Complex weekend of building E/NE swell; no shortage of waves next week either

Ben Matson picture
Ben Matson (thermalben)

Sydney, Hunter and Illawarra Surf Forecast by Ben Matson (issued Friday 1st May April)

Best Days: Sat: building E/NE swell but local winds will (again) likely create problems. Keep your expectations low. Sun: Strong E/NE swell and improving conditions as winds freshen from the S/SW (maybe early W/SW in a few areas). Mon/Tues: easing E/NE swell with generally good winds. Wed: strong new S'ly swell. Next Fri/Sat: another strong E/NE groundswell, and a new S'ly swell too.

Recap: Small south swell yesterday and today but with generally average conditions. Nothing to get interested in, that’s for sure.

This weekend (May 2 - 3)

The weekend outlook has been tricky all week, and even at less than a day out it’s still very complex. 

On the synoptic chart, we’ve got a deepening trough along the NSW Coast and an ECL has formed north of the Sunshine Coast. Gale force E/NE winds on the southern flank of the low - currently aimed into SE Qld and Far Northern NSW - are generating very large seas, however a broadening E/NE fetch covers a significant percentage of the Tasman Sea, stretching out northeast into the South Pacific. It’s a very impressive setup.  

Southern NSW won’t be directly influenced by the East Coast Low, as it’s expected to peak in intensity near the Far North Coast into Saturday, before weakening as it slides southwards (probably over land). Meanwhile, the elongated NSW trough will also slowly dissipate and move eastwards over the weekend, and the associated E/NE fetch will ease in strength.

But, we’re getting ahead of ourselves. Right now the fetch is strengthening in our swell window and we’re looking at building surf all day Saturday, ahead of a peak on Sunday morning.

Saturday’s waves will however be marred by mainly onshore winds. It’s hard to get a bearing how much strength we’ll see, as the models maintain the strongest winds well offshore - but it’s likely that their adverse effects will hold into the coastal margin, even if winds are only light to moderate at the beach. 

To that end, keep your expectations low for Saturday - I’m expecting bumpy surf building to 4-5ft throughout the day (smaller earlier). The only chance for something worthwhile is if we see a small embedded low form within the trough at the coast, prematurely swinging winds to the south (thereby opening up southern corners). In actual fact, this may have happened this afternoon across the Hunter (winds were S/SW at Nobbys, S’ly at Norah Head, and S/SE at North Head and Little Bay for a few hours).

Nevertheless, the broader coastal trough will move eastwards into Sunday, allowing a shallow change to push up the southern NSW coast during the morning, freshening S/SW winds about most areas (we should see early W/SW winds in a few areas, such as the Northern Beaches). Wave heights should holding the 4-6ft range, with slightly smaller surf in the Northern Hunter (owing to the shadowing effects of Seal Rocks) but bigger waves above 6ft are certainly possible south of Sydney. Expect a slight easing trend into the afternoon.

Next week (May 4 - 8)

We’ve got a lot of surf on tap for next week. The E/NE fetch stretching back into the South Pacific will remain active through the weekend, in fact the trade below south of Fiji/New Caledonia is expected to restrengthen around Tuesday, which will deliver an excellent pulse of E/NE groundswell for the end of the week. 

Prior to that, we’re looking at moderate E/NE swell easing to 3-5ft on Monday and further to 2-3ft on Tuesday and Wednesday. Light variable winds are expected on Monday ahead of pre-frontal freshening NW winds on Tuesday as a vigorous front approaches from the west.

This front and a deep low pressure system will exist eastern Bass Strait on Tuesday,  and although poorly aligned within our swell window, storm force westerly winds should generate a strong pulse of S’ly swell for Wednesday - between 3ft and maybe 5ft at south facing beaches (bigger 4-6ft sets in the Hunter). Winds should be moderate W/SW tending SW across the coast in the wake of an overnight S’ly change, so mixed in with the easing E/NE swell there should be some good options across the coast.

A series of powerful - and much broader - Southern Ocean fronts trailing behind will then set up an extended period of solid south swell for late Friday and the weekend (3-5ft south facing beaches), but before they arrive we’ll see a strong E/NE groundswell push through, originating from the aforementioned intensification within the trades (up near New Cal) on Tuesday (see chart below).

At this stage the leading edge is expected to arrive late Thursday - probably overnight - so Friday is where we’ll see most of this swell fill in, and exposed NE facing coasts should pull in anywhere between 3ft and possibly even 5ft of quality groundswell. 

Ordinarily, swells originating from this kind of fetch in this part of our swell window would probably result in smaller surf, but as these developments will be occurring on a very active sea state (plus the added bonus of a slight fetch retrograde), this means that we’re likely to see slightly larger, stronger surf from this source. And the good news is that this swell window will remain active up until Thursday so we should see strong but easing E/NE swell through next weekend, possibly even some residual energy into the following Monday. 

So a solid south swell AND a solid E/NE swell arriving around the same time? Sounds ideal for a great round of beachbreak sessions. I’ll update this outlook with the availability of the latest weather data on Monday afternoon. ‘Till then, have a  great weekend!


blindboy's picture
blindboy's picture
blindboy Saturday, 2 May 2015 at 6:56pm

The water on the northern beaches is about as dirty as I have seen it since the North Head outfall was moved offshore. All the lagoons pouring out as well as the stormwater drains. Take care people there are some nasty pathogens lurking in the murk!

JackGregory's picture
JackGregory's picture
JackGregory Sunday, 3 May 2015 at 10:12am

Couple at Southern corners and a few clean up sets on the reef