Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 6th March)

Forecast Summary (tl;dr)

• Small mixed bag continues this week with NE winds, NE windswell Mon PM/Tues
• Complex low moves into Tasman this week weakening as it does so, pulses of small S swell ahead from Wed-Fri
• Small S swell Sat, with potential for NE windswell in the PM
• S’ly change likely Sun with small leftovers from S and NE
• More small NE windswell next week as high pressure belt sits at more N’ly latitude

Recap

Fun options over the weekend with majority S swell and some supporting swell trains from the E supplying fun waves. Sat saw size in the 2-3ft range with light winds early tending E-SE in the a’noon. Sunday perked up in size as a last pulse of longer period S swell provided bigger 3-4ft sets at S facing beaches, 4-6ft at some magnets on the Central Coast. Conditions were clean early with NW winds before they clocked around NE and freshened in the a’noon, whipping up a small NE windswell. This morning has seen light N’ly biased breezes with a mixed bag of easing S swell, small E/NE swell and small E’ly swell- topping out at around 3ft at open beaches (it as since kicked with a few 4-5ft sets now in the mix). A strange pattern unfolds this week, details below. 

Cleanish options on the beaches as long period S swell fades out

This week (Mar6-10)

The synoptic set-up is split into two opposing camps at present with an active monsoon trough and monsoonal low in the Gulf of Carpentaria linked to an inland trough which is drawing down hot air from the Pilbara into NSW. Opposed to the strong tropical signal we have a large complex low pressure gyre approaching from the Southern Ocean, with a cold signal expected to just spread into temperate NSW. Unfortunately this strong cold outbreak now looks to stall just too far West (behind the swell shadow of Tasmania) to really deliver any strong S swell to the East Coast, before weakening as it moves into the Tasman Sea swell window proper. 

In the short run and todays hot N’lies and proximate NNE fetch whip up a useful NE windswell which is expected to peak through Tues morning in the 3ft+ range, perfectly timed for a clearing NW-W change as a trough moves offshore. Get in early as size will ease rapidly through the a’noon as he fetch gets shunted eastwards. A light a’noon seabreeze is on the cards. 

W’ly winds then kick in Wed as a front pushes through Bass Strait and temperate NSW becomes subject to the synoptic winds from the complex low. Not much surf expected Wed with small NE leftovers in the 1-2ft range, clean under offshore winds. Remnants off the coastal trough linger, causing a weak onshore flow in the a’noon. We may see a small, late kick in S swell from the Bass Strait fetch but Thurs is a better bet. Any increase is likely to be marginal.

A weak high pushing through the Bight at a more Northerly latitude combines with the slow moving low to drive a WSW-SW flow across temperate NSW Thurs, with winds tending SE in the a’noon as a weak ridge establishes. No great size is expected as small, directional S swell fills in. Sets to 2ft at S facing beaches can be expected.

The working week finishes with more small S swell - topping out at around 2ft at S facing beaches under current modelling. We can’t rule out a bit more S swell if the low under Aus moves E a little and brings swell generating fetches more directly into the swell window. But for now, the outlook is for small S swell with light winds as a high cell slips out over the region.

This weekend (Mar 11-12)

Light winds Sat look to tend N’ly as high pressure moves off the NSW Coast into the Tasman . There is a a trough approaching but a S’ly change looks to be confined to Sun, at this stage.

More small S swell for Sat, with a slight better period and quality expected and sets up a notch to 2ft+ at S facing beaches. N’ly winds off the coast (extending up to the lower Mid North Coast) whip up a small NE windswell for the a’noon.

A trough of low pressure off the Sydney area Sun, brings S’ly winds tending SE as the trough moves N during the day.  A small mixed bag of S swell and leftover NE windswell to 2ft offer up a few options early before winds tend SE. 

Next week (Mar13 onwards)

High pressure tracks quickly NE into the Tasman early next week and becomes elongated. We may see E’ly winds Mon turn NE and freshen during the day as it does so. The passage of a last frontal system through the lower Tasman over the weekend delivers a longer period S swell pulse Mon, along with potential building NE windswell. Expect some 2-3ft sets from the S and NE windswell potential. We’ll dial in size and timing for that during the week. 

The more N’ly position of the high pressure cell is a feature more typical of Spring than Autumn (see below) and it looks to continue a N’ly biased wind regime through to to mid next week at least, with small NE windswell a possibility.

An approaching inland trough system next week will be watched for any signs of low pressure development once the trough system reaches the very warm water of the Tasman Sea. 

In the mean-time looks like a lot of small S swell and NE windswell more typical of Spring than Autumn to get through.

Check back Wed for the latest.