Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 4th Apr)

Forecast Summary (tl;dr)

• Small and clean Mon, slight uptick in S swell Tues
• Possible S swell Wed, with  onshore winds developing
• S/SE swell in the mix along with onshore winds Fri/Sat
• Short range E/SE swell likely to build in later Wed with onshore winds and extend through the week and into the weekend
• Longer period E swell from more tropical sources builds in Sat and extends into Tues/Wed next week with lighter winds
• Possibly another round of E to SE swell next week, stay tuned for updates

Recap

Wild weekend of surf as a storm force Tasman low generated some huge waves for Saturday. Surf at exposed S facing breaks was reported in the 15+ range through Sat morning, settling as the day went on. Some of the more notorious Sydney Big Wave spots were roaring at full throttle through the day which provided an amazing spectacle and some truly terrifying tubes for the big wavers out there. Early SW winds began to back off and tend more W’ly through the day as the low tracked southwards. Sunday started off with clean 4-6ft surf, with size ramping down quite quickly through the day to end up an inconsistent 2-3ft at close of play, with the odd 4footer on the Hunter. Surf has eased right back today with a few small 2ft leftovers on offer and light offshore tending variable winds. Lots of swell ahead this week, but unfortunately lots of onshore wind too. Read on for details. 

Very large swell on Saturday

This week (Apr 4-8)

A weak troughy pattern lies over most of the East Coast at the moment, with the remnants of the deep Tasman low meandering off the Gippsland Coast. This weak pattern persists until Wed, when a formidable blocking pattern consisting of a large peanut-shaped high pressure system sets up a strong ridge along the entire East Coast. That will direct a deep E’ly flow onto the coast throughout the f/cast region. A depression just to the North-West of New Caledonia now has a high chance of forming a tropical cyclone but this system is not expected to generate swell for Southern NSW under current modelling. A large cradling fetch of E to SE winds is better aimed at sub-tropical areas but should still produce some swell for the region later in the week. The proximate E’ly winds will be the main swell source for the region this week. 

In the short run and tomorrow will be the last day of light winds and nice conditions so make the most of it. Not much surf to speak of, just a tiny signal, in the 1ft range early. There may be a slight uptick in S swell later on generated by SW winds off the Gippsland Coast, but not exceeding 1-2ft at S facing beaches. Offshore winds early, will clock around E/SE to E/NE through the a’noon.

Onshore winds start to ramp up Wed, setting the tone for the rest of the week. Expect light winds early, with a small troughy area off Sydney leaving an area of weak pressure gradients. Surf will remain small though, just a foot or two at S facing beaches. Through the day winds will start to freshen from the E, but not exceeding 15 knots. A pulse of longer period S swell generated by a compact low passing through the lower Tasman Mon/Tues will see some 2-3ft sets at S facing beaches, but quality will be impaired by the onshore wind flow. 

E’ly winds ramp up further on Thurs as the high moves in with a cell either side of Tasmania. The strongest E’ly winds will be from the Mid North Coast down to Jervis Bay, with slightly lighter winds further south. Those E’lies will be feeding into an inland trough line, so along with the wind expect some pretty wet weather. A blend of S swell and developing short range E swell will see surf in the 2-3ft range early and the short range E swell will quickly become dominant and continue to build through the day, up into the 4-5ft range. It won’t be pretty with straight onshore E’ly to ENE’ly winds in excess of 20 knots expected.

Onshore winds continue through Friday, at similar strengths. That's the headline feature. There’ll be plenty of swell to play with. Strong, local E swell in the 5-6ft range, easing a notch during the day. S to S/SE swell generated by an intensification and stalling of the low that tracked through the Tasman early in the week will supply 3-4ft of surf into the mix. Hard to see any quality in amongst the onshore flow- although sheltered spots and reefs that can organise the chaotic elements into more shape will fare best if you can tolerate the chop and bump. Just don’t expect any smooth faces this week once that onshore flow kicks in. 

This weekend (Apr 9-10)

The high will be tracking E across the Tasman Sea later this week and into the weekend but the synoptic wind remains entrenched through Saturday, with E to E/NE winds. At least these winds should be starting to back down a few notches so waves will be onshore but not totally torn to bits. A mix of short range E and SSE swell trains will be overlapped by some thicker E swell generated by a large fetch in the Northern Tasman and Coral Seas which is anchoring the expected TC (Fili). That should see surf in the 3-5ft range, thicken up during the day, into the 4-5ft range. If you can handle the onshore winds there’ll be plenty of waves Sat. It's a classic "Summer" looking synoptic patterm and indicative of the La Nina pattern hanging on. (see below)

Winds finally back down Sun, as the high drifts far enough E to leave a light N’ly flow along the f/cast region. Expect a light NW flow early, tending to light N to NE breezes later in the day.

Solid mid period E swell in the 4-6ft range should see plenty of good to great options for Sunday. 

Next week (Apr11 onwards)

Plenty of action from the E to start of next week. Models show the cyclone or ex cyclone slow moving to the SE over the weekend before a turn to the S, with a large fetch of E to ESE’ly winds anchoring the system. That maintains plenty of E swell for the entire East Coast into next week. 

Winds will be the main factor but at this stage Mon looks great with a light NW to N flow. Coupled with 4-6ft of E swell there should be heaps of good options.

A small trough complicates things Tues but winds should be light, possibly tending S’ly during the day. E swell continues in the 3-5ft range, although this size will likely be finessed as we get closer to the date depending on the track of the cyclone. 

Plenty of E swell is expected to hang on into Wed, although I think wave models might be overcooking it a notch or two, we should still see at least 3-4ft of surf through the day. Winds are likely to freshen from the S as a trough deepens off the NSW Coast, likely the Mid North Coast.

Longer term and with high pressure continuing to move at Summer latitudes, and the trough off the coast, we may well see a rinse and repeat cycle of E to E/SE swell and a few days of onshore winds next week. The long lead time suggests substantial revision, but the La Niña style pattern seems to show no signs of letting up.

Check back Wed for the next update.