South Arm Surf Forecast by Ben Matson (issued Wednesday 26th October)

Features of the Forecast (tl;dr)

• Interesting E/SE swell for Thursday, generally small in the South Arm but novelty spots will be worth a look
• Same for Friday, though size will be easing, and winds will swing W then SW
• Generally poor weekend
• Tiny and windy early next week
• Better surf prospects from Tues thru' Sat as a series of winteresque storms push through our swell window

Recap

Seems like we're in the midst of a never-ending pattern of small surf and onshore winds. Though we are seeing some building E/SE swell.

This week (Oct 27 - 28)

A broad, slow moving low pressure system across the Tasmanian region has a broadening, lengthening E/SE fetch extending eastwards into the southern Tasman Sea (see below).

This is an unusual swell source for the South Arm (and indeed, the entirety of Storm Bay) on a number of fronts - firstly, the fetch alignment, and secondly, its stationary pattern and thus lengthy duration. 

Ultimately, the fetch angle is still a little acute to properly benefit the South Arm, compared to (say) the southern end of the East Coast, which is seeing solid surf this afternoon. What this means is that inside Storm Bay, we'll see little to no surf from this source across west facing locations (i.e. the eastern coastline), the inner reaches of Tiger Head Bay; even the rusually reliable open beaches haunts such as Clifton are likely to see small levels of swell from this source, perhaps reaching a bumpy 2ft+ tomorrow. 

However, the more eastern exposures of the South Arm, plus some unusual coasts of Bruny Island and possibly even up into novelty spots just inside the Derwent River should pick up some useful E/SE swell. 

I'm not willing to put a size on these coasts as they simply don't break very often, but it may be worth sniffing around to see if there are waves breaking where waves often don't break. Theoretically, a fetch like this off any other exposed east facing coast in Australia would be worth 6ft+ sets, though I'd be extremely hesitant expecting anything locally of this size. 

Also, bear in mind that lingering SE winds will take the sheen off surface conditions. 

As the low tracks eastward into Friday, we'll see the synoptic wind swing to the SW, which may become light W'ly for a period early morning, before strengthening SW into the afternoon.   

Whatever E/SE swells make landfall on Thursday will start to ease back on Friday, so again, using some imagination there is certainly a chance for some interesting waves across exposed east facing coasts in the morning, before the wind gets too strong into the afternoon. 

This weekend (Oct 29 - 30)

Nothing special is expected this weekend.

The Southern Ocean's storm track has been positio

However, we'll be uder a post-frontal W/SW airstream, gusty at times, so conditions don't look great.

ned out ouf or ideal swell window for some time, though activity near Heard Island earlier this week generated some new long period swell that will start to show on Friday (beneath the local E/SE energy) and should provide small 1-2ft sets on Saturday (the Thurs/Fri unusual E/SE swell will be easing, but may still show some leftover sets at novelty spots).These swells will throttle back to babyfood on Sunday with lighter winds. 

So the weekend isn't looking great, unfortunately.

Next week (Oct 31 onwards)

We've got plenty of surf due into the long term period, as a Long Wave Trough amplifies across the entire southern expanse of the continent.

It's still a little early to pin down specifics, but early indications are for a week or so of strong to gale force W'ly winds, with initially tiny surf on Monday starting to build into Tuesday as a series of groundswells make landfall. 

However, surf prospects are much better for the second half of the week (and next weekend), as the storm track charges nicely through our primary swell window with a series of back-to-back polar lows and fronts. This should produce plenty of surf in the South Arm though it will be quite windy, so we'll be looking for those peaks in size that will allow for enough size to favour sheltered spots. 

Let's wait and see how Friday's model runs hold out, eh? Fingers crossed.