Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Wednesday 9th April)

Best Days: Thurs: nice conditions, easing inconsistent S'ly swell. Fri onwards: plenty of large S'ly swell though accompanied by gusty S'ly winds. 

Recap: How do you rate the accuracy of a forecast where some beaches are flat and others are solid? We’re in the midst of a long spell of flukey southerly swell that’s lighting up some beaches, but not even giving others the courtesy of a small rideable peak - even some beaches that usually pull in south swell pretty well. Yesterday saw occasional 2-3ft sets at some beaches (but flat at others), and today we’ve heard reports from the South Coast to the Hunter of 4ft+ bombs. Buoy data supports these observations with swell periods increasing to 15 seconds yesterday (with the first flukey south swell) and today’s second flukey south swell went up another notch to 17 seconds. Out of interest, this south swell is sourced from the same system generating the energy enroute to Tahiti, as per Craig’s article yesterday.

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This week (May 10 - 11)

Today’s long period southerly swell will peak overnight and ease slowly throughout Thursday. Again, there’ll be large range in size between exposed south facing beaches and other spots, and set waves will be inconsistent. 

At this stage it’s likely we’ll see many south facing beaches around the 2-3ft range early morning (easing to 1-2ft during the day, probably early on) though reliable swell magnets such as the Hunter coast may see early 3-4ft+ bombs before it trends down to 2-3ft by lunchtime. Winds will be freshening offshore all day so conditions will be clean. Expect long breaks between sets, and beaches that are not exposed to the south will be considerably smaller - almost flat in places.

A small trough-cum-closed low in the Central Tasman Sea also looks impressive in single synoptic snapshots but unfortunately it’s expected to be whisked away to the east more quickly than is desired for optimal swell generation. I’m doubtful on its swell potential (which is a shame as it’s very well aligned within our E/NE swell window) so I’m keeping my expectations low.

However, there’s a modest fetch trailing to the NE that should supply some slow, inconsistent 1-2ft waves building Thursday and holding into Friday but I’m just not confident that we’ll see much more size than that. The strength of the head of the fetch suggests more, but its forward track rapidly erodes that potential.

Also in the water on Friday is a possible small south swell originating from SW gales exiting eastern Bass Strait late Thursday. It’s not a particularly strong, sustained fetch so I’m doubtful of much size but occasional 2ft sets are possible throughout the day, more likely the afternoon.

As it is, Friday looks tricky on the surface anyway with gusty offshore winds at time. It’ll be very clean but small swells like this often struggle with gale force westerlies.

This weekend (May 12 - 13)

There's been a big swing in the model guidance for the weekend. In short, it’s sped up the timeline for this evolving cut off low across the Tasmanian/Victorian regions, that’ll transition into a Tasman Low as the weekend plays out.

And, it’s no less tricky to forecast for either. The latest model guidance has the low east of Bass Strait on Friday (see chart at end of this report), aiming a storm-force S/SE fetch into the Gippsland (eastern Victoria) as well as the southern and eastern Tasmanian coasts.  

This is just outside of our swell window, but we’re now expecting storm force southerly winds to develop parallel to the Southern NSW coast early Saturday morning. This will result in blustery westerlies tending south-west (by early/mid morning), then south-southwest throughout the day, along with a rapid increase in very large short range south swell. Our surf model is currently estimating 15ft (!) at south facing beaches late Saturday and Sunday, which is plausible given the local winds - though conditions will be victory-at-sea. In reality we’re probably looking at 10-12ft storm surf at the height of the event. Protected locations will be considerably smaller. 

Sunday looks much the same with easing through initially gale force plus SW winds and slowly abating (!) surf, likely in the 10-12ft range and becoming smaller throughout the day. Therefore, protected southern corners will have the only rideable options this weekend. Even then it’s going to be hard work.

Let’s fine tune the specifics on Friday. It’s possible we could see a downgrade in the size but any surf we see this weekend is highly likely to be accompanied with very windy conditions. And that ain’t a good thing in my books.

Next week (May 14 onwards)

This Tasman Low will remain slow moving for a few days into next week, in fact there’s a suggestion we’ll see an unrelated Southern Ocean front barrel through the lower Tasman Sea around Wednesday, giving it a second wind (boom, tish) and maintaining elevated wave heights across Southern NSW through the rest of the week. 

Therefore, most of next week looks sizeable and generally breezey. If anything, we’ll probably see a period between systems of lighter winds (say, later Monday or Tuesday?) but in general it’s looking like being an extended run of strong surf best suited to protected points, corners and coves. 

See you Friday!