O Roaring Forties, Where Art Thou?
Where art thou strong winter cold fronts?
This is the question many Victorians are wondering, not because the cold and rain haven't hit, quite the opposite, but because we're not seeing the strong Southern Ocean frontal progressions we usually see at this time of year moving through.
As you may have read across the site over the past year, the Victorian winter of 2020 was a non-event for swell, further compounded by lockdowns, and once spring and summer kicked into gear, a developing La Niña didn't offer much in the way of quality surf at all.
Moving into 2021, there was one month of great waves on the Surf Coast, that being April, but since then the Southern Ocean has fallen relatively quiet. Instead of the classic Southern Ocean frontal progressions, we've had mid-latitude lows and troughs following a more northerly path. This isn't great for swell generation as the storms themselves are small in scope and their northerly track results in westerly swells which get blocked by Cape Otway.
On the plus side, these mid-latitude systems bring out-of-season winds from the north-eastern quadrant, favouring the the exposed beaches. You just had to have a good patch of sand up your sleeve.
With the winter solstice passing yesterday (the shortest day of the year), the winter proper is now underway, but having a quick look at the long-range charts, there's still nothing quite like what we saw in April shaping up for the southern states.
I've brought up the probability charts from the European Centre for Medium-range Weather Forecasts (ECMWF) regarding the outlook into the middle of July.
What's shown is the forecast Mean Sea Level Pressure weekly anomalies for next week (Monday 28th June - Monday 5th July) and the following week (Monday 5th July – Monday 12th). The anomaly is the difference from the long-term climate average and what can be clearly seen into the first week of July is a high sitting across the southern Tasman Sea, spread out across New Zealand (and further east), with a low pressure anomaly dip to the north of New Zealand's North Island, through the Coral Sea.
Also a low pressure anomaly extending from west of WA, across into the Bight, though stopping just east of Adelaide also stands out.
The second week which heads towards the middle of July (displayed at the bottom of the article) shows a weaker version of next week, with the same main features.
So what does this equate to for surf? Knowing that highs spin anti-clockwise and lows clockwise, unfortunately for Victoria with that high stretching across the southern Tasman Sea and low sitting across Western Australia, we'll see storms projected up from the Southern Ocean, towards Western Australia and quite high in latitude, before dipping back down to the south on approach to Victoria.
This is a continuation of the current poor setup, with mid-latitude systems pushing in from the west but sliding south-east, bringing favourable northerly winds but no swell of significance.
If the low pressure anomaly was further east and positioned, directly west of or over Tasmania, we'd be looking at a more favourable forecast for swell generating fronts for the Surf Coast, but alas. Yet this isn't the case.
Instead, Western Australia will cop frontal activity from Sunday, with large, stormy surf due most of next week, improving the following weekend though with no quality swells to follow.
Looking to the east and we've got quite a juicy setup projected for all locations.
That low pressure anomaly being cradled by the broad high, persisting even into the following week indicates that we're in for some form of a quality swell producer from the east.
Similar to other setups we've already seen this year, easterly trades extending out into the western Pacific Ocean should produce a prolonged easterly swell event from late next week, into the following week, biggest across south-east Queensland and northern NSW, grading smaller further south.
Whether we see a more substantial low developing around the New Zealand region is still unsure but the outlook is positive.
At this stage there's still no indication on when we may see the 'Roaring Forties' kick back into gear under the country, and the reason for this still isn't too clear, though keep an eye out for a second article in the coming week outlining one of the possible contributing factors.
For now, the wait continues for Victorian surfers.