Sydney Hunter Illawarra Forecast by Steve Shearer (issued Fri April 5th)

Features of the Forecast (tl;dr)

• Large E/NE swell Sat with strong, pre-dawn NE winds, easing and possibly tending NW-W (more likely north of Syd) depending on trough and formation of small low 
• Moderate sized, easing E/NE swell Sun with moderate N/NW tending W’ly winds ahead of NE sea breezes
• Long period S swell Sun, easing from Mon morning
• Smaller E/NE swell Mon, holding in at low levels into Tues/Wed
• Clean Mon wth light winds, light winds into Tues AM before robust S’ly change
• Spike in S swell Tues PM, as low forms off South Coast
• Strong S swell Wed, tending S/SE and slowly easing through Thurs/Fri
• S’ly groundswell pulses likely from next weekend into early week after- check back Mon for latest revisions

Recap

A bit of S-S/SE to 2-3ft swell in the water yesterday but strengthening onshore S/SE-SE winds made surface conditions a mess. Winds are relatively light this morning but onshore as a trough system moves down the NSW coast. Those winds will strengthen from the E through the day and make conditions a write-off. We will see stormy short range surf build through the day to 4-5ft as the local winds feeding into the trough whip up windswell. 

Onshore winds and building swells

This weekend (Apr 6-7)

We’ve got large peanut shaped high centred over Tasmania with lobes in the Bight and Tasman Sea. The moist onshore flow from this set-up is flowing into a coastal trough and interior low bringing onshore winds and rain. We’ll eventually see the low clear the coast bringing better winds Sun with some strong S swell pulses on the menu from Sun and into next week from Tasman Sea and deeper sources.

Tricky wind for Saturday’s outlook. The inland low and coastal trough focus strong onshore E/NE winds onto the coast through the morning so expect very poor, stormy conditions for dawny. Plenty of size expected in the 6 occ. 8ft range though. We may see a small circulation form around coastal Sydney which would offer offshore winds to the North of it. At present the Central Coast and Hunter look more likely to see offshore NW tending W/NW-W winds from mid/late morning onwards. Any small movement of the low circulation could see that extend down to Sydney so keep tabs on local winds if you can. Any small circulation that does form looks to dissipate back into the general trough line so winds are likely to tend N-NE again in the a’noon. 

It’s a highly dynamic, fluid system so if you can keep tabs on local winds there is a chance of scoring, with the caveat that local winds may not co-operate.

Sunday looks a safer bet as the low exits the Gippsland coast and a light/mod offshore tending variable flow becomes established. This should clean things up pretty quickly but size will have decreased as the local fetch contracts southeast-wards. Expect surf from the E-E/NE to 4ft, easing back to 3ft during the a’noon under sunny or clearing skies. Also in the water Sun will be some extra long period (18-20 second) S swell generated by a storm force low passing well to the S. There’ll be a range of wave heights but S facing beaches should see some 3-5ft sets with some bigger 6ft outliers possible at deepwater adjacent reefs. 

Next week (Apr 8 onwards)

Lingering troughiness and light winds for Mon with morning offshores tending to light S-SE breezes in the a’noon. The fetch of winds feeding into the trough will have retreated but should hold 3ft of E swell, easing a notch during the day. S’ly groundswell will be on the wane but some early 3-4ft sets at S facing beaches should be super clean, before easing during the day.

Those light winds continue into Tues morning so get in early for some clean 2 footers. We’ll see a front combine with the lingering troughiness to potentially form a surface low in the Tasman on Tues. Under current modelling  we’d expect strong S’ly winds to develop by lunch-time and the proximate fetch of these winds will whip up a fast rising S swell, potentially reaching 4-5ft by close of play at S exposed breaks. Smaller surf at sheltered spots. 

Strong S’lies again for Wed as the low potentially strengthens and the fetch elongates through the Tasman. There’s still some model uncertainty here so we’ll see how it looks Mon but for now we can pencil in strong S swell to at least 6ft, bigger 8ft at S swell magnets and smaller at spots protected from the S’ly wind. Small E swell will also be in the mix likely to 2 occ. 3ft.

We should see plenty  of S/SE swell for Thurs, with a slow easing trend in play for Fri and into the weekend as the low slowly drifts NE towards the North Island. We’ll revise on Mon but size in the 4-6ft range for Thurs , easing to 4ft for Fri is on the cards.

Further ahead we’ll see strong frontal activity below the continent and steered up into the far lower Tasman next week bringing S’ly groundswell pulses. We’ll see how they shape up on Mon but next weekend is looking good for S’ly groundswell with light winds and that pattern should extend into early week beginning 15/4.

Check back Mon for the latest and have a great weekend!