Forecaster Blog: Tropical Cyclone Forming Near Vanuatu Fuels Rise in SE, ESE Swell For Southern QLD This Weekend

12 Feb 2019 5 Share

Ben Macartney

Chief Surf Forecaster

Updated Wednesday, February 13, 2019

It’s been a pretty slow start to the tropical-swell season, but at long last there’s every reason to think we’re about to enjoy a more substantial run of swell under favourable SSE winds across southern Queensland’s points this weekend.

Category one Tropical Cyclone Oma, located about 235 nautical miles northwest of Vanuatu, has emerged as the focal point of an active Monsoon trough spanning the Southwest Pacific Ocean. As discussed in my recent blog, the cyclone looms as a major driver of energetic SE to ESE swell as it interacts with a building subtropical ridge to its southwest over the next few days. Over the last 48 hours we’ve seen the various models tightening up on the projected strength and track of TC Oma leading into the end of this week, this weekend and through to early next week – and this in turn is lending increasing confidence to projected surf emanating from the system.

But just how is this event likely to stack up, compared to say, the E groundswell generated by Tropical Cyclone Winston, back in 2015? Or even TC Gita in 2018?


Tropical Cyclone Oma will very likely emerge as a strong SE swell-produce later this week. Source: Fiji Met Service.

Tropical Cyclone Oma will very likely emerge as a strong SE swell-produce later this week. Source: Fiji Met Service.

The early stages of this event commenced with the arrival of a southerly change across the Eastern Seaboard on Wednesday, leading in a strengthening sub-tropical ridge that’s projected to build over the Tasman Sea into the end of the week - in turn setting up a broadening SSE to SE fetch inside northern NSW and southern Queensland’s short-range swell window. In the first instance that means rising SSE/SE windswell for these more northern venues on Friday, characterised by a steady build in wave height and lengthening of wave period.

Latest virtual buoy readings for southern QLD are impressive.. But will it live up to the hype? Source: CW Wave Tracker

Latest virtual buoy readings for southern QLD are impressive.. But will it live up to the hype? Source: CW Wave Tracker

As TC Oma further strengthens it’s forecast to curve south and then southwest, on a trajectory that will take it directly across New Caledonia this weekend. As this occurs, a broad SE fetch will go to work across the northern Tasman and southern Coral Sea; generating a larger component of ESE swell fanning out towards the QLD/ northern NSW coast. Going on recent WW3 runs, this will culminate in larger, mid-period ESE swell building to peaks of 4 to 6ft plus across southern QLD and northern NSW coasts this weekend – perhaps even bigger as it reaches peak size later Saturday/ early Sunday.

At this early stage it’s worth keeping in mind that we could see changes to these projections in light of TC Oma’s development over the coming days – but however it pans out it now looks clear that the coming weekend will see no shortage of surf.

By early next week we should initially see a gradual easing trend in easterly swell across the region, levelling off in the vicinity of 3 to 5ft Monday/ Tuesday under moderating SE tradewinds. Beyond that, the models point to a range of scenario’s. The EC model has ex-TC Oma going extratropical as it moves poleward across the Tasman Sea from Tuesday to Friday next week. This could see a renewed push in sizeable, mid-period easterly swell setting in across the entire Eastern Seaboard – but at this stage confidence on this possibility is still at the low end of the scale.  

Latest peak wave period readings for Sunday have come down a second over the last couple of days. Source: CW Wave Tracker.

Latest peak wave period readings for Sunday have come down a second over the last couple of days. Source: CW Wave Tracker.

Sowing the Seeds of Doubt
While this all, prima facie, looks somewhere between really good and straight up epic, there are a few key reasons to view these projections with a critical eye. In the wind-graph below, we can see how the coastal fringe is only exposed to the south-western boundary of the fetch area, with the bulk of sea-state being generated by the fetch aimed further north. That points to a more directional event, quite possibly of shorter peak periods than what current runs are showing; translating into good, but far from epic conditions for the points. To further elaborate, the stronger peak periods of 10 to 11 seconds showing for Sunday are linked to sustained SE winds of 30 to 35 knots over the northern Tasman Sea on Friday through early Saturday, triggering a strong component of ESE swell spreading radially off the primary, deepwater SE swell-train.

This chart depicts sea-surface winds, showing the oblique alignment of the developing fetch in relation to the QLD/ northern NSW coast. Source: BOM.

This chart depicts sea-surface winds, showing the oblique alignment of the developing fetch in relation to the QLD/ northern NSW coast. Source: BOM.

In short, there are competing scenarios indicating the fetch won’t quite live up to these projections – and hence we may well see projected wave height and period dropping back a notch or two as the week progresses. Having said all that, the vagaries of tropical cyclone development means there’s still plenty of wiggle room for revisions to the projected swell and the timing of its arrival, so stay tuned for more on how it will play out later in the week.

TC Oma is projected to curve southward on Wednesday and Thursday, before moving directly over New Caledonia this weekend. The storm's track and intensity will be a key determinant of surf-potential for southern QLD this weekend. Source: JTWC

TC Oma is projected to curve southward on Wednesday and Thursday, before moving directly over New Caledonia this weekend. The storm's track and intensity will be a key determinant of surf-potential for southern QLD this weekend. Source: JTWC


Tags: Forecaster Blog , Ben Macartney , Tropical Cyclone Oma (create Alert from these tags)

blog comments powered by Disqus
More From Forecaster Blog
Forecaster Blog: Strengthening Tradewinds over the Southwest Pacific Sees New E Swell Inbound Next Week

Forecaster Blog: Strengthening Tradewinds over the Southwest Pacific Sees New E Swell Inbound Next Week

There's latent E swell potential brewing over the Southwest Pacific.

1 5 Feb 2019
Forecaster Blog: Large NE swell To Grace The NSW Coast And TC Owen To Follow

Forecaster Blog: Large NE swell To Grace The NSW Coast And TC Owen To Follow

Christmas comes early to the NSW coast this year.

2 11 Dec 2018
Recent

Ryan Callinan Signs With Ocean & Earth

With a short, sharp banger of a clip!

22 Feb 2019
Fun News: Kelly Slater Will Be in the Vissla Sydney Surf Pro This Year

Fun News: Kelly Slater Will Be in the Vissla Sydney Surf Pro This Year

1 20 Feb 2019
Merewether wins the 2019 nudie Australian Boardriders Battle!

Merewether wins the 2019 nudie Australian Boardriders Battle!

18 Feb 2019
Ryan Callinan, Jack Freestone, Ethan Ewing and Seth Moniz Shred Mysto Pointbreak

Ryan Callinan, Jack Freestone, Ethan Ewing and Seth Moniz Shred Mysto Pointbreak

8 Feb 2019
Mick Signs With Rip Curl For Another Ten Years

Mick Signs With Rip Curl For Another Ten Years

7 Feb 2019
Latest News

Ryan Callinan Signs With Ocean & Earth

With a short, sharp banger of a clip!

Merewether wins the 2019 nudie Australian Boardriders Battle!

Watch the highlights from an absolute belter of an event

Mick Signs With Rip Curl For Another Ten Years

That'll make it 30 all up for the 3x World Champ and Rippy

Popular This Week

Cyclone Oma Awoke Kirra From Her Slumber Thursday

The famous point break provided some solid barrels Thursday for the likes of Mick, Parko, Freestone and more.

Cyclone Oma Lights Up Noosa - Nature's Own Perfect Wave Pool

Whilst the Gold Coast was a little bigger, Noosa provided epic, perfect lines for Julian Wilson, Asher Pacey and a handful of other pros along with several hundred wave-starved punters

Snapper Turns On In Anticipation For Tropical Cyclone Oma

Mick Fanning, the Occ, Jack Freestone, Seth Moniz, Owen Wright, Vassa and many more dining out on some thick ones behind the rock at Snapper.

Byron Bay Shark Attack: There was a big chunk taken out of his leg...

Byron beaches closed after 41 year old man airlifted to hospital.

Go to Top