02 December 2016 - 10:36 • 13176 views

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A tropical low passing over the Kerguelens this weekend will once again be creating a major separation between the leaders and the chasing boats. This powerful weather system will be moving at thirty knots bringing warm air and colliding with the icy Antarctic breezes.

Hellish conditions are forecast east of the Kerguelens late this weekend and the entry into the Indian Ocean will be tough too. After a relatively quiet period between Brazil and St-Paul Island, conditions, which have tended to favour the two frontrunners on their way towards Cape Leeuwin, have returned to their usual pattern with a series of low pressure areas coming out of Argentina, to sweep across the Atlantic and out of Mozambique to dive down across the Indian Ocean.

The former are huge, deep areas, but moving at moderate speed (around 20 knots) with the main action centred around 50°S, while the latter are smaller, extremely powerful systems going diagonally across the race course between 30°S and 55°S bumping into the Mascarene High, usually located between Madagascar and Western Australia. They developed in the tropical heat, so the air mass is going from 25°C on the eastern edge as they develop to 10°C less than two days later. This thermal shock creates a considerable amount of energy over the sea which is at 3°C in the Furious Fifties, leading to a column of rising damp air with violent cold fronts. It’s like pouring boiling water over an ice cube…

The skippers are carefully watching how these systems develop in the Indian Ocean. For the two frontrunners, the risk is behind them. Alex Thomson and Armel Le Cléac’h (who has seen the gap widen with the black monohull on the starboard tack using her undamaged foil, are moving quietly towards Australia propelled along by the tail of a low pressure system, which should accompany them to Cape Leeuwin, even if they will probably have to carry out a lot of gybes off the SW tip of Australia.

Stir it up in the Kerguelens

For Sébastien Josse, in third place, 600 miles back, the configuration has been favourable for 24 hours after losing a hundred miles or so on Wednesday, as he made up for these losses during the night. Taking advantage of a front, he passed a long way north of the Kerguelens without encountering too many difficulties around the continental shelf as he was averaging more than 21 knots. The skipper of Edmond de Rothschild will also get ahead of this tropical low and is likely to gain back some ground from those ahead of him. As for Jérémie Beyou and Paul Meilhat, they are going to have to work hard to get to the eastern side of the low, as otherwise they will encounter 35-40 knot easterly headwinds in nasty seas… The problem is that ahead of this system, there is an area of calms being pushed along. So they have to avoid getting stuck there to avoid getting hit by the storm that follows.

Yann Eliès is the only skipper to find himself exposed to this tropical low. 700 miles from the Kerguelens, he is heading downwind north-eastwards on the edge of the calms in front of the storm. He will probably try to pass it getting away from the Antarctic Exclusion Zone to let the system go by and then hang onto its western edge with its powerful SW’ly winds. He should be able to cope with these winds, but the sea state may slow down his progress eastwards tomorrow evening…

As for the other four in the Indian Ocean, they will be spared by this phenomenon, but Jean-Pierre Dick, Jean Le Cam and Thomas Ruyant will be watching their mirror, as the Argentinean low, which fuelled the pack last night will be reaching them tonight with a strong NW’ly air stream, which will force them once again to sail along the limit of the exclusion zone towards the Kerguelens.

Those in the Atlantic do not have the same problem… Now that the cold front has affected them one by one, they have to find their way towards the Cape of Good Hope, which is not that easy in the light westerlies associated with a transition, before a new Argentinean low moves in. This should affect them at sunset; firstly Rich Wilson, Éric Bellion and Romain Attanasio before concerning the pack, where six skippers are battling it out within a hundred miles of each other…

There will be plenty of manoeuvres to carry out in the coming hours in this 10-knot westerly. The wind is set to strengthen as it veers to the NW and will reach 25-30 knots or more as the new front moves in… This is fast moving and once again, they are going to have to deal with a sudden wind shift under threatening clouds and winds in excess of 45 knots, before the situation stabilizes and they enter the Indian Ocean. Now, the pack and those chasing them (Pieter Heerema 350 miles back, Alan Roura and Enda O’Coineen 450 miles further west) will not have much time for resting, as a series of lows pass over them two days apart from each other over the coming week.

This deep low from the Tropics, which is creating the problem in the race course in the Indian Ocean should lead to us seeing a fleet separated out with the two leaders out in front, followed by one isolated skipper and then another pair. But 1500 miles back from the leading pair, Yann Eliès is likely to be the most affected by this weather depending on his options off the Kerguelens.

Dominic Bourgeois/M&M