Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon Sep20)

Forecast Summary (tl;dr)

• Rapid increase in windy, low quality S swell Tues, with strong/gale force S'ly winds developing.
• S swell peaks Wed morning with a possible brief window of cleaner conditions before S'ly winds blow up
• Mix of easing S swell Thurs with some small, longer period S swell and light winds and a'noon seabreezes
• More long period S swell Fri AM, with clean conditions
• Small long period S swell Sat, stronger pulse Sun, hampered by S to SE winds both days
• More S swell pulses likely early/mid next week
• NE windswell potential mid next week

Recap

Fun weekend of waves with some tricky wind shifts that offered up windows of opportunity for the savvy. Saturday saw strong leftover ESE swell in the 4ft range, messy through the morning and early a’noon, before a W’ly wind change cleaned things up and offered up a good afternoon session. Surf dropped through Sunday with mostly leftover 2-3ft waves and clean conditions under light NW winds. A sneaky pulse of S swell from a Bass Strait fetch provided a few fun 2-3ft waves on Sunday a’noon. Size has bottomed out today with exposed coasts maxing out at 2ft, 1-2ft being the most common size at open beaches in the region and clean conditions continuing with light land breezes before a fresh SW change extends up the coast. 

This week (Sep 20-24)

A strong SW change is making it’s way up the coast as we speak but the coast-hugging low and subsequent over-sized S swell disappeared from model runs over the weekend. Models have swung back to the original EC resolution which sees a rapid-fire, coast-hugging fetch of strong to gale force SW to S winds through tomorrow before the fetch thickens up overnight Tues and then weakens and moves away during Wed. Following this rapid spike in wind and swell the week settles down quickly as strong high pressure moves in from the Bight across the south-east interior and becomes flabby, leading to settled conditions and small surf to end the working week. A semi-stalled polar low at Tasmanian longitudes through the middle of the week will send a variety of long period and mid period S swell trains our way through the end of the week and over the weekend.  Read on for details.

By tomorrow morning the front will be generating strong SW to S winds, possibly gale force by the a’noon, with a low developing in the far Eastern Tasman sea anchoring the pressure gradient squeeze as a large high drifts in from the Bight. Surf will build rapidly through the a’noon, but quality will be low. This is very localised S’ly windswell generated from the proximate coastal fetch so don’t expect too much size to get into sheltered corners, as open stretches build into the 5-6ft range during the a’noon at S exposed beaches, much smaller elsewhere.

Mid period S swell peaks o/night and early morning Wed, with 4-5ft surf through the morning, easing during the day. The frontal fetch and low in the Eastern Tasman are all drifting away but the ridge of high pressure is expected to maintain S’ly winds along the coast during Wed. SW winds early will open up a few more spots but there’ll be plenty of lump and bump at exposed S facing beaches Wed, so you’ll need to sacrifice some size to find clean conditions. 

Thursday looks the first proper clean day as high pressure weakens and moves up into sub-tropical latitudes, bringing a light land breeze with a northerly component, which trends to a NE Seabreeze. The trend in Tasman sea generated S swell will be down, with the morning offering the most size, likely 3ft at S facing beaches and some 4ft sets on the Hunter. Wave models are picking up some S swell trains from the vast array of complex wind fields expected to be resident beneath Tasmania and a gale force fetch out of Bass Strait overnight Wed into Thursday morning. Despite the off axis nature of these fetches, aimed almost 180 degrees away from the East Coast, the sheer width of the source fetches is likely to see refraction back  into the East Coast. 

Thursday a’noon doesn’t look particularly impressive but it’s likely worth some 2-3ft sets at S facing beaches through the a’noon, with N to NE winds becoming moderate up to dark. 

Winds become more frontal and W’ly dominated during Fri, with some small, but longer period S swell trains in the water generated by intense W and even W/NW fetches operating on an active sea state under the country Tues/Wed. These swell trains are likely to be quite particular as far as swell focussing goes, so you might need to put the thinking cap on to get the best out of the size on offer. Certain beaches are likely to be close to flat, but reefs and swell magnets with S swell exposure could easily harvest some 3ft surf on Fri with the Hunter coast likely to see stronger 4ft surf through Fri, possibly 4-5ft through the a'noon. Expect a late, light Seabreeze during the a’noon.

This weekend (Sep 25-26)

South swells on the menu this coming weekend, although winds are looking ordinary as a front passes through the Tasman and a high pressure ridge quickly builds a S’ly flow along the coast during Saturday morning. 

The front is associated with the deep, complex polar low finally moving along with broad fetch of SW gales covering the lower Tasman. 

Swell from that source is expected Sun, swells from an earlier incarnation of the low generate smaller S swell for Sat, building through the a’noon into the 3-4ft range at S facing beaches, after a smaller start to the day. Unfortunately, that will arrive with developing S to SE winds so it’ll be hard to find a clean or even semi-clean wave without giving up a lot of size.

Stronger S swell from the passage of the front and low across the Tasman is in the water Sunday, likely in the 3-5ft range at exposed S facing beaches, but continuing S to SE winds will make life difficult to find a clean wave. A window of cleaner conditions is possible Sunday morning and we’ll update that on Wed. Otherwise, you’ll need to find some shelter from the wind and give up size. Longer period swell trains in the mix will help with refraction into more sheltered Bays. 

Next week (Sep 27) and beyond

High pressure moves into the Tasman early next week as the intense frontal activity below Australia winds back a notch. GFS suggests a weak, but long and broad area of SE winds through the Central Tasman which would offer a couple of days of small SE swell early next week, as well as another small S swell pulse Mon.

Both major models prog some weaker cold fronts passing below Tasmania early next week, suggesting more small S swell pulses into the middle of next week. The high is likely to drift into Spring-time positioning, with developing N to NE winds by mid next week, possibly strong enough to generate some local NE windswell.

Check back on Wed and we’ll update that upcoming pattern as well as the rest of the week and weekend.