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No shortcuts here! Between the doldrums and the westerly winds of the Southern Ocean lies the South Atlantic High, and for the three leading cats in The Race there appears to be no choice but to sail all the way around it ... January 13, 2001 The south-east trade winds below the Inter-Tropical Convergence Zone have provided the three Gilles Ollier - designed cats with a real kick-along. Team Adventure - now the leader by two miles - has dueled at high speed with Club Med recording 572 miles in 24 hours during January 11. Club Med responded with 532 miles in the same period. Not a record, but very impressive considering the average trade-wind conditions. What lies ahead offers less plain sailing and more head scratching for weather routers Roger Badham (Club Med) and Ken Campbell (Team Adventure). Dominant high pressure According to the US aviation model (AVN) for South Atlantic wind pressure, there appears to be no way to 'cut the corner' of the South Atlantic High as we described in the last Race bulletin on December 10. Indeed, routers and on-board navigators may have to hug the South American coast all the way down to 35 degrees before this high pressure cell will let them slide to the east. A low pressure cell formed off the Uruguay coast on December 11 and was forecast to slip eastwards, pushing into the South Atlantic High and might have aided The Race leaders by providing northerly winds ahead of that low's frontal cloud band. But the high pressure cell proved too strong, and the low has slipped well south, now centred over South Georgia. While the storm's frontal cloud band is extensive - it reaches all the way north into the Amazon Basin, winds running southwards along its eastern face are confined to the far western edges of the South Atlantic. Complications arising To make matters more complicated, there appears to be a separate bubble of high pressure developing to the west of the dominant South Atlantic high. Instead of one high pressure system generating winds around a tight centre - and offering yachts the opportunity to sail further east, we have two high pressure 'centres' (really just a blob of weak and variable winds) stretching right across ocean. Look to see Club Med and Team Adventure try to sail between these two high pressure centres, but if NOAA's model is correct, there is every chance these two bubbles of high pressure will merge, creating light and variable winds from coast to coast. If Innovation Explorer - furthest to the west - holds her course and sails around this mess, she may find better conditions. On the other hand, if the two leaders successfully sail through the high pressure centres, they could see themselves well-placed to lead all the way to Cook Strait in New Zealand and beyond. Meanwhile, don't count on a 'round-the-world record being set in this global race. Routers can't always choose the best course because the competition makes other demands. But neither will these fast cats have to worry about mouldering in the horse latitudes. These boats are fast all the time. After all, they are the future of sailing! © weather-wise.com 2001 South Atlantic pressure South Atlantic pressure, derived from the US aviation model (AVN) shows two high pressure centres stretched across the South Atlantic from Uruguay to South Africa. Expect race leaders to attempt to sail between the two centres, to save miles. But if the forecast is correct, these two centres should merge with light and variable winds from coast to coast. Those that can successfully sail through this region will come out ahead before they reach the westerly winds of the Southern Ocean. Image courtesy of Ocean Weather. Fleet positions Picture courtesy of Virtual Spectator. Team Adventure (orange) and Club Med (blue) battle for the lead while Innovation Explorer (green) hangs off their right hip. You can see here that Innovation Explorer's decision to go west through the doldrums, as we discussed last time did not pay dividends. The South Atlantic High is spreading its influence from coast to coast right now, posing problems for weather routers, hoping to cut a corner and save valuable miles. Five day wind forecast for the
Atlantic
If you believe this model, the South Atlantic high will offer few opportunities for skippers and routers to 'cut the corner' on their way south.
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