Lots of surf this week with improving conditions
Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon Sep6)
Forecast Summary (tl;dr)
- ENE tradewind swell pulses at low levels through this week though overshadowed by stronger S’ly swells
- Large S swell Mon, easing Tues with fresh S'ly winds, abating through Tuesday
- Longer period S swell fills in Wed, eases Thurs with good winds
- Small S pulse Fri
- Small S swell Sat, easing Sun, stay tuned for revisions
Swells from across the compass rose since Friday's F/cast. Sat saw small levels of NE windswell, at the lower end of f/cast expectation with generally 2-3ft surf, and light NE winds, which tended NW late in the day. Sunday was small most of the day with small signal of E/ENE tradewind swell in the 2ft range. A very swift rise in local S swell occurred late in the day (after dark in most places) as a complex low and cold front moved offshore from the far South Coast. That has seen wave heights rocket up into the 6ft range at S exposed spots, bigger 8ft+ on the Hunter, with small levels of E swell providing backup energy in more sheltered spots. Conditions are wild with strong SW to S’ly winds across Central/Southern NSW.
This week (Sep 6-10)
Plenty to look at on latest ASCAT (satellite windspeed) passes. A complex low in the Central Tasman is driving severe gale to storm force winds adjacent to the Central NSW coast and this is whipping up a large, local S swell, currently building across the region and expected to peak late today/this evening in the 6-6ft range, bigger 10ft on the Hunter. Surfing is being confined to more sheltered spots where size is in the 3-5ft range.
To the East a persistent, broad E’ly tradewind fetch is slowly contracting Eastwards, although windspeeds have been increased along the northern flank of a large high by an area of low pressure. This system has really been a better swell producer for areas north of Seal Rocks but background mid period E’ly energy will chug along for a few days, yet, in a very slowly diminishing signal. Most notably in more sheltered areas.
This E’ly energy is likely to be completely swamped by more strong S’ly energy however, so take the E’ly swell predictions with a grain of (sea) salt.
Wave heights will back down from overnight peaks through Tuesday but it’s still going to be a large and woolly day, likely overpowering most open stretches for the early with 6-8ft surf expected, bigger 8ft on the Hunter. Morning winds should be offshore, as the low and frontal system migrate further E towards New Zealand and pressure gradients ease, although mod/fresh S’lies are still expected through the midday to a’noon session. Seeking shelter from the wind will mean sacrificing size but there should be plenty of fun to be had in more sheltered spots with the energy on offer.
By Wed, a large high that is now in the Bight will begin nosing out into the Tasman, with more settled wind conditions expected. Models show a small cell breaking off the main high pressure cell, which is likely to lead to NE seabreeezes developing but offshore breezes should extend through the morning, becoming variable through the midday.
This is good because another strong pulse of S swell is expected to fill in Wed. This swell will be generated by a deep low centred around 50S which is expected to track south of Tasmania, with a slight NE wobble as it transits the Tasman on Tuesday. This is a powerful storm, with storm force winds and a large area of seas in excess of 30ft, and as a result swell periods will be in excess of 15s which will produce some real bathymetric focussing effects on deepwater reefs through Wed PM as swell trains get tripped up. Based on current modelling I think we can upgrade this swell to 6ft sets through Wed PM at S facing beaches, smaller 3-5ft away from direct exposure. Bigger 6-8ft surf is possible at select bommies and reefs with straight S exposure, not to mention Cloudbreak when it reaches there on Fri.
Wednesdays pulse then backs down through Thurs with early 3-5ft surf, easing back through the day. Solid surf at S facing beaches early will be primo with all day WNW to W winds expected as high pressure drifts NE and Central NSW comes under the synoptic influence of a cold front sweeping below the country. Thursday looks really good for most open beachbreaks and exposed reefs.
The initial winds in the cold fronts sweeping below the Tasman Wed/Thurs are very zonal but more favourable S’ly component winds are in the tail end of the fetch as it transits the Tasman, pushing up as a weak front through early Fri.
A small pulse of S swell is expected Fri from this source, likely in the 3ft range, though there is some model divergence on the strength of the fetch so revision is likely.
Winds look great to end the working week with light offshores tending to light E’ly seabreezes.
This weekend (Sep 11-12)
Small fun waves on offer for this weekend, especially Saturday with leftover S swell and some stray E swell, all up offering some clean 2-3ft beachbreaks with with a light NW pre-frontal flow expected, possibly tending to freshening NE winds in the a’noon.
Sunday is under a bit more dispute. A front is expected to push a S’ly change up the coast.
GFS anchors this front to a large and powerful low in the lower Tasman, while EC has a much more modest front pushing into the Tasman.
At any rate, Sunday is likely to start off small with freshening NW winds so if you’ve got plans for a go out best to make them for the early.
Next week (Sep 13) and beyond
We can rule out action from the East next week, and models are diverging on activity from the South, although a very active storm track in the Southern Ocean below Australia suggests more swell activity for the region from this quadrant, details to come.
S swell is expected Mon 13, large according to the GFS scenario, much more modest according to EC.
With so much swell expected this week, we can afford to set our focus on the short term and come back later on Wed and have a look with fresh eyes at next week.