Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Wed 29th March)

Forecast Summary (tl;dr)

• Variable-NW-W winds Wed
• Inconsistent S swell Wed 
• Small SE-ESE swell Wed PM
• Low point Thurs with a possible late kick in new S swell and SW winds tending S'ly PM
• Mid period S swell fills in Fri with offshore morning winds
• Flukey SSE groundswell Fri
• S’ly winds this weekend with small S swells, a notch bigger Sun
• Small, benign conditions now set in most of next week
• Tricky outlook for later next week, possible larger S swell on the radar, check back Fri for revisions

Recap

Inconsistent but long-lined S swell came in Mon a'noon and extended into Tues, over f/cast expectations with most S facing beaches in the 3ft range before easing. Conditions were primo under a light/variable tending NW flow. Today has seen surf slow down more with inconsistent 3ft sets on offer for the patient under clean morning conditions . A small amount of SE swell spread off a fetch aimed at Tasmania is likely to see some 2-3ft sets later today.

Smaller and slower today but still the odd set

This week (Mar 29-31)

Still a complex, troughy pattern in play with a slow moving trough of low pressure drifting south off the Gippsland coast towards waters East of Tasmania. A front sweeping in behind the trough is bringing a clearing W’ly flow through temperate NSW today, reaching the sub-tropics tomorrow. A belt of high pressure below the continent is now weakening and setting us up for a more benign pattern compared to Mondays notes. Small S swell pulses are on the menu from this frontal activity.

In the short run we’ll see an extended period of W-SW winds through tomorrow morning with widespread groomed conditions (some S facing beaches may have a little bump on them). As the trough of low pressure deepens East of Tas we’ll see the return S’ly flow extend Northwards up through the region. Small S to SE swells, mostly SSE-SE from a decaying fetch off the South Island and radial spread from the fetch aimed at Tasmania will see surf in the 2-3ft range. A small kick in new S swell is likely through the a’noon, especially in the south of the region.

Friday sees more of this new mid period S swell building in during the day, up into the 3ft range at S facing beaches, along with some longer range SSE  swell adding in some inconsistent 2-3ft sets. Winds look to back down quickly through Fri as the low moves away and the area comes under the sway of weak local pressure gradients. Offshore winds should extend well into the late morning before tending to variable breezes in the a’noon.

This weekend (Apr 1-2)

Another small front pushes up past Cape Howe overnight Fri into Sat, re-energising the S’ly flow for Sat, although a period of W-SW winds is on the cards for the early. Fridays increase extends into Sat morning, looking fun enough with 3ft at S facing beaches. S’ly winds looks to freshen during the a’noon with a late kick in size on the cards as the main body of the deeper SSW-S fetch clears Tasmanian longitudes Fri/Sat. 

Sun will see a morning peak in size from mid period S swell, generated by a reinforcing front Sat AM, with sets to 4ft likely at S facing beaches. Winds look problematic with a S-SSE flow well set in and any morning SW flow likely to be brief and restricted to areas north of the Harbour to Central Coast. An easing trend in size is likely through the a’noon and we should see winds lay down a notch as pressure gradients ease. Not enough for open beaches to clean up but worth a scout at places with some wind protection.

Next week (Apr 3 onwards)

As mentioned, more benign conditions are now more likely for next week. High pressure moves quickly into the Tasman Sun into Mon and an expected surface trough off the Mid North Coast now looks less likely, with an elongated weak trough hovering parallel and close to the NSW Coast.

South swell looks to dry up quickly into Mon, with just small leftovers on offer. The high in the Tasman and parallel trough looks set to deliver a couple of days of N-NE winds and small, weak E-NE swells in the 1-2ft range. 

The trough looks to spawn a small low off the South Coast/Gippsland region, dragging an offshore flow with it, so we at least should see clean conditions through most of next week, at least Tues-Thurs under current modelling. 

Into the end of the week and leading models differ greatly on expected outcomes. GFS suggests the low will be absorbed by a much stronger front and low forming a powerful progression of SW-S winds in the Tasman and a strong S swell building Fri.

EC maintains the low as a weak, amorphous, slow moving  system North-East of Tasmania with no major swell being produced as it lingers in the Tasman.

Model divergence in these periods of troughiness is par for the course so check back in Fri and w’ll have a clearer idea of how next week will shape up as well as a last look at the weekend.