Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Mon 19th Dec)

Forecast Summary (tl;dr)

• Renewal of strong S/SE swell on Mon with continuing S'ly winds
• Plenty of SSE-SE swell Tues, easing through the day with S’ly winds moderating
• Gradual easing of swell and wind for the rest of the week
• Developing N/NE winds Thurs with minor NE windswell in the a’noon, persisting Fri AM
• Small, weak surf Xmas weekend suitable for kids/beginners/foamies, with light S to ESE winds
• Small, weak surf extends into early/mid next week
• Possible E swell from later next week, stay tuned for updates
• Monitoring the tropics as MJO fires up monsoon trough

Recap

A strong, slow moving Tasman low has maintained a stack of S swell over the weekend, with Sat seeing the biggest size, in the 6ft+ ( a few bigger 8ft sets reported) range. Sunday backed down a notch into the 4-6ft range. Conditions were best early with lighter inshore winds which tended mod/fresh S’ly during the day. S to SSE winds have increased today with raggedy conditions across most of the region and a rebuild in SSE-SE swell continuing in the 5-6ft range. Not bad for December. We’ll see an easing trend kick in this week with a slow and steady slide downwards into the Xmas weekend. Read on for details. 

Plenty of size at protected locations Sat

This week (Dec 19-23)

The combination of a Tasman low and strong high moving through the Bight has supplied a stack of S swell to the f/cast region since late last week, with an intensification and N’ward movement of the low upping the size and local winds through today. Pressure gradients will now slowly ease as the low starts to dissipate and the strong high weakens as it moves South of Tasmania through tomorrow. As this swell generating pattern breaks down we’ll be left with a weak, troughy pattern coming into the Xmas weekend with no major swell sources on hand, so you’ll need to get your grovel boards ready for Santa.

In the short run, tomorrow is the last day of strong S-SSE swell and mod/fresh S’ly winds. In all honesty, it looks like a carbon copy of today with just a brief window of lighter S to SSW winds inshore early before winds kick up again into the 15-20kt range. Expect size to ease a notch into the 4-5ft range, and slowly roll off further through the a’noon. We may see winds lay down late in the a’noon but there’ll be plenty of lump and bump on it after days of fresh S’lies.

Pressure gradients slacken further on Wed as a weak high cell moves NE into the Tasman. Wind models are still suggesting S’lies though the morning but odds are firming for a window of land breezes early, before winds clock around light E to E/NE through the a’noon. We’ll see an easing trend all day with biggest surf early coming in at 3-4ft across a wide range of exposures, dropping down to 2-3ft through the a’noon. Winds should be light enough for all day surfing with the sea state calming down from the hectic S’lies we’ve been experiencing.

N’lies kick in Thurs as an elongated high cell sits off the sub-tropical NSW coast. They’ll start off light, getting up to 20kts during the a’noon, with some minor NE windswell in the mix by close of play. Through the morning, it’ll be mopping up what is left of the SE swell with some early 2-3ft sets, easing right back during the a’noon. That will be the last of it.

By Friday we’ll be in grovel mode. Small amounts of NE windswell will be in the mix through the morning - less than 2ft- and early N’lies may tend NW, or even W/NW as a trough approaches. That trough may bring a late S’ly change will no major swell increase. We’ll finesse the timing through the week, but it’s not worth working around, at this stage.

This weekend (Dec 24-25)

Nothing much to work with this weekend with all points of the swell window looking very inactive.

Fridays late S’ly change extends into Sat morning before winds tend light SE through the day. No real surf is expected with size in the 1-1.5ft range. There is a faint possibility todays Tasman low may linger near the North Island Thurs and briefly aim a fetch of SE-ESE winds back towards NSW, which would see some 2ft sets Sat. Recent model runs are less and less bullish on this outcome, so we’ll just flag it now as a low odds event and see how it looks on Wed. 

Xmas day is almost certainly going to be tiny- a small mix of background E swell and ESE swell from whatever is leftover from Sat. We’ll peg it at around a foot, just surfable on foamies and suitable for beginners/kids. Light S to SE winds should tend to E’ly breezes in the a’noon in a weak synoptic environment. TL:DR- you can hit the Xmas lunch and enjoy a post lunch nap with no concern for missing any surf for the arvo session. 

Next week (Dec 26 onwards)

Keep the foamies/logs handy for next week- you’re gunna need them as small/weak surf persists at least into the middle of next week. 

Expect a summer doldrums pattern to persist from Boxing Day into mid next week with light winds and tiny surf.

No great details required, we’re looking at surf in the 1ft range and light E’ly breezes, with morning land breezes likely as high pressure sits in the Tasman.

From mid next week we’ll be looking to the E. 

There are a few things we’ll be monitoring. A trough of low pressure does form near the North Island. EC intensifies this but positions it right on the edge of the swell window with respect to the North Island block. A developing tradewind flow through this time is likely to favour sub-tropical areas but may spread down to temperate NSW by next weekend.

GFS suggests the system near the North Island will retrograde back into the Tasman Sea later next week, offering up good potential for a fun sized E swell over the New Years weekend. Stay tuned for details there.

In the background the tropics are looking active as the MJO signal fires up the monsoon trough and a strong cross-equatorial flow through PNG and the Solomons enhances the chances of tropical depressions forming. There’s nothing specific to mention today but chances are by Wed we’ll have something more concrete to talk about for the first week of the New Year.

Check back Wed and we’ll see how it’s shaping up.