Sydney Hunter Illawarra Forecast by Steve Shearer (issued Fri April 26th)

Features of the Forecast (tl;dr)

• Minor background E/NE swell offering up the occ. 2ft set, persisting into the weekend
• Clean conditions Sat AM with quality S swell on offer- light winds most of the day
• Easing surf Sun with light AM winds and freshening N’ly breezes PM
• Small to start next week
• Dynamic outlook next week with potential trough deepening into low in Tasman- possible steep increase in S/SE swell Wed
• More S swell possible next weekend if low redevelops in Tasman
• Low confidence in specifics due to model divergence so check back Mon for latest

Recap

Around 2-3ft of S swell yesterday, bigger on the Hunter and true S swell magnets with glassy/lumpy surf through the morning as offshore breezes tried to clean up S’ly bump. We’ve got offshore winds again this morning before S’lies kick in with similar glassy/lumpy/raw conditions and size in the 3-5ft range at S facing beaches on a building trend. 

Raggedy building S swell

This weekend (April 27-28)

No great changes to the weekend f/cast. High pressure moves over NSW o/night into tomorrow, with pressure gradients relaxing along the coast. Morning winds should still have a slight S’ly bias to them (W/SW-SW) but be basically offshore for most spots. A mix of mid period and longer period S swells will be in the water with surf to 3-4ft and the occ. bigger 5ft set. We’ll see a slow easing trend after lunch but with light variable breezes on offer surf should stay fun/rideable all day.

Glorious conditions for Sun morning with light offshore winds, tending to a’noon N’lies which will kick up to moderate paces through the a’noon. Surf will be down on Sat but there’ll be enough leftover energy for some 3ft sets at S facing beaches, easing through the day. Both days will see some minor E/NE swell in the water offering up the occ. 2ft set- good for kids and beginners.

Still looking good for the weekend, especially Sat as high pressure moves across Southern NSW and light winds establish. We should see light land breezes both days, with a slight S’ly bias Sat (W/SW-SW) and more true W’ly Sun, with a’noon E’ly breezes Sat, tending NE on Sun.

Sat still has plenty of leftover S swell, a mix of mid and longer period stuff with sets still in the 4 occ. 5ft range but easing through the day. 

By Sun we’ll see much less energy in the water, offering inconsistent 3ft sets at S facing beaches, dropping back to 2ft or less through the day.

Both days will see traces of E/NE swell but it’s not likely to be a useful swell source, just the odd 1 to occ. 2ft set.

Next week (April 29 onwards)

There’s now quite a bit of model divergence around next week as potential troughiness and low pressure looks likely in the Tasman Sea.

Nothing much Mon- we’ll see NW winds tending NE as high pressure sits in the Tasman and a trough/front approaches from the W. Just small background energy from the E/NE and S offering up a few tiny waves (1-2ft at best) with clean options across most beaches.

Things get interesting/dynamic from Tues. At issue is a trough and potential surface low in advance of a major high pressure ridge. At a minimum, the trough will charge up a SE surge along the NSW coast with an increase in S/SE-SE swell later Tues and into Wed. A front passing below the continent will add S’ly groundswell to that mix. 

ECMWF model then suggests the trough moving northwards, bringing the SE surge right up into SEQLD/Fraser coast coast water and leaving a SE flow behind on the NSW Central Coast. EC then suggests the trough deepening into a surface low off the North or Mid North Coast, with an increase in SE-E/SE swell focused on that area through Sun.

GFS has the trough deepening much further south through Wed into Thurs with a sizey S/SE swell developing through Wed into Thurs, potentially with offshore winds developing Thurs as the low moves southwards, before potentially redeveloping and generating a large S swell from the return flow later Sat or Sun.

A trough north of the North Island looks to redevelop into a sub-tropical low and intensify on the edge of the swell window early next week (see below), favouring the sub-tropics for nice pulse of quality E-E/SE swell but also offering a potentially good day Fri for temperate NSW, winds depending on developments in the Tasman Sea.

Until we get a better handle on where this potential surface low forms confidence remains extremely low as to specifics so make sure you check back Mon for the latest.

See you then and have a great weekend!