Extended forecast

Effective from: Fri 3 Feb '12, 09:00AM

Forecast prepared by Craig Brokensha
Next update Mon 6/2 1pm.

Previous day's summary:

Wednesday afternoon's strong increase in S'ly windswell and groundswell peaked around 5ft across south facing beaches during the afternoon. This swell then eased overnight, coming in at 3-4ft across south facing beaches yesterday morning, with 2-3ft waves across open locations before easing a touch further into the afternoon. Conditions were poor during the morning with fresh and gusty SE winds, but these tended more S'ly later in the day, cleaning up protected southern corners.

The surface trough responsible for the S/SE windswell Wednesday afternoon, and yesterday's E/SE windswell drifted south of Sydney overnight resulting in winds swinging offshore this morning. This cleaned up a fun and peaky E/SE and S'ly swell that came in at 2-3ft across most beaches. We should see the swell fading a touch during the day as winds remain favourable.

Swell events within the forecast period:

1) Small levels of E/NE trade-swell building slowly tomorrow ahead of a stronger pulse Sunday, peaking Monday afternoon
As talked about throughout the week, we should see open beaches increasingly gradually in size during the weekend and further Monday owing to tropical developments to the north of New Zealand. Initially a broad easterly ridge was generating a fetch of strong easterly winds throughout the northern Tasman Sea. This has produce a small and inconsistent E/NE trade-swell for today and tomorrow that should come in at an inconsistent 2ft across open beaches.

The ridge contracted to the north-east later this week and was positioned north of New Zealand's North Island. Winds have been strengthening through this ridge though as an active monsoon trough in the Coral Sea spawned a series of small but intense embedded low pressure systems around the Fiji, Vanuatu and New Caledonia region.

One of these embedded lows is forecast to slowly retro-grade back down the west-southwest towards the East Coast during today, Saturday and Saturday. All the while generating winds in the strong to gale-force range out of the E/NE on an already active sea state.

A strong pulse of E/NE groundswell is expected off this west-southwest movement of the low that should build through Monday and reach an inconsistent 3-5ft across open beaches during the day. Before this pulse of bigger swell, smaller levels of E/NE swell will develop across open beaches over the weekend owing to the earlier stages of the weather system. A slight increase to 2ft+ is expected late tomorrow, with stronger 2-3ft waves on Sunday morning, increasing further towards 3-4ft by late in the day.

Although the swell will peak on Monday afternoon, it should hold into Tuesday morning at a similar 3-5ft across open beaches as a fetch of strong E/NE winds remain near stationary through the central Tasman Sea during Sunday evening and Monday morning. A drop in size should occur into the afternoon though and further Wednesday from 2-3ft+ across open beaches as the fetch breaks down into Monday evening and Tuesday.

Conditions throughout this swell event will be favourable at times and mainly during the morning's. Light W'ly winds are expected tomorrow morning ahead of afternoon sea breezes, with Sunday morning seeing light W/NW winds ahead of a moderate to fresh afternoon NE'ly. As the swell pulses on Monday winds look to be a little funky, with a morning N/NW'ly likely to tend variable ahead of a fresh S/SE change at some stage during the day. The models are divergent on the timing of this change still but it should be in by the late afternoon. In either case keep an eye on your local wind observations to find the best window to attack this swell. Tuesday unfortunately looks to see fresh S/SE winds persisting across the Sydney Coast, with an outside chance for early S/SW winds. Wednesday looks to offer cleaner waves again with a light SW'ly during the morning ahead of SE sea breezes.

2) Medium sized S/SE windswell building Tuesday and further Wednesday while tending SE, steadying Thursday
The surface trough linked to Monday afternoon's S/SE change will stall off the Sydney coast during Tuesday and Wednesday while producing a strong fetch of SE winds. This should produce a building windswell to 3ft+ across south facing beaches on Tuesday before tending more SE during Wednesday and pulsing further to 3-4ft. The swell is likely to hold into Thursday but we'll review this again on Monday.

Long term forecast (6+ days):
The longer term outlook remains active, with the medium sized SE swell for Thursday next week ahead of an easing trend on Friday. Beyond this we are likely to see a small pulse of NE swell next weekend ahead of a building S'ly swell later in the weekend as a low pressure system deeps off the South Coast, but we'll confirm this on Monday. In the meantime have a great weekend!