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Around the horn at last! With the Southern Ocean out of the way, the race is over ... right? Wrong! The leg up the Atlantic will prove the making or breaking of front-runner Michael Desjoyeaux as MacArthur and Thiercelin nip at his heels January 10, 2001 Just as we predicted, consistent westerly winds from a slow-moving low pressure cell deep in the South Pacific, have propelled leader Michael Desjoyeaux to a 500 mile lead over his nearest rivals. For the last week, Desjoyeaux has maintained a faster boat speed and has increased his lead by 400 miles thanks to the ultimate piggy-back ride. For Ellen MacArthur and Mark Thiercelin - second and third respectively - (Roland Jourdain has slipped back with halyard problems) the ride was short lived. They literally fell off the back of this low pressure cell, and are languishing (how can you languish in the Southern Ocean?) in a trough of weak low pressure immediately behind the slow-moving low and another frontal system moving in from the west. MacArthur's situation is remarkably similar to what occurred around the Kerguelen Islands, when she and Thomas Coville sailed in moderate conditions - again in the middle of a weak low pressure trough - while second-placed Desjoyeaux and third-placed Roland Jourdain caught the low in front of them, with south west winds circulating around its western flank, and accelerated to a marginal lead. Southern Ocean slow down How can you catch a low pressure cell in the Southern Ocean? To be honest, it has rarely been done in a monohull before. Clipper ships and Downeasters were known to stay with a slow-moving system for three days at a time, averaging 17-20 plus knots, but never for a week! Of course, the modern Open 60 monohulls are the fastest of boats behind modern multihulls. However, the big factor at the moment is the slow, meandering nature of weather systems in the Southern Ocean. Since the fleet front-runners entered the deep south in early December, things have been slow and easy compared to previous Vendee Globe races. Right across the southern Indian Ocean, the leading skippers kept pace with the weather, often caught in lighter winds between two low pressure cells. Of course, those behind - traveling in a different weather system - reported winds above 60 knots in squalls. Under Australia and New Zealand things really slowed down and the jet stream tracked south then north then south again, keeping high and low pressure cells beneath it caught in swirling eddies. The South Pacific could have been just as convoluted, had the fleet reached it sooner. But as it turned out, the South Pacific proved plain sailing for the leader, and frustrating for those in second place. The jet stream smoothed out, tracking west to east and a constant stream of westerly winds circulated over the top of that slow-moving football-shaped low we mentioned earlier. Around the Horn Now the fun begins, with skippers entering a region of notoriously fickle winds to the east of Tierra Del Fuego. As Bob Rice explained in his guide to global weather routing, the high Andes are known to sheer low-pressure weather systems approaching from the west, cutting them in half and allowing only their upper level winds to pass to the east. At the surface, the result is a balloon of high pressure developing out into the South Atlantic towards the Falklands. Picking when to cut the corner, or choosing to sail around the bubble of high pressure is a decision sure to weigh heavily on the minds of those in front. After all, in the last Whitbread, second and third-placed yachts - including Grant Dalton's Merit Cup - wallowed in light airs while those lagging behind literally sailed around them to capture a place at the podium in Sao Paulo. Beyond the Falklands, there remains a tricky trough of low pressure, extending east-southeast from the coast of Uruguay. Picking a route through this fickle region will be a true test of weather skills - something in which Desjoyeaux is well qualified (they don't call him the professor for nothing). North of the trough lies headwinds circulating around the western side of the St Helena High, and beyond that the doldrums. The race is far from over!
South Atlantic pressure
Image courtesy of Ocean Weather The westerly air flow in the Southern Ocean is forced north along the west coast of South America in this pressure map. Off the east coast of Uruguay, and the mouth of the River Plate, lies a trough of weak low pressure and a region of variable and light winds. This is the area which could make or break leading contenders in the Vendee Globe. Note the St Helena High east of Brazil, and its associated northerly winds in that corner of the ocean.
Five day wind forecast for the
Atlantic This US aviation model (AVN) is predicting a low to emerge out of the band of low pressure off the Uruguay coast within 48 hours and move quickly to the east, with westerly winds in its wake. No doubt the Vendee front-runners will be keeping a weather-eye on this one! Variable winds during the low's formation have the capability to slow leader Desjoyeaux, while westerly winds in its wake might help those further behind. However, these models are not very good at predicting stalling weather patterns, and when you look 96 hours in advance, there is plenty of room for error.
Southern Ocean jet stream This chart shows the path of upper level winds while Desjoyeaux rode that slow-moving low pressure cell all the way to Cape Horn. With the stream nice and straight, there was little chance for blockage. Southern
Ocean jet stream Now the jet stream is starting to meander, as a new low develops to the west of Cape Horn - indicated by the blue and red lines (cold and warm fronts closer to the surface). As a guess, winds in the lee of Patagonia should be affected by this jet steam meander.
Fleet positions Desjoyeaux in red is streaking ahead of his rivals, thanks to the steady south-west winds flowing around a slow-moving low to his south. MacArthur (in blue) and Thiercelin (in orange) are caught in moderate winds, part of a ridge of high pressure preceding a strong frontal system. Fleet positions Three days ago Desjoyeaux began a long sprint ahead of his rivals thanks to that low pressure cell, while his rivals 'languish' in a trough of low pressure. Pictures courtesy of Virtual Spectator.
More great reading: Vendee Globe Race headquarters Michel Desjoyeaux's home page: Steady as she goes, professor! Ellen MacArthur (Kingfisher) : She refuses to give up, despite losing her only gennaker Roland Jourdain's home page : Read about his disappointment at losing second place due to gear failure. Re-live the Sydney to Hobart yacht race! Break ice in the Ross Sea! Coment from Ellen MacArthur (Kingfisher) : "As I sit here and type I am cold and wet - wet with my own
chilled sweat. It was a busy day once again weather study, and many,
many sail changes as the wind slowly turned, and fluctuated in it's normal
Southern Ocean way. By Sunset I had the gennaker up, and was
sailing in about 15-20 knot of breeze. There were squall clouds
around, and as I had the gennaker up I was worrried that if I slept inside
for a while I may be to slow to get to the auto pilot, so I piled on the layers
of clothes, and as best as I could tried to keep warm in the cuddy.. I put
a spare oilskin over me to try to keep warm, the water temperature here
is warmer, so it wasn't as cold as it has been. I was just drifting
through a another series of dreams, when the heart stopping slowing of
the boat happened, and the grim realisation that we had once again blown
the gennaker halyard,,,, no sail, nothing - just a chafed through halyard.
The gennaker - our only gennaker was lying over the waters surface.
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