Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon August 12th)

Features of the Forecast (tl;dr)

• Summer style E/NE swells from Tues-Thurs as broad E’ly flow establishes in Coral Sea and extends into Northern Tasman
• Some small long range E swell in the mix Tues/Wed
• NW winds for the early, tending N’ly Tues/Wed
• SW winds for Thurs AM, tending S’ly during the day
• Easing E/NE-NE swells for Fri with light winds
• Uncertain outlook for weekend as trough deepens in Tasman- Sat likely small and clean though
• Building S/SE-SE swells for Sun with SW-S winds
• Sizey S/SE-SE swells for Mon
• Still some model variance for next week, leading to low confidence - check back Wed for latest revisions
• Quiet outlook from mid next week with blocking high in Tasman

Recap

Nothing major over the weekend but a few small waves provided some fun. Sat saw surf from the S/SE with 2ft sets- a few 3 footers at better magnets- with light winds and clean conditions. Smaller on Sun, more in the 1-2ft range light variable breezes which tended E’ly in the a’noon. More small surf surf today with the occ. set from the E in the 2ft range and light morning land breezes which will tend NE as the day progresses. 

Pretty quiet but the odd set from the E was worth waiting for

This week (Aug12-16)

You would not think it was August after looking at the synoptic charts. We have a strong (1033hPa) high in the Tasman, with a deep E’ly flow through the Coral Sea feeding into a coastal trough along the QLD coast. That trough is drawing down plenty of tropical moisture in the deep onshore flow, and generating sizey, stormy E’ly swells for the sub-tropics. Some of that swell energy will filter down to temperate NSW in reduced form but without all the bad weather, along with more local NE swells. We should get a favourable wind change later this week. Further ahead and weather models have really been struggling to resolve the remnants of the troughy pattern in the Tasman over the weekend. It does look like some sort of re-strengthening will occur with a S-SE flow generating swells from that direction in the medium term, although plenty of revision is likely as we move through the week.

In the short run we’ll that N’ly flow strengthen through tomorrow with a morning NW flow swinging N/NW then N-NE before veering back N’ly later in the day at mod paces. We’ll E/NE swells filtering down from the southern edge of the sub-tropical fetch through the day. Nothing major but there should be fun 2 occ. 3ft waves on offer by close of play. Some small, inconsistent longer period E swell in the mix too, but only offering an occ. 2ft set and persisting into Wed.

Similar for Wed morning with E/NE swell to 2-3ft (should be a tad more consistent) bolstered by more local NE swell to similar size. N’ly winds again with a brief window of NW breezes early. A trough is pushing up the coast and we may see a late wind shift to the NW, although there is model variance there and it’s a low percentage play at this point. 

Thursday looks a better bet for a wind change with the trough bringing a light morning W-SW flow before winds swing S-SE at light paces. E/NE and NE swells at similar sizes although we should see some slightly bigger sets (3ft+) as wavelength draws out a notch. Nothing that will require a bigger board. You might need to find some wind protection from S’ly winds but swell direction will be favourable to those spots so we should see plenty of fun waves on Thurs. 

Easing swells Fri and variable winds as the trough moves offshore and a weak, troughy pattern sits over Central NSW. We should see mostly 2ft surf with the occ. 3 footer dropping back to inconsistent 2ft through the day. 

This weekend (Aug 17-18)

Tricky weekend outlook as a trough looks to reform and deepen in the Tasman Sea, so expect revisions as we move through the week. Reasonable confidence Sat will be small and weak- 1-2ft tops-with a variable offshore flow. 

Sunday looks a different story. With the trough deepening as it tracks towards New Zealand, we should see a S/SE-SE fetch develop through the central/southern Tasman later Sat into Sun (under current modelling). That should produce a fairly steep increase in S/SE-SE swell through Sun, likely pushing up from 2-3ft into the 4-5ft range through the day. We’ll pencil these numbers in and expect revisions through the week. Winds look to clock around from SW to S through the day.

Next week (Aug 19 onwards)

Lots of model divergence surrounding the trough of low pressure in the Tasman early next week.

At a minimum, we should see solid S/SE-SE swells for Mon with light SW-SE winds, so pencil that day in.

EC is suggesting an intensification of the fetch out of Cook Strait through Sun/Mon which would generate a nice pulse of SE-E/SE swell laster Tues into Wed, if it comes off.

The GFS resolution favours a weaker system, which washes out and rotates out of the swell window quickly, suggesting a fairly rapid drop off in size through Tues and into Wed.

Longer term both major models suggest a quieter period from mid next week with blocking high pressure in the Tasman and not much action from the south. That will likely see weak NE wind swells come into play. Way too early to have any confidence in that outlook with the Tasman Sea in a troughy mood. 

Check back Wed for the latest update.