Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Wed 11th May)

• Forecast Summary (tl;dr)
• E/NE swell starting to build later Wed, becoming chunkyThurs and peaking up Fri easing Sat/ Sun
• Winds mod/fresh NE through this period, potentially improving Sat, with offshore winds Sun, stay tuned for updates
• Quiet start to next week, with S swell on the cards for later in the week

Recap

Surf has deteriorated over the last 24 hrs as a deep onshore flow becomes established. There was a clean window yesterday morning with generally 2-3ft of surf from the E’ly quadrant before onshore winds kicked in and blew it out. Today has seen a more generalised deep, onshore flow with messy 3ft surf across the region. 

Cleanish and building from the E/NE

This week (May 9-13)

No great changes to the front end of this weather/surf event, which is starting to kick into gear now. The latter stages have been wound back a few notches, reducing the expected wave heights over the peak of the swell, so let’s take a look at it.

A large 1037 hPa high is occupying the Central Tasman Sea with a solid ridge established along most of the East Coast. A long interior trough and developing trough/low off the North QLD coast are tightening the pressure gradient along most of the ridge, bringing fresh onshore winds and a deep E’ly pattern to the majority of Tasman Sea and Central/Southern Coral Sea. An expected surface low forming off the North QLD coast now stays further north and contracts NE towards New Caledonia during Thurs/Fri (see below), making this event even more QLD focussed.

In the short run, the high moves out further and faster than modelled on Mon, bringing a quicker shift to the winds to the NE to N, which will open up a few more spots. Expect a building trend in E/NE swell through Thurs, pushing up from 4ft up into the 4-5ft range during the day. 

N to NNE winds stay fresh during Friday 13th. There is a chance they may lay down a notch during the a’noon and even tend NW, although it’s still a line ball call depending on how the inland trough behaves. Keep tabs on local winds through the a’noon. Surf-wise we’re looking at 3-5ft of E/NE swell, a fair bit down on size from Mon’s forecast as the majority of the fetch remains well north in the Coral Sea. Some traces of long period S swell will be in the mix as well with sets to 2ft at S swell magnets, though it’s a flukey source and won’t show everywhere. Still plenty of energy on hand though to end the working week. 

This weekend (May 14-15)

Well, no major NE swell this weekend with the fetch contracting north into the Coral Sea but still a lot of fun surf to be had. We should see an early NW flow through Sat morning before winds tend N, possibly swinging back NW in the a’noon. 

Size is going to come down a notch from Fri, as we revert back to a more normal mid period NE windswell. Expect 3-4ft sets, easing back a notch during the day.

Sunday still looks great fun, as we get a clearing W’ly from the trough and a front passing through. Light W’ly winds will groom E/NE-NE swell in the 3ft range, easing back during the day. Expect a light seabreeze in the a’noon.

Next week (May 16 onwards)

Quiet start to next week now with the expected frontal activity being shunted southwards and the winds now quite zonal (W-E). 

Weak high pressure in the Tasman is likely to see a few days Mon-Wed of light winds and tiny surf. Mon will see small leftovers in the 2ft range before surf drops right back into the 1-2ft range through Tues and Wed. With light winds expected, there’ll be some clean babyfood on offer for beginners and logs.

Models are still divergent on fronts passing through the lower Tasman next week which suggests we could be in for substantial revision on Fri or Mon.

At this stage we’re looking at frontal passages of mostly zonal winds through mid next week, suggesting small/mod S swell by Fri next week. Winds are still up in the air so we’ll review that on Fri.

Seeya then.