Victoria Forecast by Ben Matson (issued Monday 27th March)

Best Days: Tues: small waves in Torquay. Wed: solid building swells in Torquay with mainly good winds, reaching a large peak Thurs though with a threat of onshores. Great options in Western Port these days. Fri: solid but easing swells, again best suited to the Surf Coast and Western Port. Sat/Sun: another large swell, this time more SW thru' S/SW with likely light winds. 

Recap: Long period swell energy built slowly all weekend and winds remained generally favourable for the open beaches Surf size peaked around the 2-3ft mark across the Surf Coast with 4-6ft sets east of Melbourne. The swell is less consistent today but we are seeing strengthening N’ly winds ahead of a W’ly change. 

This week (Mar 28 - 31)

We’re still on track for a very large, powerful swell to arrive mid-late week. But there are several stages of swell ahead and with a tricky wind outlook we need to hone into the specifics.

The developing frontal progression through the Southern Ocean is broad, and encompasses a couple of surface low pressure centres. The first is a cut-off low in the Bight, which is crossing the SA coast right now and will reach us later today. However, this system is riding high in the Bight and its swell generating fetch is tucked up tight inside Victoria’s acute western swell window. If anything, much of the regional swell (i.e. outside Cape Otway) will have a touch of W/NW. 

This means that although sizeable swells will develop across exposed oceans, we’re going to see much smaller surf across the central Victorian coast - more so Torquay than anywhere else, and this is a shame as winds will be ideal for this region as the swell builds through Tuesday. Reliable reefs across this region may see stray 2-3ft sets but for the most part I’m not expecting anything appreciable west of Melbourne. A building trend is expected through the day so anticipate smaller surf early morning.

East of Melbourne, winds won’t be conducive for the open beaches on Tuesday (which will be to big anyway) yet the swell will probably be too west and slightly too small for anything amazing inside Western Port (for which surface conditions will also be very good).
 
While this is happening, a deep polar low SW of Western Australia will have have extended a broad fetch to merge with the cut off low in the Bight, and the resulting swell generating system looks to be a doozy - a couple of thousand kilometres of W thru SW gales across the Southern Ocean.

Initially, the early stages will also have a strong westerly component and this will again limit size in Torquay though we’ll see a strong building trend through Wednesday. 

The real juice will kick in on Thursday; this energy will be sourced from the polar low itself which will be trailing at the back end of the fetch though will be working on the active sea state generated by three days of westerly gales prior. 

I think that our surf model is undercalling this event, though it’s worth noting that almost all of the swell production occurs west of 130E as the fronts work their way around a slow moving node of the Long Wave Trough (winds east of this point have to much north in their direction to benefit Victoria). 

For reference, this point is approximately inline longitudinally with the WA/SA border, so we do need to factor in swell decay from this point (some 1200-1500km). However the sheer breadth and length of the fetch should override some of the travel deficiencies. 

The other issue this week is that whilst Wednesday’s steady increase will be accompanied by mainly freshening NW winds as a front approaches from the west, we are looking at a SW wind change some time on Thursday morning. Fortunately, the models are suggesting only moderate to fresh strength will trail the change and this should allow for some local topographical influence across the Surf Coast, swinging the early morning breeze around to the W or even W/NW here. Other coasts won't fare as well though.

And onshores are certainly a threat for Thursday. 

So, size? Wednesday should kick off in the 3ft range across the Surf Coast (a mix of new and leftover swell) but then build towards 5-6ft by the end of the day. Wednesday is probably the safest bet overall as we’re looking at a longer window of offshore winds. 

Thursday should kick up another notch with more consistency as the swell swings a little more SW, with bomb sets occasionally pushing 6-8ft at reliable swell magnets west of Melbourne (generally 5-6ft across most open Torquay beaches and reefs). As mentioned earlier, a brief window of W/NW winds are possible but otherwise expect moderate SW winds throughout the day.

East of Melbourne will see much larger surf (building to 10-12ft by Thursday) so obviously Western Port will be a much better choice these days. However bear in mind that Wednesday morning may be a little undersized in this neck of the woods. 

We’ll then finish the week off on Friday with large but steadily easing swells with lighter W’ly winds, probably NW across the Surf Coast. Early sets should manage 4-6ft though it’ll likely be down to 3-4ft by the end of the day. 

Again, Western Port should also be a great option on Friday for surfers east of Melbourne.

This weekend (Apr 1 - 2)

The interesting thing about this week’s upcoming swell on Wednesday, Thursday and Friday is that it'll probably be a distraction, and many people many not realise that there’s a likely better swell inbound for the weekend. So don’t over-froth too hard over the coming days as there’s more to come.

A deepening polar low is expected to reach maturity well south of WA (off the Ice Shelf) from late Wednesday through Thursday, and wind strengths are likely to max out in the 60kt+ range (check the MSLP and 10m wind chart below!). Whilst smaller in length and size than the mid-week system, the more southern AND eastern position of this low means that the resulting swell will have more south in direction (i.e. SW tending S/SW) across Victorian beaches. This should narrow the possible size range between the Surf Coast and the East Coast (read: slightly bigger waves than normal for Torquay). 

Additionally, it looks like it’ll remain at relatively low latitudes, which is good as it’ll ensure locally light winds as the swell reaches the mainland.

At this stage we can expect long period forerunners reaching the coast on Saturday morning with a rapid increase in size throughout the day. Reliable Surf Coast reefs should nudge 6-8ft by the late afternoon if the models don't significantly downgrade; 8-10ft surf is likely east of Melbourne. 

Wave heights will then ease steadily through Sunday - so it's shaping up to deliver another morning of likely large surf in Torquay.

As for winds, its looking to be pretty good under a relatively weak synoptic flow, offering light variable airstreams - though ‘variable’ implies any direction, which could be onshore. I’ll have more idea on this in Wednesday’s update.

Next week (Apr 3 onwards)

It’s a long time away but there are more fronts stacking up in the Southern Ocean so the swell potential for the second half of next week is also very good for Victoria.