Small surf continues but watching the South Pacific for potential TC intrusion into the Coral Sea

Steve Shearer picture
Steve Shearer (freeride76)

South-east Queensland and Northern NSW Surf Forecast by Steve Shearer (issued Fri 1st Dec)

Features of the Forecast (tl;dr)

  • Small weak surf extending into the weekend with light winds 
  • Small S-S/SE swell Mon/Tues with S-SE winds
  • Tracking potential tropical depression or TC near Solomon Is later next week, odds firming on a cyclone swell as it enters Coral Sea- check back Mon for revisions
  • Building E’ly tradewind swells at a minimum likely into next weekend

Recap

Small and clean yesterday with a hot W/NW-NW flow before N'ly breezes and size in the 2ft range. Similar winds today with the MNC picking up a small signal of SE swell from a low off the South Coast and the rest of the region seeing small NE swells to 1-2ft.

MNC picking up a little more size than the rest of the region with clean morning conditions

This weekend (Dec 2-3)

Few tweaks the weekend f/cast, mostly in terms of local winds. Low pressure has moved off the Far South coast and is slow moving, with a broad fetch of strong E’ly winds on the southern flank of the low supplying some small 2ft SE swell to the MNC. Elsewhere we’re looking at small, weak NE swells to 1-2ft or less. A lingering trough off the MNC is maintaining a hot NW flow through the region with clean conditions for Sat morning before winds tend N/NE in the a’noon.

Light offshore winds again for Sun morning before a variable SE/NE flow as the trough stalls out and dissipates across the region. Not much surf expected with a very small weak signal from the NE in the 1-1.5ft range. 

Next week (Dec 4 onwards)

Looks like a small troughy area advancing up the NSW Coast early next will steer a S-SE flow through the f/cast region, possibly light early and tending to mod/fresh SE’lies during the day. We’ll see some small S and S/SE swells, from a parent front/low which traversed the lower Tasman on the weekend and more local onshore winds. Not much to it- 2-3ft at S facing beaches and with the onshore flow keep expectations low.

Weak high pressure moving NE into the Tasman brings light land and SE seabreezes Tues, tending more E-E/NE on the MNC. Not much surf expected, just some small weak windswell, possibly tending to NE windswell in the a’noon. Nothing more than 1-2ft under current modelling.

A trough mid week brings a weak S’ly change late Wed on the MNC before stalling with potential for a small, clean morning before the change and small weak surf to 1-2ft. Again, nothing to get excited about.

Further ahead and some weather model runs are starting to look pretty damn juicy with respect to a developing TC in the South Pacific moving into the Coral Sea later next week. Still very early days but a full blown cyclone swell is now a definite possibility, possibly as early as next weekend and into the week 9/12 - initially very much favouring QLD and NENSW.

A more bog standard E-E/NE trade-swell also looks highly likely later next week and into the weekend as high pressure and the southwards moving depression/TC combine. 

Obviously, expect revision, possibly major when we come back on Mon. 

Until then, have a great weekend!

Comments

donweather's picture
donweather's picture
donweather Friday, 1 Dec 2023 at 7:13pm

Eerily good agreement between latest GFS and EC runs too.

freeride76's picture
freeride76's picture
freeride76 Saturday, 2 Dec 2023 at 5:42am

Juicy/scary prospects on charts this morning.
We could have a Cat 3 or above TC in the Coral Sea next week.

tip-top1's picture
tip-top1's picture
tip-top1 Saturday, 2 Dec 2023 at 6:46am

looks like it might get up close and personal if all comes together

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Saturday, 2 Dec 2023 at 8:20am

Fingers crossed GFS wins the long game and it stays out to sea.
EC this morning not looking good for surfers or CQlders.

Fresh55's picture
Fresh55's picture
Fresh55 Saturday, 2 Dec 2023 at 11:05am

Maybe stupid question.

But does warmer sea temps coming down further south mean cyclones would travel further south than normal or this isn’t a factor ?

Island Bay's picture
Island Bay's picture
Island Bay Saturday, 2 Dec 2023 at 12:21pm

Yes, it means that it's likely to maintain its tropical warm core structure for longer.

And here's the 18Z GFS run. Getting close!

tip-top1's picture
tip-top1's picture
tip-top1 Saturday, 2 Dec 2023 at 1:09pm

heres hoping it stays east !!
whats the lowest hectapascle a cyclone has got in our waters or neighbouring ??

donweather's picture
donweather's picture
donweather Saturday, 2 Dec 2023 at 3:11pm

I’m still leaning towards her getting whisked away to the SE.

Island Bay's picture
Island Bay's picture
Island Bay Saturday, 2 Dec 2023 at 3:57pm

Or possibly stalling in the Coral Sea. It's a good ridge to the south.

EC is the better model on average, but after 29 years of forecasting, I have a soft spot for GFS when it comes to TCs.

davo3000's picture
davo3000's picture
davo3000 Saturday, 2 Dec 2023 at 6:05pm

Yep what I said. Mad waves are possible.

fruitsalad's picture
fruitsalad's picture
fruitsalad Saturday, 2 Dec 2023 at 10:09pm

That local wind prediction tho...

Island Bay's picture
Island Bay's picture
Island Bay Sunday, 3 Dec 2023 at 4:28am

Latest GFS run, 12Z 02/12. Starting to look scary.

And 06Z GFS ensemble tracks, for the keen:
https://www.tropicaltidbits.com/storminfo/92P_gefs_latest.png

freeride76's picture
freeride76's picture
freeride76 Sunday, 3 Dec 2023 at 7:13am

A coast hugger or crossing would be devastating.

Island Bay's picture
Island Bay's picture
Island Bay Sunday, 3 Dec 2023 at 7:45am

Latest EC similar, but crucially has centre staying out to sea. Fingers crossed for you guys; parts of NZ (Hawkes Bay) still a wasteland after TC Gabrielle.

https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=swpa...

Craig's picture
Craig's picture
Craig Sunday, 3 Dec 2023 at 8:07am

EC's tropical storm outlook.

burleigh's picture
burleigh's picture
burleigh Sunday, 3 Dec 2023 at 11:18am

geez it's not looking great

donweather's picture
donweather's picture
donweather Sunday, 3 Dec 2023 at 12:42pm

Ok the shits not looking good ATM.

freeride76's picture
freeride76's picture
freeride76 Sunday, 3 Dec 2023 at 1:14pm

B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 92P) PREVIOUSLY LOCATED NEAR
8.9S 168.8E IS NOW LOCATED NEAR 8.9S 168.0E, APPROXIMATELY 476 NM EAST
OF HONIARA, GUADALCANAL. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND
A 020205Z AMSR2 89 GHZ MICROWAVE IMAGE DEPICT A BROAD AND WEAKLY
DEFINED LOW-LEVEL CIRCULATION (LLC) WITH SCATTERED DEEP CONVECTION
ALONG THE NORTHERN PERIPHERY. ENVIRONMENTAL ANALYSIS INDICATES THAT
92P IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH ROBUST OUTFLOW
ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA
SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 92P
WILL TRACK WESTWARD TOWARD THE SOLOMON ISLANDS AND CONTINUE TO DEVELOP
OVER THE NEXT 48 HOURS BEFORE MAKING A POLEWARD TURN AT AROUND TAU 96.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN
THE NEXT 24 HOURS REMAINS MEDIUM.

Island Bay's picture
Island Bay's picture
Island Bay Sunday, 3 Dec 2023 at 5:19pm

Latest GFS run (00Z), looking much less ominous.

eat-your-vegies's picture
eat-your-vegies's picture
eat-your-vegies Sunday, 3 Dec 2023 at 9:59pm

Hope your right bud.
What I’m seeing 10 days out is scaring the shit out of me.
Last day or so of tropicaltidbits run, which I thought was GFS has it swinging into the nth coast nsw.
I’m no weather guru at all so I rely on you guys that can decipher the modern internet stuff.
Like I said mate
Hope your right.

eat-your-vegies's picture
eat-your-vegies's picture
eat-your-vegies Sunday, 3 Dec 2023 at 10:46pm

I take it back.
I just got a better version of gfs and it has it brushing the coast.
Still,
Don’t want any floods on the nth coast.

scrotina's picture
scrotina's picture
scrotina Sunday, 3 Dec 2023 at 6:18pm

if it comes too close to the coast, is the problem that it will destroy all the banks? sorry for the ignorance, never got round to learning how to read weather systems etc. i just see a TC and get frothed for north facing stretches of coast.

SDW's picture
SDW's picture
SDW Sunday, 3 Dec 2023 at 9:05pm

Well, in relation to surfing yes, if it's too close to the coast it will just be a big blustery mess. Locations south of the cyclones centre will also experience significant storm surges, leading to extensive beach erosion, so that'll further ruin surf banks.
I think the comments on here are more concerned about the associated damage to land close to the coast if it were to make landfall.

scrotina's picture
scrotina's picture
scrotina Monday, 4 Dec 2023 at 12:55am

ah ok thanks, didnt realise it was that strong

Island Bay's picture
Island Bay's picture
Island Bay Monday, 4 Dec 2023 at 5:01am

Back to hugging the coast, sorry.
Following the possible development and movement of a TC is a good exercise in humility.

https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=swpac&...

tip-top1's picture
tip-top1's picture
tip-top1 Monday, 4 Dec 2023 at 5:58am

holy,
given we are in that first transition year back to el nino, what have previous cyclones done in this same time period,
also whats the lowest one of these storms has ever gotten down too?

SDW's picture
SDW's picture
SDW Monday, 4 Dec 2023 at 7:27am

That would be a rather remarkable weather event were it to come off like that.

AndyM's picture
AndyM's picture
AndyM Monday, 4 Dec 2023 at 9:00am

Wow, wouldn't a path like that be a lump of coal in the stocking.

simba's picture
simba's picture
simba Monday, 4 Dec 2023 at 5:41am

if it follows that trajectory they have atm then it wont be a merry xmas for a lot of people.....

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Monday, 4 Dec 2023 at 6:22am

I’m Barracking for EC now, fickle fan.

donweather's picture
donweather's picture
donweather Monday, 4 Dec 2023 at 8:38am

Yeah latest GFS is deadly.

Le_Reynard's picture
Le_Reynard's picture
Le_Reynard Monday, 4 Dec 2023 at 9:20am

Specific-path model runs a week out are pretty useless IMO. There'll be a southerly-track TC in the Coral Sea but that's about all to bank on

Craig's picture
Craig's picture
Craig Monday, 4 Dec 2023 at 9:21am

Indeed.

Island Bay's picture
Island Bay's picture
Island Bay Monday, 4 Dec 2023 at 11:14am

Nobody would stake a claim on one model run (say GFS at 00Z on day xx/yy) a week out, but when you keep following model runs and comparing different models, you get a better understanding of where the battle lines are, so to speak. Is the blocking ridge of high pressure strengthening or weakening? Is there a sharp upper trough coming in from the west which may pick up the system and steer it eastwards? Etc etc.

Combined with the use of ensemble models you will not only increase you forecast skill but also your understanding of system and synoptic features.

Le_Reynard's picture
Le_Reynard's picture
Le_Reynard Monday, 4 Dec 2023 at 3:41pm

True... useless was maybe not the correct term... mitigated-utility? I'm just dreading a news.com.au doom-article for a "2000km cyclone" or something based on far-off model runs. Maybe Swellnet could run a betting service? Odds based on models. Coast-hugger/Crossing/No-crossing??

Craig's picture
Craig's picture
Craig Monday, 4 Dec 2023 at 3:51pm

I can see it coming as well (news hype) if the models keep sniffing further south.

Craig's picture
Craig's picture
Craig Monday, 4 Dec 2023 at 9:20am

EC's latest thoughts..

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Monday, 4 Dec 2023 at 9:55am

interesting that their probability map indicates that their forecast is probably wrong.

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Monday, 4 Dec 2023 at 10:07am

or I'm wrong.. but I would have thought that for the 2 to align, the green blob should be dead centre over the position of the low on 13th Dec in the synoptic forecast.

donweather's picture
donweather's picture
donweather Monday, 4 Dec 2023 at 10:40am

It’s based on the ensemble forecasts not just the current EC model run I believe.

“The maps show the strike probability based on the number of ENS members that predict a tropical cyclone, and each member has equal weight. The strike probability is the probability that a tropical cyclone will pass within a 300 km radius from a given location and within a time window of 48 hours. ”

https://en.wikipedia.org/wiki/Ensemble_forecasting

Scroll down in this link.

More detail here
https://windy.app/blog/ecmwf-ens-weather-forecast-model.html

Island Bay's picture
Island Bay's picture
Island Bay Monday, 4 Dec 2023 at 10:41am

Yep, ensemble forecast vs deterministic.

dawnperiscope's picture
dawnperiscope's picture
dawnperiscope Monday, 4 Dec 2023 at 12:06pm

Thanks gents

fcalmon's picture
fcalmon's picture
fcalmon Monday, 4 Dec 2023 at 9:37am

Hi Craig,

Where did you get that screenshot from?

Craig's picture
Craig's picture
Craig Monday, 4 Dec 2023 at 9:55am
fcalmon's picture
fcalmon's picture
fcalmon Monday, 4 Dec 2023 at 10:30am

Thanks mate !

JodyP's picture
JodyP's picture
JodyP Monday, 4 Dec 2023 at 1:01pm

New moon tides next week. Sunny Coast is showing the tide range maxing itself out at around that 2m mark from Wednesday 13th to Saturday 16th, so likely through the peak of the swell and wind. Throw in some storm surge, and a likely a bunch of N and NE in the swell, and beach erosion could be significant. Hey Craig, which weather model does Swellnet use for its online long-term synoptics and forecasts?

Craig's picture
Craig's picture
Craig Monday, 4 Dec 2023 at 1:07pm

That'd be GFS.

eat-your-vegies's picture
eat-your-vegies's picture
eat-your-vegies Monday, 4 Dec 2023 at 3:21pm

Oh no!

Lol