Sydney Hunter Illawarra Surf Forecast by James Casey (issued Monday 22nd March)

Best Days: Large and messy until Wednesday. Smaller towards the end of the week. 

Outlook:

• Large NE swell peaking Tuesday late, biggest for the Illawarra and adding to the lingering E swell.
• Conditions cleaning up from Wednesday but swell dropping quickly too. 
• Smaller conditions for the end of the week with a few S changes 
•  

Recap

Well what a weekend it has been with hundreds of mm of rain across the region water quality and the victory at sea style conditions are the real story. If you surfed good on you for getting out there but I hope you don’t develop an ear infection. 

Basically winds were onshore for most of the weekend with a spike in swell heights late on Saturday and into yesterday afternoon. The water was brown. It was onshore. You might’ve found a novelty wave somewhere but all in all a mess out there. 

This Week

Now, when is it going to clean up?

Unfortunately not for a few more days. These E winds are going to swing around to the NE though but they will strengthen as the serious weather continues for a couple more days.

What’s causing all of the rain and onshore winds?

A series of troughs over the east coast are being fed moist onshore winds thanks to a strong ridge of high pressure over the Tasman. The high is positioned in the southern Tasman, slowly edging it’s way east. 

The slow moving nature of both the high and the troughs are exactly the problem. The longer they stick around the longer this rain will too. I’d expect at least another 100mm from the Hunter to Illawarra over the next two days. This means water quality will only get worse from what it is now. 

Now let’s dissect the incoming low from that looks to move off the coast tomorrow afternoon. 

Technically speaking it is an easterly trough low, not an east coast low. The difference? Well it’s only small but an east coast low moves slower and more parallel to the coast, while this system pushes offshore and south fairly quickly.  

Swell heights are expected to rise and do so quickly tomorrow afternoon out of the NE as the low starts to form and deepen, directing gale-force NE winds into the coast. This on top of an already active sea state will mean large waves across the region.

We will see 10ft sets for the Hunter and Sydney, larger due to the longer fetch for the Illawarra. Expect it to be a mess with gale force NE winds and heavy rain making it unpleasant to say the least.

For those big wave chargers chasing these systems, Wednesday looks to be the day but you’ll need to be quick. The sun will come out, winds will swing offshore and begin grooming the mess across the coast but wave heights will drop off fairly rapidly. Early on Wednesday will be the pick with 8-10ft sets out of the E/NE but it’ll drop to 4-5ft by the afternoon easing steadily thorughout the day. 

The easterly trough low shifting south of the region will create offshore winds for the coast. A broad high pressure system will move in behind it bringing some more stable conditions for the end of the week. It’ll allow us to dry out and for water quality to clean up too but I wouldn't be surprised to see the brown water remain into the weekend. I'd also keep your eyes peeled for any debris in the water too, there's a lot of water flowing out of the Haweksbury River, Sydney Harbour, Hunter River and all other estuaries. 

The end of the week

By Thursday it’ll be around the 3-4ft mark with just lingering E/NE energy from the previous system. Offshore winds will make conditions much cleaner than what they have been.

A coastal trough will create a weak S change along the coast on Friday morning. The swell will only be small though, let's call it 2ft+, but winds will freshen out of the S. There'll also be a bit more rain but nothing like we are experiencing at the moment. 

Winds will shift back offshore on Saturday as a stronger S change approaches for Sunday. NW winds and a small S swell will combine on Saturday before the S change arrives on Sunday. 

Sunday won’t see much of an increase in swell but Monday will see it rise a bit as a mid period S swell pulses along the coast. It doesn’t look to provide anything of too much substance but it’s a fair way out so let’s just keep an eye on it for now.