Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri Dec3 )

Forecast Summary (tl;dr)

• Small increase in junky S windswell Sat PM with S'ly winds
• Slightly more S swell Sun with S'ly winds tending E/SE, E'ly in the PM
• Fun sized E/SE to E swell Tues/Wed, easing Thurs with periods of light winds AM
• S'ly change Wed
• Small, persistent long range E swell from Fri into Sun
• Likely surface low off coast next week with potential for steep increase in S swell Fri and solid S to SE swell next weekend, stay tuned for updates

Recap

Small surf has maintained surfable waves not exceeding 2ft since Wed, with yesterday slightly bigger than today. Conditions were workable with periods of light winds best in the morning,  although large pre-New Moon high tides in the morning confined the best waves to shories. Clean conditions early this morning under light NW winds are now being scuffed up by a S’ly change working it’s way up the coast. The trough bringing this change will be overtaken by a stronger front on the weekend, which will see stronger S’ly wind establish tomorrow. Details below.

This weekend (Dec 4-5)

No great changes to the weekend f/cast. A front associated with a dual centred low passing to the South of Tasmania later tonight and through Sat does most of the heavy lifting as far as swell generation is concerned.

Swell from that source doesn’t really fill in until Sun, accompanied by a mod/fresh S/SE flow as a high pressure ridge rapidly builds in behind the front.

Saturday is expected to be small, with small, short period ENE’ly swell trains through most of the day, and a very modest changeover to short period S’ly windswell during the a’noon, once S’ly winds kick in.

Best conditions will be early, with a more variable, light SW to S’ly flow. So if you’re keen for a go out hit it early with an appropriately floaty board.

Sunday will have more size. Expect some short period S’ly swell in the 2-3ft range, bigger 3ft on the Hunter but with winds from the same direction it’s going to be a real mess across most open stretches with S’ly swell exposure. There’s a tiny trace of longer period S swell in the mix, presumably generated by stronger winds in the front as it reached peak strength SW of Tasmania through today. That may enable some surfable babyfood at more sheltered spots but it’s best to keep expectations very low for Sunday. 

Next week (Dec6) and beyond

Onshore winds are going to be the headline feature to start off next week. Dominant High Pressure will be sitting smack bang in the middle of the Tasman Sea, with a firm ridge up the coast. A trough of low pressure in the Northern Tasman which has been a semi-permanent feature of the synoptic chart for the last 2 weeks concentrates a fetch of SE/ESE winds aimed more at sub-tropical NSW.

Thus the f/cast region sees close to a straight E to ENE flow through Mon with a scrappy signal of short period ESE swell in the 1-2ft range, possibly building into the 2ft range during the day.

Tuesday looks a better bet. The trough of low pressure in the Northern Tasman, dips southwards, with the fetch aimed more directly at Central NSW, albeit as it weakens. This is likely to see some fun surf from the E’ly quadrant in the 2-3ft range, likely pushing up into the 3ft range during the day. Winds tend NW to N as the high drifts E of New Zealand and the ridge breaks down. That opens up more options for a fun wave. 

Surf from that source maintains a fun sized 3ft through Wed, with NW winds in the morning. A S’ly change is due Wed, as another trough pushes up the coast and a front and parent low pass to the South of Tasmania. Current modelling has the change through in the morning but timing is likely to change so keep a session pencilled in for Wed, contingent on the timing of the change.

Once again, from mid next week uncertainty ramps up and error bars widen as models diverge. 

We’ll sketch out the pattern now, expecting to finesse minor or major details on Mon.

Strong high pressure moves E to be well south of the Bight by mid next week. An intrusion of cold air is expected to form an upper cold pool, leading to instability and the development of a surface low as the upper trough interacts with the Tasman trough, later Thurs or Fri. There’s a possibility this low may be an ECL or have characteristics similar to one, potentially including severe weather. 

Models diverge on the timing, position and strength of a surface low (possible ECL) off the coast by Fri next week. Based on current modelling we’re looking at a solid increase in S swell through Fri PM, with a provisional size in the 5-6ft range.

With a strong high south-west of Tasmania and low pressure in the Central Tasman that sees excellent odds for a solid weekend of S, tending SE, then E/SE swell, with SW winds moderating and tending light S to SE as the low moves away. 

A distant, but persistent low well to the E/NE of the North Island forming this weekend is also expected to supply some longer period, long range E swell during next weekend but if the low kicks up off the Central NSW Coast as modelled these swell trains will be overshadowed by the dominant, more proximate swell generated by the close range system.

Small changes in timing, position of the low and strength and orientation of wind vectors in the fetch will have compounding effects on surf size and quality, so with such a long lead time before the system develops we can only sketch out the rough outlines of the swell generating potential.

Check back Mon for a full update and a have a great weekend!