Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 28th Mar)

Forecast Summary (tl;dr)

• Fun waves Tues AM, with flukey winds around trough line, best on the Hunter
• Increasing S to SE winds Wed, with kick in E/NE swell through the PM
• Major increase in S/SE swell likely Thurs as strong front and surface low combine in Tasman, with gale force S'lies developing
• XL S swell Fri/Sat as storm force low sits off coast. Huge seas and gale force S'lies confine surf to only a few spots
• Slow easing in swell Sun and into Mon (still massive!), with fresh S'ly winds
• Slow roll-off in size continues into mid next week with S to SE winds
• Checking the tropics later next week for depression or cyclone, stay tuned for updates

Recap

A few options over the weekend with mostly small and onshore surf Sat in the 2ft range. Winds were lighter and more variable Sunday and a pulse of S swell provided some inconsistent 3ft+ waves at S facing beaches during the day. The week has started well with a combo of S’ly groundswell and shorter range E/NE swell providing some juicy A frame beach breaks in the 3-4ft range with a variable/offshore flow around a coastal trough line. 

A very dynamic week ahead as a trough and cold front interact with a strong Tasman low expected to form mid-week and generate an XL (persistent) swell. Read on for details.

Combination swell produces very shapely peaks, with light winds

This week (Mar 28-Apr1)

OK, it’s going to be a wild week so lets look at the moving parts and sketch out the order of events, whilst acknowledging that it will be a highly dynamic outlook requiring fine tuning as the troughs, front, upper trough and expected eventual storm force surface low all interact.

A coastal trough lies along most of the NSW  Coast, with a pronounced deepening off the North Coast. A parallel Monsoon Trough extends down the Coral Sea and out to New Caledonia. High pressure over New Zealand is feeding very moist E’ly winds into these trough systems. The northern end of the coastal trough system is expected to deepen into a surface low through tonight into tomorrow, off the SEQLD coast, moving south through Wednesday.

Overnight Wed into Thursday the surface low is expected to interact with a cold front to form a major, winter-calibre Tasman low generating strong to gale force winds and building a large to XL surf from the SE late this week into the weekend.

In the short run and the part of the trough lying just offshore from Sydney deepens a little tomorrow. There’ll still be a convergence zone likely just north of the Central Coast, with NW to N winds from there up to the Hunter, tending light NE during the day.

South of the trough line, from the South Coast/Illawarra and up to Sydney we’ll expect SW winds early tending S to SE and freshening during the day. 

Surf-wise size is expected to be down a notch on todays 3-4ft- so 3ft at most spots, out of the E/NE so there should be an even spread of surf across most of the region. 

By Wed the surface low is expected to be off the Coffs Coast and still moving south. A cold front is expected to tip the edge of Tasmania and enter the Tasman Sea. Early winds will be light, before they begin to freshen from the S, as the front and low begin to interact. There’ll be 2-3ft of E/NE swell on offer, if you can get in during the morning session before the wind hits. It’s likely we’ll see a late increase in E/NE swell from the winds infeeding into the surface low, as well as some short range S swell. If you see something surfable Wednesday, then grab it.

Because things escalate very quickly on Thursday. The front and the deepening low sees a thin fetch of strong to gale force SSW to S winds develop along the Central NSW Coastline. By lunch-time the low will be winding up rapidly- possibly bombing- with severe gales to storm force winds developing off the NSW Coast and extending down through the lower Tasman. That will see a rapid rise in S swell, likely building from 4-6ft early, up into the 8-10ft range, bigger 10ft+ at S facing beaches. Only the most protected spots and novelty locations will be surfable by this stage.

By Fri April 1st, the surf is expected to be huge, as a storm force low sits almost due East of Sydney (see below). How big? 12-15ft across open stretches is on the cards, bigger at exposed S facing coastlines. Gale force SSW to S’ly winds will again confine surf to the most protected locations. 

Probably a better day to hunker down than chase surf, unless you have a novelty spot in mind or are confident in huge surf at the very few spots handling the size.

This weekend (Apr 2-3)

Massive surf extends over the weekend, under current modelling. Both major models show the low only slow moving off the coast, almost due East of Sydney.

That will see strong to gale force SSW to S winds continuing Sat, possibly easing a notch Sunday.

Expect size to hold in the 12-15ft range Sat, bigger at exposed S facing coasts, easing back a few notches Sun as the low contracts and fills in a little. 

It’ll still be in the 10ft+ range Sun, bigger at S facing coasts. 

Same caveats apply, only a few spots working and even fewer handling the size and wind. 

Not a weekend for anyone who isn’t ultra experienced and confident/prepared for big surf. 

Next week (Apr4 onwards)

The Tasman low is expected to drift away to the NE early next week, with swell easing- but only slowly- as it does so.

Unfortunately, it doesn’t look like we’ll get a super clean day as the swell drops, due to a monster high moving in from the Bight. This quickly sets up a ridge along the NSW Coast, with S to SE winds becoming established.

Monday will still be very rowdy with large surf from the S-S/SE, likely still in the 6-8ft range and fresh S’ly winds. Size should ease through the day but winds will remain fresh so finding a wave will involve getting protection from the winds. Expect smaller, but more manageable surf in more protected Bays.

Surf will slowly ease back through to the middle of next week. There’s going to be an insane amount of energy in the Tasman Sea so we’ll expect a slow roll-off in size. Winds will remain a problem though with the high pressure ridge maintaining a S to SE flow at least into the middle of next week.

Longer term and we’ll be monitoring the tropical Coral Sea with models now hinting through successive model runs of a tropical depression, possible cyclone, in the Coral Sea. This far out, track and ultimate surf potential are purely speculative, but we’ll keep tabs on that while we monitor the much more pressing developments in the Tasman Sea this week.

Chexl back Wed for a fresh update.