Strong back-to-back swells in South Oz

Ben Matson picture
Ben Matson (thermalben)

South Australian Surf Forecast by Ben Matson (issued Friday 2nd October)

Best Days: Sat/Sun/Mon: pulsey long range, long period W/SW swells with fun surf on the Mid and clean but inconsistent surf down south. Tues: strong combo of swells but with mainly onshore winds on the Mid (clean down south). Wed: potentially light cross-offshore winds on the Mid and good surf. 

Recap: Thursday remained small as expected across most of the SA coast, and winds swing onshore at Victor in the morning, rendering most beaches quite bumpy. A small new groundswell has filled into the region today, and wave heights have increased bang on as per expectations - we’re seeing smooth 2-3ft sets at Middleton (as per the images below), and even the Mid Coast has glassy 1.5ft sets across the reefs. 


Lovely glassy lines on the Mid Coast; shame it ain't 4ft bigger

This weekend (Oct 3 - 4)

No major changes to the weekend forecast. 

We’ve got a series of strong new W’ly tending W/SW swells, originating from a weather system I’ve been discussing since last Monday (11 days ago - see the original extended notes here).

The first of these swells - due to arrive in the early hours of Saturday morning - will have been generated mainly by a sustained belt of NW winds on the eastern flank of a large Long Wave Trough in the Southern Indian Ocean. Swell periods will be quite strong thanks to several embedded features (read: small lows) within the NW flow that have displayed very strong winds in excess of 40-50kts.

Much of these winds are aimed away from our coast, but the sheer strength and duration will override the directional deficiencies and should allow for a healthy spread back into the mainland.

However, westerly swells usually create very large ranges in wave heights across the coast compared to what you’d expect at exposed part of the state - but the good news is that this direction is great for the Mid Coast. It’s the Victor stretch that dips out in the size department. 

Wave heights should building slowly through Saturday, holding into Sunday with the afternoons the pick along the Mid Coast with 2-3ft surf. Saturday is at risk of a freshening northerly breeze as a weak front slips south of the state, but I don’t there’ll be much more than 10-15kts - we should be OK for most of the day. Sunday is however the pick of the weekend with light variable winds as a ridge develops across the region.

I’m skeptical that we’ll see any great size at Victor over the weekend, and I still think our forecast model for Middleton is slightly overcalling Sunday’s size (3-5ft). To me we’re looking at smaller surf building to 2-3ft+ at Middleton on Saturday with slightly bigger waves through Sunday (3-4ft). The main points to remember is that locations close to Victor (i.e. Chiton etc) will probably be a lot smaller than usual due to the direction, however exposed locations will be bigger (Waits and Parsons often defy local shadowing effects due to their more favourable bathymetry).

Either way, conditions are looking really good both days with freshening offshore Saturday and light variable winds Sunday

Next week (Oct 5 onwards)

Sunday’s long period westerly energy will continue through Monday - I think we’ll see a similar size early morning before it tapers off into the afternoon. Moderate N’ly winds should maintain clean conditions down south, but there is a risk of some chop developing across the Mid Coast.

The rest of the forecast period looks quite exciting. Very late Monday, the leading edge of a very long period swell (Tp of around 22-23 seconds) is expected to make landfall. This will have been generated by the main engine room of the Long Wave Trough in the Indian Ocean, with another intense low migrating through the Southern Ocean with core wind speeds up to 50-60kts at times - and we’re looking at an initial W’ly swell tending W/SW over the coming days. 

This storm track looks a little better (strength/alignment/longitude) than the one expected to generate Sunday’s swell, so we can expect a little more size across the Victor region compared to the weekend. However, there will once again be a strong westerly component in the swell direction.

The main concern with Tuesday are the local winds, as a cold front pushes through the Bight. This will strengthen NW winds about the region (fine for Victor, bad news for the Mid) ahead of a gusty SW change in the evening. However, I think we’ll probably see a window of light winds at some point in the morning. Let's see how the model guidance is stacking up on Monday.

The Mid Coast should build to a solid 3ft+ throughout the afternoon (maybe a little more if the front arrives earlier than expected, and nudges up the windswell component) but the early morning is likely to be slightly smaller around 2-3ft. Down south, the initial W’ly component may shave off size at Middleton to 3-4ft in the morning however by the afternoon we’re looking at solid 4-5ft surf with bigger waves at exposed locations.

Tuesday’s swell will then ease slowly through Wednesday but it’ll be supplemented by strong short range W/SW tending SW swell from Tuesday's frontal passage. This should maintain 2-3ft surf across the Mid Coast, and the good news is that a quickly advancing ridge of high pressure should allow lighter S/SE winds to develop in the gulf, rapidly improving conditions. Wednesday could therefore see some really nice waves along there Mid Coast.

Lighter winds are also expected at Victor on Wednesday though they’ll mainly be onshore. Wave heights should remain strong here with 3-5ft surf at MIddleton. 

Wednesday’s swell is expected to hold into early Thursday before easing into the afternoon, thanks to a small blocking ridge that’ll momentarily down the swell window. This easing trend should persist into Friday.

One final of swell from the LWT progression is likely sometime next weekend - nowhere near as big or strong as what we’re expecting at other points over the preceding week - and then an extended period of smaller surf is likely throughout the following week as a general blocking pattern develops across our broader swell window.

So, make the most of the next week of waves as the following week doesn’t look anywhere near as exciting.

Craig will be back on deck on Monday to run you through the upcoming events. Have a great weekend!


Nice lines at Middleton


Just behind the inside section 

Comments

thermalben's picture
thermalben's picture
thermalben Sunday, 4 Oct 2015 at 7:11am

Nice glassy lines on the Mid this morning. CdC buoy looking the goods too! Can only imagine what Yorkes/West/KI are like...


Plenty of swell down south too (although not especially big, due to the W'ly direction).



udo's picture
udo's picture
udo Sunday, 4 Oct 2015 at 7:45am

Yorkes classic on ?

thermalben's picture
thermalben's picture
thermalben Sunday, 4 Oct 2015 at 7:48am

May have been run yesterday, if not today.

yorkessurfer's picture
yorkessurfer's picture
yorkessurfer Sunday, 4 Oct 2015 at 9:13am

The Yorkes Classic went down yesterday in super clean and offshore 3to 4ft Chinamans. The swell built during the day and I heard a few 5 footers were coming through as the afternoon wore on. Word around town was that Maxi Longhurst won the Classic but that's not official so don't quote me on it.

I didn't see any of it as I was surfing at that other spot that likes the same conditions. It was surprisingly uncrowded there considering it was a long weekend and Chi's was off limits. Lots of holiday makers in Marion Bay but I guess the allure of the West Coast must have drawn most of the keener Adelaide surfers over there?

Anyway I'm about to head down and sink my teeth into today's offerings but how's this Airforce submarine tracking aircraft that buzzed Marion Bay yesterday morning. He almost skimmed the roof of my house!


caml's picture
caml's picture
caml Sunday, 4 Oct 2015 at 2:52pm

The next storm blows up solid hey ?

caml's picture
caml's picture
caml Sunday, 4 Oct 2015 at 9:39pm

Unfortunately this amazing swell mon night is at night . Perfect big swell with nth winds and the same for vicco & tassie . All get blown out but crank in the darkness of night

caml's picture
caml's picture
caml Monday, 5 Oct 2015 at 12:16pm

Can't say I got many waves . Out of sync .hopefully the next weds is fruitier

goofyfoot's picture
goofyfoot's picture
goofyfoot Monday, 5 Oct 2015 at 12:24pm

What were the waves like caml? You surf a ds?

caml's picture
caml's picture
caml Monday, 5 Oct 2015 at 1:36pm

The highlight was a solid 10ft peak on a new design DS quad . Made the wave pretty easily and paddled super well and the drops were excellent . Wide tail was loose might need bigger fins ...

Craig's picture
Craig's picture
Craig Monday, 5 Oct 2015 at 1:40pm

Saw one of the DS' in action a coupla weeks ago.

Cam was a little overgunned but sat 50-100m deeper than us and got in early to a couple of backlit beauties. Remember one long perfect nuclear green one, looking straight in at ya while duckdiving through the face just in front, magic!

barley's picture
barley's picture
barley Monday, 5 Oct 2015 at 2:26pm

@ys i saw that plane..thought it was an orion?great weekend of waves and sundys lago was beautiful..crazy eventful bizarre weekend..all sorts of shit went down..
@craig you shouldve extended your stay for a week!
Todays fucking horrible 36+degrees and windy as fuck..beer oclock day i reckon..wed/thurs lookin the goods though..might be el nino spring?

Craig's picture
Craig's picture
Craig Monday, 5 Oct 2015 at 2:30pm

Would of but saw the crowds coming and I was surfed out :D

caml's picture
caml's picture
caml Monday, 5 Oct 2015 at 2:37pm

yorkessurfer's picture
yorkessurfer's picture
yorkessurfer Monday, 5 Oct 2015 at 2:56pm

Yeah I heard since it was an Orion too barley. I'm no plane expert but I think it was doing submarine tracking exercises because I was surfing Ethel's on Friday and the same plane was buzzing around in the waters off the coast there.
I've seen the Collins Class subs emerge randomly around here before too, even when we were out at Chi's once.
I heard since the airforce pilot flying that Orion also owns and flys that red Tiger Moth(or whatever it is) that does tourist fights around here during the summer.
Guess he just wanted to give us a thrill but gee he came in close!

yorkessurfer's picture
yorkessurfer's picture
yorkessurfer Monday, 5 Oct 2015 at 3:08pm

Here's a couple of pics of the Ledge on Friday. Would love to see a few pics of what you were surfing caml? Edit- just saw that one caml, cheers!


barley's picture
barley's picture
barley Monday, 5 Oct 2015 at 6:14pm

Sunday lago

yorkessurfer's picture
yorkessurfer's picture
yorkessurfer Monday, 5 Oct 2015 at 6:16pm

Nice pic barley!

caml's picture
caml's picture
caml Monday, 5 Oct 2015 at 6:16pm


goofyfoot's picture
goofyfoot's picture
goofyfoot Monday, 5 Oct 2015 at 6:45pm

Nice fellas

caml's picture
caml's picture
caml Tuesday, 6 Oct 2015 at 12:35am

Cdc buoy just going to 4@18 & sorrell even near 5 @ 18 . Midnight