Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 3rd Jan)

Forecast Summary (tl;dr)

• Strong E/NE swell at slightly lower levels Tues, slowly easing through the a'noon. SE winds expected lightest early, tending more E'ly during the day
• E/NE swell persists at lower levels Wed, rebuilds Thurs with fresh NE winds developing
• E/NE swell holds Fri, tending to NE windswell in the PM, with NE winds
• Easing NE swell Sat, S'ly change likely
• Small surf Sun and into early next week
• S swell possible Wed
• More tropical E/NE swell likely from Wed next week, stay tuned for details

Recap

A few fun waves surf wise over the New Year’s weekend. NE windswell ticked along in the 2-3ft range Sat, with a slight increase into the 3-4ft range Sun. Surf was heavily tidally affected. This morning has started out undersized with a slight increase in E/NE swell into the 3ft range. An increase in size from the E/NE generated by TC and now ex TC Seth is incoming and on the build. 

Swell from the E/NE on the build today, albeit a bit lumpy

This week (Jan 3-7)

Swell from ex TC Seth, which transitioned into a gale force sub-tropical low Sun is the major synoptic feature this week, responsible for both swell production and directing gradient winds as it slowly weakens and meanders close to the NENSW/SEQLD coast for the next few days. It’s not the ideal position or track for local winds in most of NSW, including the f/cast region. 

With the low expected to be at it’s most S’ly position tomorrow we should see SE winds from the further expanse of winds rotating around the southern quadrants of the low. 

Size will be down a notch from Fridays f/cast due to the more northwards positioning of the low but plenty of juice from the E/NE is still expected in the 4-6ft range through tomorrow, ramping down slightly through the a’noon. Those winds will start to tend more E’ly through the a’noon as the low begins to meander north again leaving behind a residual E’ly wind.

That E’ly wind will be a major factor Wed, with a weak high cell in the centre of the Tasman and the dissipating low combining to direct a straight E’ly flow across the region. Expect mod/fresh winds, lighter in the morning, with a small possibility of a morning land breeze north of the Harbour. There’ll still be significant E swell in the water with size in the 3-5ft range. By the a’noon winds will start to tend more NE, opening up options in northern corners. 

The latter part of the week sees NE winds really start to ramp up as a strong high drifts underneath Tasmania into the Tasman and begins to immediately tighten pressure gradients with an inland trough system laying N-S through the interior. It’s a bit more than a usual Nor-east wind, more a true gradient Nor-easter- a miniature version of 2016’s Black Nor-Easter- and it’s expected to see winds ramp up through Thurs. 

It will also generate more local E-E/NE swell Thurs, pushing wave heights back up into the 4-5ft range at exposed breaks. If you can get out of the wind there’ll be waves on offer but quality may be hard to find.

No great change to end the week. NE winds remain fresh as the slow moving high and interior trough maintain a tight pressure gradient. That will see surf hold in the 4ft range, with the E/NE swell tending to NE windswell during the a’noon. Same recipe as the previous few days, northern corners will see the cleanest conditions. 

This weekend (Jan 8 - 9)

Sat finally sees a decline in wave heights across the region as the N’ly fetch breaks down and gets shunted away by a trough which brings a S’ly change during the day. We’ll finesse the timing of that change during the week but a window of pre-frontal N or NW winds is likely with a morning peak in size of 3-4ft, before surf eases during the day. S’ly winds will confine surfing to more sheltered spots once they kick in, although a window of lighter winds around the trough line can’t be ruled out.

Sunday will be a low point in the f/cast period and to be honest looks like a lay day. Small amounts of leftover E/NE swell in the 2ft range and some short period S’ly windswell in the same size range with mod S’ly winds. If you are super keen there’ll be a wave to ride.

Next week (Jan3 onwards)

More action in the tropics next week. Later this week another tropical low is expected to form in the South Pacific- possibly between Fiji and Vanuatu. That has swell generating potential in and of itself depending on how it moves into the swell window. A long cradling fetch of E/SE Tradewinds forms in that general region, which is likely to be a more reliable swell producer, especially for more northern parts of the State and QLD. 

The weekend’s S’ly change dissipates quickly with winds tending N’ly again. A few small days are expected to start next week with small, weak windswell on offer. 

A stronger trough mid next week may see a S’ly fetch develop in the lower Tasman with a small S swell possible by Wed. By Wed we should see E/NE tradewind swell from the South Pacific source start to bump up wave heights into the 2-3ft range. 

Stronger E/NE groundswell is a good possibility into the end of next week but we’ll need more model guidance with such a long lead time leading to low confidence.

More low pressure development in both the Coral Sea and South Pacific is also being suggested by weather models. 

Check back Wed and we’ll how much of that tropical activity will extend down to temperate NSW.