Effective from: Wed 23 May '12, 01:40PM

Forecast prepared by Craig Brokensha
Next update Fri 25/5 1pm.

Previous day's summary:
South facing locations continued to pick up infrequent 1-2ft sets yesterday under offshore winds while open beaches were tiny. The background S/SE swell continued to ease overnight leaving tiny 0.5-1ft sets across most open beaches today with NW winds.

Swell events within the forecast period:

1) Small to medium sized NE windswell building Friday, easing Saturday
Wave heights will remain tiny to flat across the coast tomorrow but a fresh NE swell should start to build through Friday as a deepening low pressure system moves across our state. This low is related to a deep pool of cold air shedding off a strong cold outbreak across the south-east of the country during tomorrow.

As this low nears the coast Thursday night and Friday an infeed of strong NE winds will be generated below the Hunter and Seal Rocks kicking up a NE windswell for Friday. North-east facing beaches should rise to 2-3ft during the day ahead of a peak overnight. The fetch will move offshore and away from our swell window Friday night as the low moves further east with the swell expected to drop from 2ft early Saturday from a more E/NE direction.

Winds on Friday will improve during the day with a fresh N'ly early expected to swing NW while Saturday will see fresh to strong W/NW winds tending straighter W'ly during the afternoon.

2) Medium sized S'ly swell building Sunday, peaking Monday with a smaller S'ly groundswell also in the mix
The models are finally converging regarding the development and movement of the surface low off our coast over the weekend and unfortunately it's gone the way of EC earlier in the week with it moving off fairly rapidly to the east during Saturday evening.

This will limit the size of the S'ly swell during Sunday afternoon due to winds around the western flank of the low being too westerly, but a secondary frontal system pushing up the southern NSW coast during Sunday should kick up a solid S'ly swell for later in the day ahead of a peak on Monday.

So at this stage Sunday morning is likely to start tiny to small but a rapid pulse in size late in the day to 3-5ft is expected across south facing locations. A broad fetch of gale to severe-gale-force S'ly winds aimed up though the southern Tasman Sea during Sunday should then produce a peak in size on Monday to 4-6ft across south facing beaches. Open beaches will see much smaller waves, especially on Sunday afternoon, only likely to 1-2ft+, while Monday should offer bigger 3ft+ sets.

As noted above a slightly smaller S'ly groundswell will also be in the mix later Sunday and early Monday generated by a vigorous polar frontal progression moving through our far southern swell window on Thursday evening and Friday morning. The size off this doesn't look to top 3ft later Sunday and 3-4ft early Monday before fading into the afternoon.

Now winds through Sunday as the swell builds will tend onshore from the S/SE after a morning W/SW breeze, with Monday looking less than favourable for locations picking up the most swell with a SW tending S/SE wind. The swell should ease while tending S/SE in direction from 3-4ft at south facing locations and 2-3ft at open beaches on Tuesday. Winds should be light from the SW during the morning with light SE sea breezes into the afternoon.

Long term forecast (6+ days):
A reinforcing S'ly groundswell should keep inconsistent 2-3ft+ waves hitting south facing beaches Wednesday morning while the rest of next week will see frontal systems steered up through the Tasman Sea. This should keep us topped up with small to medium sized S/SE swell for the end of next week, but check back here on Friday for an update on this and Sunday/Monday's swell.