South Arm Forecast by Ben Matson (issued Friday November 8th)

Features of the Forecast (tl;dr)

• Building swell all weekend, looking best Sunday afternoon
• Great waves early Monday with light winds and a strong swell
• Easing size on Tuesday though still fun
• Small optoins Wednesday/Thursday
• More swell Friday onwards

Recap

Surf size has been very small for the last few days with no real waves to speak of.

This weekend (Nov 9 - 10)

The weekend is still looking very promising.

Broadly speaking the size trend will be up slowly Saturday and early Sunday, peaking into the afternoon and probably holding into Monday.

Swell models are still suggesting a timeline some 12-24 hours ahead of my estimation (i.e. an easing trend kicking in from Sunday afternoon onwards) but my analysis of the charts is that the models are not properly resolving a reinforcing swell behind the main peak (due Sat/Sun), sourced from a secondary polar low, which will prolong the peak into early Monday.

Regardless, the weekend’s best options will be late in the day on Sunday.

The early stages of the synoptic system generating this swell event were generally aimed outside of the South Arm’s swell window, so we won’t see much size to begin with on Saturday. The trend will however be upwards, and early light NW winds will probably swing moderate W/SW through the afternoon.

Sunday’s looking at a reduced window of early local W/NW winds before they swing moderate SW mid-morning as a front slides south of the state. Wind speeds won’t be too strong though (and should ease after lunch) of which we should see size building to a solid 2-3ft+ by late afternoon (a touch smaller earlier). It’ll be well worth scouting around for options in the afternoon.

Next week (Nov 11 onwards)

Monday still looks like the best day of the forecast period, thanks to the intensification of a polar low well SW of the state on Saturday (see below). This will generate a long period SW thru S/SW groundswell that will more efficiently wrap into Storm Bay thanks to the favourable swell direction.

I’m expecting size to peak around 3-4ft+ across most open South Arm beaches in the morning (easing later), and winds should be light and variable for most of the day ahead of afternoon sea breezes. 

Generally OK conditions are expected for the rest of the week with no major synoptic drives expected locally, though we will see some influence from a coastal trough at times. Surf size will ease into Tuesday (2ft+ down to 1-2ft) before bottoming out on Wednesday and then pulsing back again on Thursday with a new swell, thanks to modest frontal activity in the Southern Ocean all week.

The models are still showing another strong front moving through the Southern Ocean early in the week which will setup a swell renewal for Friday, though they have downgraded a touch so I’m ballparking size range in the 2ft+ range for a couple of days around Friday. This will still be a very good result for mid-November.

Long term activity remains quite boisterous with a whole heap of polar lows developing through our swell window, keeping us busy through the last two weeks of spring. 

Have a great weekend!