Complex trough and potential low off North Coast this week brings plenty of swell and tricky winds

Steve Shearer picture
Steve Shearer (freeride76)

South-east Queensland and Northern NSW Surf Forecast by Steve Shearer (issued Mon 19th May)

Features of the Forecast (tl;dr)

  • Very complex outlook as low pressure trough deepens off MNC coast this week, potentially with multiple low centres within
  • Building swells Tues, staying elevated Wed
  • Likely SW-S winds for most of the region, possible W-W/SW near trough line or small low centres- keep tabs on local winds!
  • Easing but still sizey Thurs with tricky winds- likely offshore for most of region
  • Size and winds dependent on movement of trough/low- E swells stay sizey into Fri and the weekend but low confidence on specifics
  • More E swell next week, this time longer range
  • Potential for sizey S swells next week as front/low push into Tasman
  • Very dynamic situation, stay tuned for updates and revisions!

Recap

Saturday offered up some small, fun E swell in the 3ft range with clean conditions under light winds.  Smaller swells from the E on Sun but a strong signal of S swell pushed across NENSW in the a’noon with sets topping out at 4ft+ at S exposed breaks, under mod SW-S winds. That swell has eased back across NENSW, still showing some 2-3ft size across SEQLD S facing beaches with a new signal of S swell now building across NENSW as a trough deepens off the Mid North Coast. Mod/fresh S’ly winds are developing across most of the region, although there are pockets of more W/SW-SW wind around the trough line between Yamba and Coffs.

Another flood plume out of the Tweed with bluewater and fun S swells in close

This week (May 19-23)

A very unstable, dynamic synoptic chart this week with a large high (1034hPa) moving from the Bight through Victoria, with a coastal trough deepening on the leading edge of the high directing very moist onshore winds across Central NSW, extending up into the sub-tropics. We still have some model uncertainty over the fate of this trough. Fridays forecast of a low or ECL variant was downgraded into a persistent trough over the weekend but there are still model runs suggesting a low or (more likely) multiple embedded lows will form in the trough line this week. These small lows may move north, then east and finally south or may coalesce in a more classic Tasman Low or ECL variant. With so much uncertainty still around be prepared for major revisions as we move through the week. This is a nightmare to forecast!

In the short run the trough is likely to deepen and angle NE-SW with a position around Coffs. Areas around or north of the trough line see W-SW winds, SE to the south of the line. Further north a more general SW-S’ly flow is expected. Keep tabs on local winds if you can- with so much instability around we may see wind reversals around small, local circulations. Building swells are expected with size expected to trend upwards from 4ft into the 5-6ft range, likely bigger on the MNC and grading smaller the further north you go into QLD. Expect big intra-regional differences in surf size and quality!

Plenty of size Wed, thats about the only thing we can have confidence in. E/SE’ly swells to 5-6ft with bigger sets on the North Coast to MNC are on the menu. As far as local winds go- confidence is extremely low. EC is the only model suggesting the trough or low remains off the MNC with similar winds to Tues. GFS and ACCESS move the trough/low northwards (potentially pushing a small low centre onshore) which would bring widespread onshore SE-E winds across NENSW up to the Gold Coast, with a SW-S flow on the Sunshine Coast. Keep tabs on local winds and below the line commentary as we update in real time. Lots of potential outcomes are on the table, including really good, offshore surf. 

Forecast confidence remains low as we move into Thursday. Lots of outcomes still on the table.  The trough off the MNC-North Coast may deepen into a low and track southwards as suggested by EC and ACCESS. Or the whole pattern may just wash out  into a generalised onshore flow with easing swells (GFS resolution). We’ll still see plenty of size though with E’ly swells at least 4-6ft, bigger on the MNC. Stay tuned and we’ll try and update below the line before Wed’s notes. 

Similar low confidence for Fri as model divergence widens over the fate of the trough/low in the Tasman. European model and ACCESS favour the low to move southwards with offshore winds through Fri. GFS is less bullish with easing but still onshore winds and smaller swells from the E.

This weekend (May24-25)

Same very low confidence applies to the  weekend f/cast, so take current wave model output with a grain of salt. About the only thing we can be sure of is swell will be from the E through E/NE. Either solid from a low moving southwards through the Tasman or more modest from an E’ly fetch off the top of the high. For the sake of it, we’ll pencil in 3-5ft and adjust up or down as we get more clarity though the week. 

Winds are likely to tend N’ly through NW’ly over the weekend as a major low-pressure approaches from the west. 

Next week (May 26 onwards)

A broad E’ly fetch developing through the South Pacific will provide more E’ly swell into next week with improving quality as wavelength draws out.

That’s likely to be overshadowed in NENSW by strong S swells as a front and parent low moves aggressively into the Tasman early next week (see below). 

 

Too early to have confidence in size or timing but early indications are looking like it will be significant S swell event, likely developing late Tues/Wed. 

Lot’s of short em uncertainty to get through before then so check back Wed and keep tabs on below the line comments as we track this dynamic Tasman Sea weather event. 

Seeya Wed!

Comments

swellsam's picture
swellsam's picture
swellsam Monday, 19 May 2025 at 3:50pm

At what point in time will we start to have some confidence in winds? Hoping by Wed PM? i've got the calendar free thurs and fri for a strike mission down south. The forecast keeps going back and forth playing with my emotions!

freeride76's picture
freeride76's picture
freeride76 Monday, 19 May 2025 at 3:53pm

Definitely by Wed.

Ripper's picture
Ripper's picture
Ripper Monday, 19 May 2025 at 5:49pm

Total wipeout today! Large swell with heavy cross/onshores & pouring rain all day! Forecast for the nxt few days looking grim here on the Mid Nth Coast!

freeride76's picture
freeride76's picture
freeride76 Monday, 19 May 2025 at 6:15pm

Interesting arvo here.
wind stayed offshore.

Swell pulsed but it was super weird.

I saw one massive 5-6ft set that broke way out on the wide storm bank, then nothing,

3-4ft the rest of the time.

AndyM's picture
AndyM's picture
AndyM Monday, 19 May 2025 at 6:21pm

Went for a surf just before dark.
Beautiful clean surface conditions, some nice waves though the sand is still very ordinary.
3-4 ft and yes, got caught inside by a set that capped out on the pinnacle and looked 5ft+.
That set was a one off, saw nothing like it again.
Edit: felt slightly sharky.

freeride76's picture
freeride76's picture
freeride76 Monday, 19 May 2025 at 6:22pm

Looks like the trough line will oscillate between Port and Yamba/Ballina over the next 36-48hrs.

Still a fair bit of model divergence over the exact timing and placement of that trough line and any low that forms in it.

adsi's picture
adsi's picture
adsi Monday, 19 May 2025 at 6:37pm

Heirgo we should have reasonable surface conditions all week then I'm guessing. Might take half day off Thurs!
Hopefully find something tomorrow morn too.
Cheers for the write up as always !

Pngy's picture
Pngy's picture
Pngy Tuesday, 20 May 2025 at 8:38am

Any new updates on how this will play out over the next couple of days?

Distracted's picture
Distracted's picture
Distracted Monday, 19 May 2025 at 9:20pm

Crazy how localised these low pressure cells can be in the coastal trough. Today it tracked up the coast from Newy to Port Macquarie, dropped a gut full over Port and now it’s headed back down the coast and is dumping over Forster.

freeride76's picture
freeride76's picture
freeride76 Tuesday, 20 May 2025 at 7:48am

Sunshine, offshore winds and 4ft of swell here this morning.

Can't see your feet and the sand is still AWOL but I'll take it.

juegasiempre's picture
juegasiempre's picture
juegasiempre Tuesday, 20 May 2025 at 7:56am

It feels like over the last few years I've lived through 5 lifetimes of 1 in a 100 year weather events relating to rain. Which is crazy enough but then I remember years of drought before that and a big arse bushfire!

Wtf is going on?!

TH's picture
TH's picture
TH Tuesday, 20 May 2025 at 8:00am

Wet and wild here at Cresso Head this morning, Waiting for the alert we've been flooded in.

adsi's picture
adsi's picture
adsi Wednesday, 21 May 2025 at 8:45am

Funny swell this morn, no where really looking much good. Im guessing its because the swell has been generated close to the coast so its a bit disorganised ?

thermalben's picture
thermalben's picture
thermalben Wednesday, 21 May 2025 at 8:45am

5-6ft sets on the Tweed, clean with offshore winds but didn't really see anywhere handling it.

tiger's picture
tiger's picture
tiger Wednesday, 21 May 2025 at 9:25am

Major flooding happening on the MNC, with plenty more rain to come. Looking like good waves on the other side of it, but with the Macleay, Nambucca, and Bellinger all in major flood, water quality is going to be diabolical.

freeride76's picture
freeride76's picture
freeride76 Wednesday, 21 May 2025 at 2:41pm

BOM has forecast showers yesterday and rain today but so far it's held off- I can see with the naked eye the line of bad weather to the south and south-east which marks the edge of the trough-line.

Pumping 5-6ft surf today but banks remain diabolically bad so a day that would be an 8-9/10 is a 4 or 5.

Talking to lots of local crew who are talking about taking up pickle ball. It's getting that grim having our world class points off line for so long.
Or moving to uxxxxxxxa

Sprout's picture
Sprout's picture
Sprout Wednesday, 21 May 2025 at 3:46pm

I've been moving there for 10 years now.

swellsam's picture
swellsam's picture
swellsam Wednesday, 21 May 2025 at 2:52pm

I'm still seeing lots of differences in tmrs wind forecast. In the yamba region, swellnets forecasting moderate northerlies all day, surfline and willyweather have it light westerlies in the AM into moderate southerlies in the PM. Keen to have a good read of today's forecaster notes.

thermalben's picture
thermalben's picture
thermalben Wednesday, 21 May 2025 at 2:59pm

Our new, upgraded model (coming very soon! See below) has light W'lies at the coast for tomorrow.

Though to be fair, the current model has wind speeds of 9kts at 6am dropping to 4-5kts through the day. Which is essentially light and variable (no matter what the arrows are showing).

swellsam's picture
swellsam's picture
swellsam Wednesday, 21 May 2025 at 3:04pm

Thanks a lot Ben. Definitely looks like some nice conditions a head of us.

AndyM's picture
AndyM's picture
AndyM Wednesday, 21 May 2025 at 3:44pm

Looked very full and ordinary a few hours ago.
Glad I went for a surf yesterday late arvo, there were some fun waves in the 4-6ft+ range.

brevil's picture
brevil's picture
brevil Wednesday, 21 May 2025 at 4:07pm

fun dawny, great week ...more please