Rip Curl WSL Finals - Early Forecast
With the canning of the Tahiti Pro, the Woz moves onto the next, and final, stop of the 2021 Championship Tour: the Rip Curl Finals at Trestles. The first time the Woz has used a finals series to decide the world champion.
The contest will be a one-day affair, with a waiting period running from Thursday the 9th of September through to Friday the 17th.
Like the Salina Cruz coast, where the CT last stopped, Trestles relies on long-range southerly swell energy from the South Pacific Ocean. Any swells, unless huge, from the north-west to south-west are blocked by the Channel Islands, with swells from the south to south-southwest squeezing in the gap between San Clemente Island and the mainland.
Also similar to Mexico's outlook, with swell travel time in the vicinity of seven to ten days, and a good idea on the swell-generating systems firing up for the event over the coming fortnight, we already have a good gauge on what's in store for the whole waiting period.
Ideally, we want Southern Ocean storms to fire up east of New Zealand, though not too close, but also not so far east that they're off the Chilean coast. This allows swells to travel past the French Polynesian Island Chain, but also prevents them being primarily focussed into Central America and Mexico. The more south in the fetch once the storm is east of French Polynesia, the better aligned it is for California.
With this in mind we're looking at swell travel distances of 10,000km, resulting in slow, inconsistent, yet highly-groomed, sets when they push in. As the Woz only needs one day to run the event, this (theoretically) makes it a little easier to forecast the best swell-generating system.
So, looking across the South Pacific basin, there are a couple of swells due through the period, with one in particular standing out.
The first day of the waiting period looks to kick off with small, inconsistent levels of new S/SW groundswell, generated yesterday and today by a low firing up south-east of New Zealand (see image above). Now this is in Trestles' far, far swell window, with a patchy fetch of gales aimed northwards, producing infrequent 3ft+ sets for the first day of the waiting period, next Thursday.
This swell will fade with a couple of tiny days till what, at this juncture, looks like the best swell-producer for the event window. That being a flurry of strong polar frontal activity firing up south-east of New Zealand, before spreading further east.
This groundswell event which looks to last a few days will be generated by unfavourably aligned but strong, severe-gale W/NW winds stretching out along the polar shelf, south-east of New Zealand (see image below) later this week.
The elongated nature of the fetch will help prolong its lifespan, and we may see a trailing, better aligned fetch of severe-gale W/SW, winds forming on its tail, producing the most size. The models diverge slightly regarding this latter point so we'll have to keep an eye on it.
While not looking favourably aligned for California's swell window, the help of Great Circle paths and radial spread will see some good quality swell arriving from this source.
The initial pulse of S/SW groundswell emanating off the W/NW fetch should fill in on Sunday/Monday the 12/13th, providing infrequent 3-4ft sets across Trestles. Following this, the possible stronger pulse from the better aligned, W/SW fetch is due to arrive mid-late week, providing bigger 4ft+ sets.
Any storm activity that's due to follow the progression outlined above will form too late for any swell to arrive before the end of the forecast period.
Looking at the local conditions and, though a long way out, it looks like we're due to see local, offshore land breezes in the morning and fresh NE sea breezes, adding bumps but not writing off the surf completely. This will more than likely see competitors turn to the air into the afternoon. We'll sharpen up the wind forecast as the date approaches.
Similarly, for running updates on the timing and size of the expected swells, keep an eye on the comments below.