South Australian Surf Forecast by Ben Matson (issued Monday 16th May)

Best Days: Tues: fun waves on the Mid Coast, improving down south as a new swell builds. Wed: easing clean surf down south. Thurs: good options down south with a building swell and freshening W/NW winds. Fri: fun clean waves on the Mid Coast. Sat/Sun: easing swell with offshore winds down south. 

Recap: Good waves across the weekend at Victor with a series of moderate swells and mainly offshore winds. The Mid Coast delivered small lines though nothing of any great size. Winds were mainly onshore until this morning when they swung light N/NE (they've since picked up from the north). Much smaller surf at Victor today but clean under the northerly breeze. 

This week (May 17th - 20th)

We’ve got a really good, consistent pattern of active Southern Ocean fronts at the moment. Each system is generating healthy swell for the region though the northern position of the (mainly zonal) storm track is resulting in a lot of west in the swell direction. 

This is actually a great outcome for the Mid Coast so the key to finding good waves in the gulf this week will be to look for pockets of favourable winds between weather systems. Along the Victor coastline, winds look like they’ll be generally favourable all week however the westerly component in the swell direction will limit surf size here.

Right now we’ve got a cold front steam-rolling through the Bight; a change is expected locally this evening but it’ll clear quickly to the east, leaving mainly moderate W’ly tending light NW winds in its wake. This means the best conditions will occur throughout Tuesday afternoon as the lumpiness cleans up.

This particular system has actually undergone quite a transformation over the last couple of days. During the weekend, it was positioned SW of WA with an impressive 50kt fetch aimed into the WA and SA coasts. Since then the front has tracked zonally (west-east) through the Bight, still at considerable strength though it is weakening slowly.

The combined fetch is expected to generate two swells. The short range swell will (unusually) arrive ahead of the long range swell, sometime in the early morning, with 2ft+ sets across the Mid Coast. The leading edge of the long period energy - you’ll see this on the swell period charts with the swell front showing 16-18 seconds - is due to arrive from lunchtime onwards, and it’ll kick up wave heights across the Mid Coast from early-mid afternoon onwards, with 3ft+ sets across the more reliable reefs as the tide fills in. With winds holding light from the NW there should be some good waves across the coast.

Victor Harbor should see great conditions on Tuesday once the front pushes east (i.e. possibly a little dicey early but definitely improving during the day). However, the westerly swell direction will limit surf size in close to Victor; we’re potentially looking at 3-5ft sets at Middleton with incrementally bigger surf as you head down towards Goolwa. It’ll likely be too large for Waits and Parsons (6-8ft) but conversely, these swell direction often result in only small waves at Chiton due to the shadowing from Granite Island. 

Tuesday’s swell will be largely easing on Wednesday, and with a weak front slipping to the south of the state, winds will freshen from the NW. Early morning should see some clean leftover 2ft+ sets across the Mid Coast, but it may become bumpy during the day as the wind picks up. Expect great conditions down south but with smaller, easing swells many out of the west.

Thursday and Friday are looking really good for surf potential - initially at Victor Harbor, then the Mid Coast. 

A deep mid-latitude low currently SW of WA is generating a decent swell that’s due to arrive sometime early Thursday morning, before peaking late in the day and then holding steady overnight and into Friday. This system is well positioned for the Mid Coast (apart from the large travel distance) and it’s in a better spot for Victor than tomorrow's swells; though it’ll still have quite a lot of west in its direction.

Concurrently, we’ll see some short range W/SW energy push through both coasts generated by a strong unrelated frontal passage through the Bight mid-week. This will freshen W/NW winds about the region on Thursday, before clearing to the east on Friday leaving light winds in its wake.

I’m expecting the Mid Coast to build to 2-3ft throughout Thursday (mainly after lunch) but it’s also quite likely that onshore winds will bump up the surf quite a bit. Conversely, these winds will be cross-offshore down south. Middleton should see inconsistent 4-5ft sets by the end of the day (much smaller earlier). 

A similar size range is expected through Friday, but with light variable winds across both coasts. So there should be no shortage of quality options across the region.

This weekend (May 21st - 22nd)

The weekend’s looking really good for Victor Harbor.

For the most part, conditions should be nice and clean with favourable weather as a broad upper level ridge amplifies across the region. This should deliver moderate northerly winds on Saturday, becoming fresh and gusty on Sunday and veering NW as a series of fronts rear up from the west.

Friday’s solid swell will ease throughout the weekend but early Saturday should still see plenty of energy, with 3-4ft sets at Middleton and small waves at Chiton. By the afternoon we may see wave heights becoming manageable for Waits and Parsons (they’ll be ideal on Sunday, mainly the morning before the wind gets too strong).

The Mid Coast will see easing swells all weekend but I’m concerned that Saturday’s northerlies could kick into gear early. As such I reckon a Victor mission is a more likely option at this stage. Sunday will be tiny in the gulf so no need to consider anything other than a South Coast trip. Let’s take a closer look on Wednesday. 

Next week (May 23rd onwards)

The storm track look to remain in fifth gear for the long term period, which means there’s no end in sight for South Oz’s run of solid waves. 

Over the weekend, the upper level ridge across the SE corner of the country - almost a blocking pattern - will bank up a series of advancing fronts, with multiple low pressure centres (a couple in the Bight, and a big parent low close to Antarctica). 

These fronts will push through on Sunday evening, but the timing’s not confident right now - at this stage we could be looking at light winds by Monday morning, and a solid combo of west and south west swells in the water, ideal for both coasts (initial ball park size range of 2-3ft on the Mid Coast and 4ft at Middleton).

Model guidance is suggesting a temporary break in the wake of this system followed by another lengthy spell of fronts that should maintain moderate to occasionally large surf through the back half of next week, the weekend and the start of the following week. And it’s not even winter yet!

Let’s take another look on Wednesday.