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

Forecast Summary (tl;dr)

• Small surf Thurs-Fri with a N'ly pattern
• Small, NE windswell on the cards for New Years weekend, possibly muscling up later Sun
• Steep increase in muscular E/NE swell Mon, likely peaking later Mon with light NE winds
• E/NE swell at slightly lower levels Tues, slowly easing through day. Light winds early, S'ly change expected in the AM
• Local and mid period S swell likely Wed/Thurs
• Possible strong S'ly or S/SE groundswell later next week or weekend. Stay tuned for revisions on timing and size on Fri

Recap

Strong SE winds yesterday mostly made a mess of surf in the 3-4ft range through the region, with only more protected spots seeing rideable, albeit smaller waves. Today has settled down considerably, with a morning land breeze, most prominent in the Sydney Basin, offering up much cleaner conditions. Surf in the 2-3ft range offered much better options than the last few days. More exposed coasts like the Hunter were still scrappy and raw from the prevailing sea state with messy 2-3ft surf. A tropical low tracking down from the Coral Sea is the headline feature, read on for details.

Small, but clean and inviting under offshore winds and warm, blue water

This week (Dec 29-31)

A dual-centred high is ever-so-slowly tracking through the Bight, with the smaller, eastern centre now sliding into the Tasman Sea. The extremely strong high pressure surge experienced since Boxing Day has weakened as pressure gradients ease which is ushering in more settled conditions. The action in the tropics is hot and heavy with a tropical low (Invest 97S) located just south of Mornington Island in the western Gulf of Carpenteria. This low is expected to  track quickly across Cape York Peninsula, reforming in the Coral Sea within the next 24 hrs. It’s still a chance of then forming into a tropical cyclone, although it’s far more likely to remain a tropical low. Surf prospects from this low are now upgraded to excellent with major weather models expecting the system to track  parallel to the East Coast, possibly reforming as a significant extra-tropical storm in the lower Tasman Sea next week. Let’s dig in to the details. 

Not much point going into detail over the short term. Small surf will pad out the rest of 2021. A mix of small swell trains from the E/SE with a few traces of S swell, all up offering up a few 2footers Thurs morning, easing during the day. Expect cleanest conditions early before winds tend E/NE, then NE and begin to freshen.

By Friday the N’ly pattern will be more entrenched as high pressure drifts E across the Tasman. Small leftovers in the 1-2ft range early should perk up a notch in the a’noon as NE windswell starts to build. Keep expectations low; it’s short period stuff unlikely to exceed 2ft. Just enough to end the year with a surf.  Expect a little more size on the South Coast.

This weekend (Jan 1 - 2)

By New Years Day the charts will be looking insane, with a tropical low off the CQ/Fraser Coast and the QLD Points on the pump.  Central/Southern NSW will have to cool their heels for a bit longer until the low drops down into the swell window proper.

Sat will be small with NE windswell lifting a notch into the 2-3ft range, and a continuation of mod/fresh NNE to NE winds. 

Sunday is slightly more tricky to call. It’s highly likely short period NE windswell will be the dominant swell source, with surf in the 2-3ft range continuing at spots exposed to that swell direction. It’s likely surf could muscle up a notch in the a’noon as the cradling fetch of E to E/NE winds starts to send swell trains from that direction down the NSW Central Coast. The initial increase will be modest- more noticeable as a slight change in direction, with some 3ft sets on offer. EC tracks the system south slightly ahead of GFS which does offer up chances of a more significant increase on Sun a’noon. Final update in Fridays f/cast notes.

Next week (Jan3 onwards)

With the tropical low slipping southwards over the New Years weekend, Mon now has excellent prospects for a solid increase in E/NE groundswell. The cradling fetch intensifies as the low drifts south, with broad fetch of gales aimed at NSW. A core fetch of stronger storm force winds is also in the swell window aimed more directly at the northern NSW coast.

Expect size to ramp up through Mon starting off a bit undersized in the 3-4ft range, and building into a chunky 4-6ft during the day. With swell periods in the 11-13 second band and the direction “straight on” at most spots, there will be plenty of juice so choose spots according to ability and experience. Winds are a factor, starting off light and variable and tending light/mod NNE to NE during the day. Assuming they stay on or under the modelled speeds, there should be plenty of good options through the a’noon as the swell pulses.

Tues morning looks fantastic. Light land breezes should see A-grade conditions, with plenty of surf just off the peak from Mon. Size in the 4-6ft range, tending slowly more towards the E as the system tracks southwards,  should see an excellent morning of surfing. The wild card on Tues will be the timing of an expected S’ly change moving up the coast. Current modelling suggest a mid morning S’ly change through the Sydney basin. That will confine surfing to more sheltered spots once it kicks in. Those should offer up great surf as the swell direction gets straight in there. Expect size to ramp down through the day. 

The second half of next week is still a bit of a mystery bag. S swell is likely to fill in Wed, generated by the front which brought the S’ly change Tues. Expect S to SSE winds through Wed. Leftover E’ly swell energy should hold 2-3ft surf at more protected locations.

Models diverge through next week. EC suggests an extra-tropical transition with the low becoming a strong, mid-latitude storm and drifting towards New Zealand’s South Island later next week. That suggests S to SSE swell  holding into next week, with a more powerful pulse of S/SE groundswell later Fri or into the weekend. 

GFS has the system race away to the south before undergoing ETT (extra-tropical transition) and re-strengthening in the far Southern Tasman Sea mid-late next week. Latest modelling suggests a powerful, long period straight S swell from this source likely arriving next weekend.

Further tropical low pressure is expected to develop in the Coral Sea or near South Pacific in the New Caledonia area during this period, as well as a possible low pressure trough off the NSW Central Coast. Under current synoptic dynamics, these scenarios will likely be subject to serious revision. 

Looks like plenty of surf ahead though.

Check back NYE for the Final F/cast notes for 2021. Plenty of good news is expected.