thermalben

Solid weekend: half windy, half clean

South Australian Surf Forecast by Ben Matson (issued Friday 18th October)

Best Days: Sat: large windy surf at Victor, slim chance for early W/NW winds. Solid and bumpy on the Mid. Sun: large and cleaning up quickly down south, great on the Mid with light winds. Easing swells from Mon/Tues with light winds. Nice new swell for the Mid building Wed with light winds (good down south), holding into Thurs with a risk for an onshore change.

Recap: The Mid Coast saw average bumpy waves on Thursday with moderating W/SW winds. Today was smaller with early light winds quickly picking up from the NW. Victor offered workable surf early Thursday with moderate W’ly winds before they swung fresh SW. Smaller, cleaner surf padded out this morning under moderate NW winds. They’re now gusty W/NW. There’s currently no sign of a major groundswell increase on the South Coast surfcams yet, though the buoy is showing a strong increase in windswell (associated with the strengthening W/NW airstream).

Small waves at South Port early this morning before the wind got too strong

This weekend (Oct 18 - 19)

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Post-frontal W/SW winds will maintain strong to gale force strength across the Victor coastline on Saturday. There’s an outside chance for a brief window of early W/NW winds but it’s only low confidence. Winds will be lighter on the Mid but still enough to create unwelcome bumps. 

As for surf, we’re still looking at large swell event building steadily through Saturday, peaking overnight and then trending slowly down into Sunday. 

The source of this swell is a very strong, broad cold front and associated polar low (and another strong system preceding this, earlier in the week), of which satellite data now shows core winds within the polar low were slightly under that predicted by the models all week. Whilst I still think we’ll see peak surf size pushing 6ft, maybe 6-8ft at Victor’s swell magnets, it’s now likely to be of much shorter duration. Early Saturday may be a little undersized too.

Across the Mid Coast, we’ll see wave heights building into the 3ft+ range by the afternoon, but conditions won’t be great.

Sunday looks a lot different though. 

A ridge of high pressure moving in from the west will rapidly weaken the pressure gradient and ease local wind speeds. The Mid Coast should maintain 3ft sets on the more favourable parts of the tide, and it’ll be clean with light variable winds and sea breezes. 

At Victor, the early morning peak in size will coincide with a light variable wind - probably S/SW for much of the day but with a chance for isolated regions of W/NW winds in the morning. This should clean up the wave faces though the lineup will remain lumpy from Saturday’s winds. Most spots will be maxed out (6ft+ sets, possibly bigger) so it’ll be a day for those more sheltered breaks closer to Victor Harbor. Expect size to ease a little during the day.
 
Next week (Oct 20 onwards)

Monday, Tuesday and Wednesday all look great at Victor with early light offshore winds and afternoon sea breezes, and initially strong though steadily easing swells. Monday morning should maintain 4-5ft sets at Middleton, easing to 3-4ft by the afternoon and smaller into Tuesday. 

We’ll also see a similar swell/wind trend along the Mid Coast though with much smaller surf. Monday may see the odd 2ft set but expect longer breaks between waves. There won't be much size on offer by Tuesday.

On Wednesday, the leading edge of a very good quality groundswell will make landfall.

It’s being generated by a powerful, unusually stationary low and front in the central/southern Indian Ocean (near Heard Island) which is expected to remain in the same position for the next few days - this doesn’t happen very often in this part of the world. It’s also a shame it’s positioned so far from our coast as we’ll see a significant size loss by the time it reaches South Australia, and therefore the sets will be very infrequent. The fetch is also much better aimed towards Indo and WA so we'll see smaller sideband energy thank other regions in the direct firing line.

I do however like the alignment of this system for the Mid, so despite the lengthy travel distance I think we’ll see 2-3ft sets by late Wednesday and into Thursday (bear in mind, it'll be extremely inconsistent). The W/SW swell direction will probably cap size at Victor, perhaps 3ft+ at Middleton though much bigger at exposed spots. 

Wednesday looks clean with generally light NE winds and sea breezes, however Thursday looks tricky - initially the morning should be OK but a series of strong fronts are likely from the afternoon onwards. 

So, pencil in Wednesday for a session, probably after lunch for the most size potential. 

Our Wed/Thurs swell will probably maintain size into Friday but an unrelated deepening cut-off low approaching from the west will bring about a renewal of large, windy surf conditions throughout the day, persisting into Saturday.

More on this in Monday’s update. Have a great weekend!

Comments

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thermalben's picture
thermalben commented Friday, 18 Oct 2019 at 5:25pm

Solid (though onshore) on the Mid now.