Tons of action ahead as Easterly Trough low forms off Sydney tomorrow

Steve Shearer picture
Steve Shearer (freeride76)

Sydney Hunter Illawarra Surf Forecast by Steve Shearer (issued Fri 1st July)

Forecast Summary (tl;dr)

  • Range of wind conditions over the weekend depending on exact position of developing low
  • Most likely best from Central Coast to Hunter, onshore from Sydney south
  • Small S swell groundswell Sat, easing Sun
  • Short range E-E/SE swell Sat, becoming large and stormy Sun PM
  • Large E/SE swell Mon with onshore winds for most of the region (possible variable/offshore on the Hunter, depending on trough)
  • Easing E/SE swell Tues, with rebuild in large S/SE swell and strong S/SE winds
  • Plenty of SE winds and swell Wed, slowly easing Thurs/Fri
  • Strong E/SE groundswell likely next weekend with good winds
  • Potential for more strong swell following week, stay tuned for updates


No great surf to speak of since the last f/cast. Yesterday saw a declining signal of SSE swell, topping out around 2-3ft own the Hunter, smaller 2ft elsewhere and clean early before SSE winds kicked in. Today is similar with a small, sloppy signal of S to SSE swell in the 2ft range and S’ly winds now kicking in as we enter into a dynamic coastal weather event.

Rain and gurgle for most of the region Friday

This weekend (July 2-3)

OK, here we go. We are starting to get some model agreement on a developing easterly trough low expected to form off the Sydney/Hunter coast through tomorrow. There’s still a degree of uncertainty as to the exact position of the low axis, which will make wind f/casts a bit rubbery and really, coming down to a game of kilometres. 

Let’s look at what we know. The South Coast to Illawarra and South-side Sydney looks the most likely to be in the direct onshore flow of the developing low, so expect a write-off for the weekend for these areas with onshores and rain and building short-range E’ly swells becoming very large through Sun a’noon.

Sydney north of the Harbour is the most in doubt, with a possible light and variable flow if the low axis is slightly south of Sydney (GFS scenario). Central Coast and Hunter are far more likely to have a variable, lighter offshore flow through Sat. That may extend into Sun morning (likely) before all hell breaks loose and E’ly to SE’ly strong winds to gales extend through the entire region as the low winds up and deepens.

Surf-wise there will be some longer period S’ly groundswell in the mix from a passing frontal system Thurs/Fri which will add around 3-4ft of surf to S facing beaches on the Central and Hunter coasts on Sat, easing into Sun.

Further south building short range SE-ESE surf will whip surf up into the 4f range by close of play.

Sunday sees the proximate fetch to the NSW Central and Southern Coast really increase in strength (see below). Winds increase to gale force, possibly strong gales and with proximity equaling a rapid increase in size we can expect surf through Sun, especially after lunch to become very large and stormy. Size up in the 6-10ft range is expected, with rideable locations limited to a handful of novelty spots.

Next week (July 4 onwards)

We’ll still be playing a game of Kilometres on Mon morning. The low axis is expected to be off Sydney with a trough line linked to the low hovering around the Hunter Coastline. Areas on the trough line or north will see a variable flow, becoming more offshore (W’ly) the further north you get from the trough line. That trough line may still meander further south during the day, extending variable winds into the fringes of the Sydney basin, or it may retreat inland, with winds freshening from the Southern quarter.

Most of the f/cast region is going to be under the influence of a stiff, SE-SSE flow and surf is expected to be solid and stormy.  Likely in the 8ft range early, but easing a notch or two during the day as the fetch rotates more SE through S. That will open up some protected locations during Mon. 

The low moves away through Mon, although a secondary centre may linger about the Central Coast region- stay tuned for updates over the weekend. As it does, it aims up a more SE angled fetch at the region which then tracks in a NNE direction through the day. This should see a renewal in more SE-SSE angled swell through Tues. Plenty of wind from the same direction through the day, keep expectations pegged. Size should rebuild from 3-5ft during the morning up into the 8ft range, bigger on the Hunter and more exposed S to SE facing stretches. Expect smaller surf at more protected locations, which will be the only places surfable under 20-30knot winds from the SSE.

By Wednesday it looks like a classic La Niña map. Strong high just SE of Tasmania with a low in the Central Tasman directing a huge windfield through most of the Central to Northern Tasman Sea. Expect plenty of SE winds and swell, likely in the 6-8ft range, easing a notch during the day.

Further into next week, and allowing for the fact the dynamism leads to low confidence this far out and it looks like the low in the Tasman moves northwards and connects with the remnants of the trough line in Coral Sea. That reinvigorates the low near the North Island, with a fetch of gales then activating off the west coast and back into the Tasman, with the low doing a slow loop de loop back south through the Tasman.

If that model scenario plays out (both GFS and EC suggest some version of it) then we will be looking at more strong swell from the E/SE to SE as the low tracks down the West Coast of New Zealand (see below). 

So expect an easing trend through Thurs/Fri, although still with plenty of size and winds from the SE-S. 

Strong new E/SE swell is then probable by next weekend 9/10 July and beyond.

Stay tuned to the comments over the weekend as the event unfolds and we can update using real-time Obs and check back Mon for a fresh and full update.

Have a great weekend!


Craig's picture
Craig's picture
Craig Friday, 1 Jul 2022 at 2:26pm

This will be a significant rainfall event with flash flooding etc.

Be prepared and take precautions. Here's the forecast for Wollongong, look at the rainfall totals forecast for the coming three days.

freeride76's picture
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freeride76 Friday, 1 Jul 2022 at 3:07pm

Jeezuz. Be careful.

MrBungle's picture
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MrBungle Friday, 1 Jul 2022 at 3:23pm

Not good. Heavy rain/flooding and big onshore surf, going to be stuck at home bored out of my mind. Hopefully next weekend and the week after that swell sticks around and the sun and good winds come back.

thermalben's picture
thermalben's picture
thermalben Saturday, 2 Jul 2022 at 6:56am

Light rain overnight from the Hunter to the Northern Beaches, moderate rainfall from the Eastern Beaches to Cronulla, and torrential rain from the 'Gong to Ulladulla.

Current totals since 9am yesty are:

Broughton Creek: 194mm
Lake Conjola: 176mm
Lake Tabourie: 174mm
Ulladulla: 165mm
Warilla: 154mm
Wollongong: 146mm
Kiama: 138mm
Greenwell Point: 130mm
Albion Park: 124mm
Jervis Bay: 119mm

sean killen's picture
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sean killen Saturday, 2 Jul 2022 at 5:23pm

Pumping waves this morning offshore 3-4ft wedges some very happy frothiers ..

thermalben's picture
thermalben's picture
thermalben Sunday, 3 Jul 2022 at 6:51am

The heaviest rainfall continues to be located south from Sydney, though it's eased up on the South Coast overnight. Notable rainfall totals since 9am y'day:

Brogers No 2 (just inland from Gerringong): 324mm - and that's on top of 229mm y'day, so 553mm in 48 hours
Wattamolla (Kangaroo Valley): 300mm
Darkes Forest (back behind Coalcliff): 278mm
Woronora Dam: 251mm
Lucas Heights: 227mm
Mount Pleasant: 219mm
Royal National Park: 215mm

thermalben's picture
thermalben's picture
thermalben Sunday, 3 Jul 2022 at 7:29am

Is this a record breaking rain event? Quite possibly for the month of July, but I'm sure about whether it creates a new daily (or 48 hour) record.

By way of an example: Bellambi's highest monthly total for July is 223mm, but we're already up to 320mm for the last 48 hours alone. So, that record has been broken.

But... Bellambi's highest monthly total for August is 682mm, in 1998 (which is def an incredible outlier, as mean monthly rainfall is only 92mm). The main source of rainfall for this month this was a low pressure trough on August 17/18, which resulted in 445mm being recorded at Mt Ousley (near Uni of Wollongong) in 24 hours.

Wyre's picture
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Wyre Sunday, 3 Jul 2022 at 11:18am

Wow Ben, interesting stats. I’m in Mount Ousley right now, and it has been intense- mount pleasant is essentially the same spot. Definitely the heaviest I’ve experienced, and a little nerve wracking having moved into a new place, finding a few leaks!!

billie's picture
billie's picture
billie Sunday, 3 Jul 2022 at 3:14pm

In your judgement, are these patterns unique since the recording of such statistics? Or just in a different month to normal?

thermalben's picture
thermalben's picture
thermalben Sunday, 3 Jul 2022 at 6:21pm

TBH, I don't know, climatology isn't my area of expertise.

Pedro1212's picture
Pedro1212's picture
Pedro1212 Monday, 4 Jul 2022 at 8:59am

I'm relishing the opportunity to hand on some climate knowledge to you guys for a change! You can get statistical design rainfall totals here and apply the lats longs of the place you are interested in:
Without knowing how many or how short the rain bursts were; 320mm in 48 hours may be a 5% annual exceedance probability rain event (or a 1-in-20 year rain event). However, if most of that rain fell over 24 hours, its closer to a 1% AEP rain event (or 1 in 100 year rain event). So 320mm in Belambi over 48 hours is rare but not extreme. The escarpment creates much more intense rain than anywhere on the South Coast. So the same rain totals at Gerringong are more rare/extreme than for the Illawarra.
Of course, these are statistical, theoretical totals and depend on a lot of extrapolation across the relatively short and patchy rainfall records that we have gathered over 220 years of European observations. Hope that helps!

thermalben's picture
thermalben's picture
thermalben Monday, 4 Jul 2022 at 12:50pm

Unreal! Thanks Pedro.

Westofthelake's picture
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Westofthelake Sunday, 3 Jul 2022 at 8:08am

A few degrees of latitude.


freeride76's picture
freeride76's picture
freeride76 Sunday, 3 Jul 2022 at 8:22am

Yep, it was even more obvious yesterday when the trough-line was about due East of Sydney Harbour.

batfink's picture
batfink's picture
batfink Sunday, 3 Jul 2022 at 7:19pm

Everyone is saying they were surprised by “how quickly it came up”.

These are people who had experience of 3 floods this year that were already record breaking.

Tough year!

batfink's picture
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batfink Sunday, 3 Jul 2022 at 8:03pm

It’s a good one Udo. Right in the firing line now. Hot water heater is giving up the ghost, I think the water is shorting it.

Will have to wait for the pissing down to cease to see if I can fix it.

eat-your-vegies's picture
eat-your-vegies's picture
eat-your-vegies Sunday, 3 Jul 2022 at 9:14pm

Looks like maybe another low will bomb you guys next weekend.
Hope I’m reading that wrong.

thermalben's picture
thermalben's picture
thermalben Monday, 4 Jul 2022 at 6:54am

I reckon the Wattamolla anemometer may be on the fritz.. there shouldn't be such a large difference between wind speeds and wind gusts.

billie's picture
billie's picture
billie Monday, 4 Jul 2022 at 10:36am

The gusts look correct, but not the spd kts

suchas's picture
suchas's picture
suchas Monday, 4 Jul 2022 at 11:05am

There is a bulk carrier adrift heading towards Wattamolla- Named Portland Bay.

MrBungle's picture
MrBungle's picture
MrBungle Monday, 4 Jul 2022 at 11:33am
Chris Buykx's picture
Chris Buykx's picture
Chris Buykx Monday, 4 Jul 2022 at 10:01am

This week will be crappy, we know that! But looking ahead from the weekend to end of next week we could be getting days of consistent swell from the SSE around to East with all day offshores - for a week. Reckon we might get a good upside on the other side of this weather event!

MrBungle's picture
MrBungle's picture
MrBungle Monday, 4 Jul 2022 at 10:55am

Yeah fingers crossed. Checked my local beach yesterday, water quality is looking terrible with the run off from the river at the end of the beach. It will need to be proper pumping to get me in that water this week.