Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Wed 18th Oct)

Features of the Forecast (tl;dr)

• Easing swells Wed, with swells tending more S/SE-SE into Wed
• Light winds and fun sized SE-E/SE swell pulse Thurs, bigger in the a’noon
• Easing E/SE swell Fri with light winds tending N’ly through the day
• Small Sat AM with developing NE windswell PM
• Plenty of NE windswell Sun AM, with offshore winds likely, swell easing PM
• S swell spike Mon PM, peaking Tues with light morning winds
• More S swell late next week- check back Fri for revisions

Recap

Plenty of robust, windy S swell yesterday as a low pressure system moved NE into the Tasman. Not a great deal of quality but size in the 4-5ft range, bigger 6ft+ on the Hunter with just a brief window of semi-clean conditions under an offshore flow before fresh S’ly winds kicked up. That initial surge of S swell has backed down into today with size to 4ft across the region and mostly choppy conditions under S/SE-SE winds.

Some swell getting into sheltered bays but still wind affected 

This week (Oct 18-20)

The synoptic set-up looks quite unseasonal at the moment with a 1031 hPa high drifting over NSW and a 1007 hPa low slow moving in the Tasman west of the North Island. Current ASCAT (satellite windspeed) passes show broad fetch of mostly strong S-S/SE winds with some embedded low end gales reasonably well aimed for East coast swell production. 

In the short run we’ll see winds ease overnight and tend to land breezes in the morning as high pressure drifts over the region and pressure gradients slacken. Expect light W-W/NW winds tending to NE seabreezes in the a’noon. E/SE swell generated by the Tasman low fills in o/night and looks good for quality 3ft surf, likely filling in further during the day to 4ft+ with some bigger sets possible. Models are also picking up traces of long period S swell from a deep polar fetch, which may add some 2-3ft sets to reliable S swell magnets.

N’ly winds increase Fri as the high moves into the Tasman and a front approaches but we should see lighter NW winds inshore early. Thursday’s pulse of E/SE swell holds a few 3-4ft sets early before easing down through the day but we should still see 2-3ft surf hold through the a’noon under N-N/NE winds. 

This weekend (Oct 21-22)

Not much change for the weekend outlook- still expecting a freshening N-N/NE flow for Sat. The Tasman low lingers as it slowly weakens which should see a small, fading E/SE swell into Sat, in the 2ft range early. Through the a’noon a proximate fetch of N/NE winds will push NE windswell up into the 2-3ft range under fresh winds from the same direction.

Sunday morning is looking good. The NE fetch looks to reach maximum strength in the early hrs, perfectly timed for a W’ly change as a low/front approaches Tasmania. Under current modelling we should see W’ly winds in by dawn, or very close to it, with NE swell maxing in the 4ft range. This swell will ease back, slowly at first, then more noticeably after lunch as the fetch gets shunted eastwards so get in early.

Next week (Oct 23 onwards)

A vigorous but compact low moves East of Tasmania Mon, bringing W winds tending S’ly through the day.  Small leftovers to start with, and a late kick in new S swell is expected. Likely propagating up the coast later in the a’noon and reaching 3-4ft at S facing beaches, bigger sets on the Hunter.

The fetch is short lived and mobile but swells from the S should peak Tues morning in the 3-5ft range, with bigger 6ft sets on the Hunter. We’ll adjust size and timing on Fri but Tues looks to have favourable light morning winds tending N-NE in the a’noon. We should see a rapid easing in size through the a’noon.

Further ahead and we may see another round of NE windswell later Wed into Thurs as another frontal system approaches and tightens pressure gradients.

Models are in broad agreement on a broad frontal system mid next week which looks to supply a moderate S’ly swell late next week, Friday most likely. Winds look tricky to call at the moment.

As we noted on Mon, some early season tropical activity up near the Solomon Islands now looks set to deepen into a tropical depression, possibly even a very early season cyclone. Unlikely we will see any swell from it - EC has the system just trickling into the swell window as it peters out, while GFS runs it quickly off to the SE between New Caledonia and Vanuatu into the “graveyard”. 

We’ll have another look at it on Fri, but it’s far more likely we’ll see swell sources from more usual suspects for this time of year: NE wind swells and S’ly swells from frontal progressions passing through the Tasman.

Seeya Fri.