Large swells on the way

Ben Matson picture
Ben Matson (thermalben)

Victoria Forecast by Ben Matson (issued Monday 11th March)

Best Days: Tues: brief early window of W/NW winds and fun waves in Torquay. Wed: large, slightly lumpy swells with light winds, easing steadily Thurs with good conditions. Fri: renewal in swell, though light/moderate onshore. Sat/Sun: good surf east of Melbourne.

Recap: Saturday delivered building SW groundswells with mainly light winds; the Surf Coast saw 4-6ft sets through the lunchtime peak, even the odd bigger bomb, with larger surf east of Melbourne. Wave heights eased steadily into Sunday, with the Surf Coast abating from 2-3ft, and locations east of Melbourne easing from 4-5ft. Light morning winds gave way to strengthening NW breezes with gusts reaching 38kts at Aireys Inlet around 2pm, before a SW change filled in afterwards (light on the Surf Coast, moderate to fresh east of Melbourne). This morning has revealed moderate W/NW winds east of Melbourne, lighter west of Melbourne, with a low point in surf size ahead of a building trend throughout the day.

This week (Mar 12 - 15)

Today’s Forecaster Notes are brought to you by Rip Curl

*this week's Forecaster Notes will be occasionally brief and erratic, as Craig is on annual leave*

So, first day back in the Victorian driver’s seat for a while, and what do we have?

Oh crap.. Craig’s Friday forecast estimated 6-8ft in Torquay early Wed with OK winds? OK, let’s take a quick look at the available data to see if the model guidance is still stacking up (time is limited today, so it’ll be a brief scan of some key indicators).

First up: ASCAT winds. And they were largely offline over the weekend. Bugger.. I can’t verify surface wind speeds against model guidance.

Looks like Craig’s forecast was pretty good for the weekend’s large swell - both in eventual size, and timing, as the downward flank was pretty steep, which is hard to be confident in - so this adds confidence to his Tues/Wed estimate.

And assessing the actual position of the storm right now - based on analysis charts - looks pretty healthy (see image below). I really like the look of this system, its position relative to the coast is in the ‘goldilocks’ zone, reaching peak intensity between Margaret River and Adelaide longitudes, beginning to weaken as it approaches Victorian latitudes.

This will allow the groundswell sufficient time to develop properly, but also mean local winds won't impact the quality of the waves quite as much as a frontal system amplifying through Bass Strait. With the core swell production sitting at around 50S, swell direction should be somewhere between W/SW and SW. Core winds are above 50kts and the bulk fetch is 30-40kts, which is typical for a strong autumn swell generator.

The associated front will push through on Tuesday morning, delivering gusty SW winds throughout the day (morning window of W/NW winds in most areas). Craig mentioned a swell increase for this afternoon (Monday) holding into Tuesday which is more difficult for me to verify at short notice because (1) the leading edge hasn’t yet shown at Cape Sorell, and (2) hindcasting the synoptic would take an additional 15 minutes, which I don't have. So I’ll take his word on it.

This means early Tuesday should offer a brief window of fun surf west of Melbourne in the 3ft range. 

Behind the front, we’ll see the groundswell kick in properly through Tuesday afternoon, building to an overnight peak before slowly easing through Wednesday. I can’t see any reason to adjust wave heights from Craig’s estimate of 6ft to occasionally 8ft at the Surf Coast magnets, 8-10ft on the Mornington Peninsula. However, this size forecast is for the more exposed breaks so expect smaller waves elsewhere, especially sheltered spots. 

The main issue for Wednesday will be the local winds. The front will clear rapidly to the east into Wednesday, but a follow up cut-off low trailing behind will be too far away to steer the winds around to the NW (as we commonly see in winter). This means light variable winds across the Surf Coast, however the absence of an offshore breeze will result in lumpy conditions, though it’ll be clean on the face. Light to moderate S’ly winds may linger across the open beaches east of Melbourne. But, protected locations inside Western Port Bay et al should see great surf on the more favourable parts of the tide.

Wave heights will continue to ease into Thursday with mainly light winds (fun surf in Torquay, in and around the 3-4ft mark early, smaller into the afternoon) ahead of a new swell arriving very late Thursday or overnight into Friday, from the cut-off low mentioned above. This low looks impressive on the charts with strong winds around tight centre, but the fetch length is short, which reduces its size/duration potential, and its ability to favour protected locations.

We should see 3-4ft+ surf in Torquay on Friday, perhaps the odd bigger set at times, with 5-6ft surf at the open beaches east of Melbourne. Winds will swing southerly as the low passes to the east of Victorian longitudes but it won’t be too strong so conditions should be workable. Well worth a surf but likely a notch or two below average for autumn. 

This weekend (Mar 16 - 17)

Friday’s swell will slowly ease through Saturday and Sunday. We should still see decent surf to start the weekend west of Melbourne with early 3ft+ sets but it’ll ease to 2ft+ during the day and then smaller surf is expected on Sunday. 

Conditions actually look best for the open beaches east of Melbourne with a ridge of high pressure to the south-west directing moderate easterlies across the coast, keeping the open beaches nice and clean. We’ll see more size here with sets in the 4-5ft range early Saturday (also easing during the day). 

Lighter, more variable winds are expected on Sunday. In addition to the easing SW groundswell, the Surf Coast may also pick up a small SE windswell from Saturday’s easterly fetch through Bass Strait, but it probably won’t amount to a great deal of size. Worth keeping a close eye on though.

Next week (Mar 18 onwards)

Nothing major on the long term charts at this stage though a steady progression of strong polar fronts and lows through the Southern Indian and Southern Oceans will maintain (at a minimum) persistent, pulsey moderate SW groundswells for quite some time. 

Comments

Nick Bone's picture
Nick Bone's picture
Nick Bone Monday, 11 Mar 2019 at 7:50am

Up and atom this morning Benny boy

willibutler's picture
willibutler's picture
willibutler Monday, 11 Mar 2019 at 2:02pm

You call this brief? This is way more detailed than any of Craig’s notes ahahha

thermalben's picture
thermalben's picture
thermalben Monday, 11 Mar 2019 at 2:26pm

I know, I know. Too hard to resist.

ShaneK's picture
ShaneK's picture
ShaneK Monday, 11 Mar 2019 at 3:27pm

Any more precise guide on that wind change tomorrow morning for Surf Coast? It looks touch and go to getting a window....

goofyfoot's picture
goofyfoot's picture
goofyfoot Monday, 11 Mar 2019 at 3:47pm

It will be NW winds until 9:27

willibutler's picture
willibutler's picture
willibutler Monday, 11 Mar 2019 at 4:59pm

I thought it was 9:28?

blackers's picture
blackers's picture
blackers Tuesday, 12 Mar 2019 at 12:12pm

Good call boys, the South Channel Island reading shows it went SW around 9.15.

ShaneK's picture
ShaneK's picture
ShaneK Tuesday, 12 Mar 2019 at 12:39pm

Yeah, maybe I'll stop subscribing to Swellnet and just call up you guys...hahah

Airey's went WSW at 8am!

yourightgeezer's picture
yourightgeezer's picture
yourightgeezer Wednesday, 13 Mar 2019 at 3:32pm

Any Wednesday forecaster notes plz?

thermalben's picture
thermalben's picture
thermalben Wednesday, 13 Mar 2019 at 3:35pm

They'll be up later today (notes above have "this week's Forecaster Notes will be occasionally brief and erratic, as Craig is on annual leave").