Victorian Surf Forecast by Ben Matson (issued Monday 21st September)

Best Days: Tues: protected locations only as the swell builds. Wed: should be an early window of offshores in Torquay. Thurs: fun morning waves on the Surf Coast. Fri: small bump in new swell with good winds for most open beaches. Sat/Sun: light winds and plenty of waves for both coasts, tho' inconsistent.

Recap: Plenty of fun waves over the weekend with 3ft sets along the Surf Coast and 5-6ft waves east of Melbourne, and offshore winds both days keeping conditions clean just about everywhere. Surf size eased a little this morning and early NW winds preceded a gusty SW change that reached the Aireys Inlet AWS around 10:30am. Winds have recently veered back to the W so the Surf Coast is still quite manageable. The Cape Sorell buoy has picked up the leading edge of a new long period swell (Tp 18 seconds) in the last few hours but there’s been no major size increase at the coast yet.

This week (Sep 22 - 25)

We’ve got a couple of swell sources for the short term.

The new long range groundswell recently detected at Cape Sorell should provide a small increase from tonight into Tuesday. It was generated by a severe low pressure system located near Heard Island during the middle to latter part of last week, and generated very large waves for West Oz yesterday. However, the extra couple of thousand kilometres of travel distance means we’re seeing a much smaller size in Victoria due to the effects of swell decay.

In addition to this swell, the front responsible for today’s change (in actual fact, there are two fronts - one that arrived this morning and another due to cross the coast tonight) will generate some short range SW swell for Tuesday, but it’ll be lower in quality.

A third swell source for the next few days will push through later Tuesday, originating from a second severe low pressure system near the Heard Island region on Friday. It tracked below the continent over the weekend and we should see a corresponding kick at the Cape Sorell buoy around lunchtime (Tp of 16-17 seconds), with the swell filling into Central Victorian beaches late in the day, before peaking overnight and then easing through Wednesday.

Unfortunately, local winds are not looking very favourable on Tuesday, thanks to a developing low pressure system in the Tasman Sea and a broad high in the Bight, which will direct strong S/SW winds across most locations. There is an outside chance for a period of early W'ly winds across the Surf Coast for an hour or two at dawn, but confidence is lower than usual for this local anomoly as the synoptic southerly looks like it’ll be quite strong, and well established overnight Monday. So, don't get your hopes up for anything amazing.

Wednesday will see lighter synoptic winds as the pressure gradient relaxes, and therefore there’s a much better chance of an early light offshore breeze along the Surf Coast. But in general expect a dominant southerly flow. 

So, how much size will we see? I haven’t had much of a chance to review the hindcast data from the weekend, but for now I can’t see much reason to deviate from Craig’s estimates on Friday for the Surf Coast to building from 3-4ft to 4-5ft during Tuesday, easing from 3-5ft Wednesday. Note: our surf model is calling a peak on 5-6ft in Torquay late Tuesday (see image below) however I think this is probably a slight overcall, as the wave model is combining two swell trains into one (note the jump in size on the long period swell from 2.1m to 3.7m between 6am and 12pm Tuesday, this is the giveaway and therefore the raw data should be treated with caution).

East of Melbourne it’ll be very large on the open beaches but Tuesday should have good options at protected locations inside Western Port into the afternoon as the swell builds. Even Wednesday morning may have smaller leftovers with much lighter winds however the trend will be downwards throughout the day.

The trend for the rest of the week is then slowly down through Thursday with light winds (small fun waves in Torquay), ahead of a bump in energy on Friday, originating from a polar low developing east of Heard Island today that’s expected to remain very low in latitude for the coming days. 

Strong core winds should result in a decent leading edge swell period (around 15-16 seconds) and a slow upwards trend is likely during the day with inconsistent 2-3ft+ sets on offer in Torquay by the late afternoon. Winds are expected to tend light NE as a high pressure system migrates just south of the region, so this will favour the open beaches both east and west of Melbourne (east should see a late peak in the 4-5ft+ range). 

This weekend (Sep 26 - 27)

Looks like we’ve got a great weekend of waves ahead for all regions. 

A dominant high pressure system is expected to maintain light winds across all coasts, and a series of strong polar lows developing all week in our far and mid range swell windows should generate a couple of pulses of quality swell that’ll deliver plenty of great waves across the coast.

Early indications are for inconsistent both days somewhere in the 2-3ft+ range west of Melbourne, and 4-5ft+ east of Melbourne. I’ll have more on this in Wednesday’s update.

Next week (Sep 28 onwards)

Nothing major on the radar for next week at this stage.

We’ve got a couple of fronts expected to push through our swell window on the weekend that should renew more energy for late Monday or Tuesday (say, 2-3ft+ Surf Coast), and the only other feature I’ll be keeping a close eye on is a possible amplifying node of the Long Wave Trough in the south-eastern Indian Ocean (i.e. east of Heard Island) early next week that may spawn a series of intense fronts and lows, with a strong resulting groundswell arriving in Victoria later next week or (more likely) into the following weekend. More on this over the coming days.