Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Wed 26th Mar)

Features of the Forecast (tl;dr)

• Small clean leftovers Thurs/Fri
• Mini black nor-easter event sees building NE swells Sat with fresh NE-E/NE winds
• Sun has potential to be very good with offshore winds and plenty of NE-E/NE swell
• E/NE swell persists into next week at a fun size with good winds likely 
• Still some sizey S swell a possibility depending on movement and position of low off the South Coast next week- check back Fri for latest updates

Recap

Long period S/SE groundswell exceeded wave model outputs but was in line with manual f/cast expectations from late last week and Mon. Sets were very inconsistent but S exposed breaks, particularly on the South Coast and Central/Hunter regions showed 3-4ft surf with occ. bigger 5ft sets. A good reef or very good sandbank was required to make surfable sense out of the very, long-lined swell with conditions being favourable under light winds. Size is now on the downwards trend with the occ. 3-4ft set still there for the patient with clean conditions under light offshore land breezes which will tend to light seabreezes through the day. 

Long lines of swell closed out most beachies

This week (Mar 26- 28)

A major tropical event is unfolding as an active phase of the MJO sparks a late season monsoonal surge. That is seeing a monsoon trough stretched across the continent with a TC in the Indian Ocean well offshore from the Pilbara, a monsoonal low inland of the NT/QLD border and monsoonal activity in the Coral Sea. It’s likely we will see remnants of the inland monsoon low approach the SEQLD/NSW Coast during the weekend, dragging a moist NE flow down from the tropics and creating a mini black nor-easter event. We’ll see surf from this NE-E/NE infeed propagate from the sub-tropics down to temperate regions over the weekend. Models are then mixed as to whether the southern edge of the trough exits the coast and forms a surface low, potentially with the return flow generating S swells into next week. Lots of action ahead with this  dynamic pattern so keep tabs because there will be revisions as we get closer to the event.

Not much in the short run to deal with. Light winds both days, tending E/SE through Thurs, more E then NE on Fri.

We’ll see a small blend of easing S/SE and S swells tomorrow which should offer a 2ft wave at S exposed breaks with a 3ft set possible at S swell magnets.

That will ease back even further Fri with surf under 2ft at magnets, tiny/flat elsewhere. 

This weekend (Mar 29 - 30)

We’ll see building NE-E/NE swells through Sat as the trough drags the strong infeed down the NSW Coast. With that will come an increase in onshore N/NE-NE tending NE-E/NE winds so the day may end up a write-off for most spots. Likely small to start (but with better conditions) in the 3ft range but through the a’noon we’ll see building, stormy swells pushing up into the 4-5ft range, perhaps a notch bigger depending on windspeeds in the fetch. 

If Sat is a write-off, Sun has the potential to be very good indeed. Under current modelling we should see the southern extent of the trough exit the South Coast (likely just south of Jervis Bay- see below) in the early hrs of Sun morning. This would drag an offshore outflow north of the trough which looks to form a small surface low. If this comes to pass, we’ll wake up Sun morning to offshore W-W/NW winds, which will likely tend W/SW-SW through the day, possibly tending to light NE breezes. We’ll fine-tune those winds on Fri. Surf from the NE-E/NE should be sizey- in the 6ft range  and fully pumping due to the proximity of the fetch. We may see an easing in the a’noon as the infeed fetch migrates away from the coast. 

Just a caveat, there’s still some uncertainty with respect to winds depending on where, or if, the trough exits the coast and forms a small low. Odds are firming though that we’ll see good/great surf through Sun for areas north of the trough.

Next week (Mar 31 onwards)

The NE-E/NE infeed remains slow moving into early next week- feeding into a N-S trough as it slowly moves east across the Tasman. That leads to moderate/high confidence we’ll see a couple of days of good quality E/NE swell through Mon and Tues- likely with offshore winds.

The potential for S swell still remains a bit more uncertain. 

ECMWF is more bullish with a tight, compact low sitting east of Tasmania and gales in the Southern swell window, although they will be much better aligned for southern NSW, with areas north of Seal Rocks shadowed by the Hunter Curve. It’s possible we could see a sharp rise in S swell Mon under this scenario, persisting into Tues before easing. 

GFS is less optimistic with the surface low weaker and remaining tight to the Gippsland Coast before retrograding back into Eastern Bass Strait and then towards Tasmania with no effective swell generating S quadrant winds in the swell window.

We’ll see how this shakes out over the next 36-48hrs and report back Fri.

Seeya then!