South Arm Surf Forecast by Ben Matson (issued Monday 8th June)

Best Days: Wed/Thurs: small fun surf at exposed beaches, a little windy Wed PM but OK. Fri: decent new pulse of swell, early light winds.

Recap: We’ve seen a succession of small swells over the last few days with mainly light W/NW winds. 

This week (June 9 - 12)

*This week's Forecaster Notes will be a little sporadic, and sometimes brief, as Craig is on leave*

The storm track below the continent has been quite zonal (west-east) over the last few days and although vigorous, is resulting in in a lot of west in the swell direction. Several intense lows are embedded in the current pattern and will be responsible for several new swells through the second half of this week.

Today’s small swell will ease slowly into Tuesday with similar winds out of the NW through W/NW, at strength. As such, except very small surf across most of the South Arm.

A new long period swell will arrive on Wednesday morning, generated by the first polar front/low in the approaching sequence. Whilst the morning will probably start off small and undersized (with a brief window of small clean waves east of Melbourne), surf size will rebuild during the day and with strengthening NW tending W/NW winds we should se the afternoon build into the 2-3ft range. 

A shallow SW change is expected on Thursday. No major strength is likely in the wind and we’ll probably see early light W/NW breezes but we can’t rule out a moderate deterioration in surf quality during the day. Surf size should remain steady, somewhere in the 2ft+ range at most open beaches though size may dip slightly as the day wears on.

Friday is shaping up nicely, with another pulse of moderate W/SW swell originating from a trailing polar low in the sequence below the continent later Wednesday (see below). This is expected to rebuild size back up into the 2-3ft+ range, if anything this swell looks the most promising for the South Arm this week as we’ll be on the tail end of the frontal sequence and the fetch will be a little more SW in alignment. 

Local winds look reasonably good, with early light winds freshening from the N/NE during the day  as a high pressure system builds rapidly to the east of Tasmania. This should favour most of the beaches quite well. 

This weekend (June 13 - 14)

At this stage it's looking like a small, windy weekend ahead with limited surf options. 

Friday’s swells will fade steadily into Saturday, and a vigorous frontal passage pushing through the Bight will strengthen N/NE winds to gale force strength. The first front in this next progression will cross the coast into Sunday swinging winds to the NW or maybe W/NW, at considerable strength. 

However, the associated storm track looks like it’ll initially be riding way too high in the Bight, so at this stage I’m expecting tiny surf throughout the South Arm all weekend. Only Saturday morning has a any potential, offering the tail end of energy from Friday’s pulse. On the whole, give it a miss.

Next week (June 15 onwards)

We’ve got an active long wave pattern expected for next week with an extended run of windy conditions from Saturday through until the end of next week. 

Monday will see building swells from several sources, some of which will be quite distant: the early incarnation of this pattern SW of Heard Island from tomorrow onwards (see chart below) will generate some decent long period swell - the leading edge arriving Sunday afternoon, but not really showing properly until Monday. 

In any case it’ll be overshadowed by larger swells generated by closer storms associated with the same pattern. The primary one is expected to intensify south of the Bight on Sunday and should project a large SW swell that’ll build during Monday and peak Tuesday, reaching 3ft+ across the South Arm. This is a somewhat conservative number given the strength of this system, but current model guidance places it a little too west of our swell window to see any major size. 

Further strong fronts trailing behind will generate more large swells for the region later in the week but they’ll be quite west in direction which will attenuate a lot the size through Storm Bay. So, we need to keep a lid on our size expectations for now.

Either way, there’s plenty of synoptic action ahead.

See you Wednesday.