mon, prob with an onshore change
• Solid S'ly swell Tues but with breezey southerlies, tending SE in the a’noon
• Better S/SE tending SE swell Wed/Thurs, but onshore SE-ESE winds a problem
• Onshore winds continue Fri and into the weekend with building short range ESE swell
• Stronger E/NE tending E swell filling in over the weekend as tropical low drifts down from the Coral Sea
• Looks like a few good/great days early/mid next week with plenty of E swell and offshore winds

Recap

Pleasant weekend of small surf just passed. Saturday saw a few 2ft sets across open stretches with bigger 3ft sets on the Hunter and light winds. Sunday saw smaller surf, topping out around 1-2ft across most of the region and the Hunter hanging in with bigger 2-3ft sets and NW winds. Tiny surf across most of the region today, less than a foot at most places with S swell magnets like the Hunter seeing the odd 2footer.

We’re looking at another dynamic week ahead, with swell from across the seaward facing compass rose. Read on for details.

Gentle and clean surf over the weekend

This week (July 18-22)

Surf comes from a wide variety of sources this week as a typical strong winter cold front gets shunted aside by a very La Niña looking synoptic pattern, more reminiscent of Feb/Mar than July. This will see a very strong southwards located high pressure system set up a strong ridge along most of the Eastern seaboard, acting as an anvil for a tropical low to push against later in the week. The low forms as an upper trough across inland QLD enters the Coral Sea on Thurs, with a surface trough in the Coral Sea deepening into a surface low forming gales adjacent to the CQ/Fraser Coast, before the system moves towards the North Island over the weekend.

In the short run we’ll be looking at deteriorating conditions through Tues as the strong ridge builds with a fresh S’ly flow, tending SE at similar strength through the a’noon. There’ll be plenty of strong, mid-period S swell on offer as the front pushes aggressively into the Tasman today, with size in the 3-4ft range early, reaching 5-6ft through the a’noon at S exposed breaks. Expect to sacrifice a lot of that size though, to get a surfable wave at the more sheltered spots. 

Winds deteriorate further Wed, with a mod/fresh SSE to SE flow expected. There may be just enough slack in the pressure gradient and microscale wind effects for a light land breeze north of the Harbour, but expect that S’ly flow to kick in early almost every where else.

Still lots of swell energy from the southern quadrant on offer Wed. Expect size in the 4-5ft range early with a late pulse of more SSE angled swell as a secondary low stalls near the South Island later Mon/Tues and aims up at the NSW Coast (see below). Winds will be very unfavourable but if you can find a sheltered spot there should be enough swell energy on tap to refract into it at a reduced size.

The latter part of the week sees the dominant high strengthen and be just east of Tasmania on Thurs morning, with a deepening trough of low pressure off the CQ/Fraser Coast. Between those two systems we’ll be expecting a ridge of high pressure and onshore SE/ESE winds across most of the East Coast. The map will look spectacular but the surf will be marred by the onshore flow, likely ESE and hard to find shelter from. Shame about the wind because strong leftover SSE swell will hold in the 4-5ft range through the morning before easing off to be mostly replaced by short range ESE from the ridge. Surface conditions are expected to be a mess though, so keep expectations pegged very low.

By the end of the working week and we’ll be seeing mostly short period local swell from the onshore winds in the Tasman a with a continuing onshore flow. No quality is expected, with a messy 3-4ft of windswell on offer, perhaps offering up some peaks for the very keen at more sheltered breaks, although the showery pattern will be a turn-off for most. It does offer up a slim chance of some lighter winds around rain bands and squalls.

This weekend (July 23-24)

No change to the onshore pattern is expected this weekend, so gird your loins. That SE-ESE wind looks to persist all weekend, perhaps easing down a notch or two Sunday and shifting more SE-SSE.

While the position of the low will generate the largest surf for the sub-tropics (probably too large!), the general wind field is broad enough and migrates far enough South to generate a significant E/NE to E swell for temperate NSW.

We’ll start to see that swell build Sat under current modelling. That should see size from the E/NE build from around 3-5ft early, up into the 4-6ft range by close of play. The more direct swell angle will favour more protected locations but winds will still be an issue for most of the region.

Swell muscles up further into Sunday and we should see solid 6ft surf from the E as the low tracks southwards. As it does, winds will shift more SE to SSE and that will open up a greater range of protected spots. Keep your eyes on local wind obs through Sunday.

Next week (July 25 onwards)

The tropical low looks to slowly drift towards the North Island later this weekend and into early next week, with a slow easing signal of E swell the likely result this far out.

Winds should improve, slowly on Mon, with a lighter SW-S flow on offer, and size in the 4-5ft range.

A weak front Tues sees a more true offshore flow, with the first clean day in a week. Looks good surf-wise too, with continuing E swell in the 4-5ft range.

This set-up of offshore winds and E swell in the well overhead range lasts into Wed, so pencil in some time next week once the onshore pattern relaxes and we get back to more traditional winter wind flows.

Longer term and looks like the E swell will slowly linger and ease through until later next week. A cold front suggests a pulse of S swell through the same period.

We just have to get through this onshore period first.

Check back Wed for a fresh update.