Light, upwind Rolex Fastnet Race

A look at the weather models for this Sunday's race

The Rolex Fastnet Race gets under way this Sunday, 9 August with the first warning signal at 1150 BST. Looking at the US and European weather models for the start, both are agreeing that it will be light, the early starters such as the IMOCA 60s and the smaller IRC classes, struggling against the tide flooding in up the Solent from the west. The tide begins to turn on the island side by 1245 and is fully ebbing by 1315.

The overall weather situation at start day has the northeast side of Azores high encroaching on the south coast of the UK with a depression out in the Atlantic. The two models differ in how developed this depression is, the European model suggesting that it is fully spun up and very much more intense than the US model indicates.

Come Sunday night both models still agree that it is light on the Fastnet race course, which is just being touched by the furthest southeast reach of the depression with the wind light and in the west.

Both models agree that the westerly wind will build over the course of Monday morning but only to 10-15 knots and still on the nose, from the WSW, the boat sailing into more breeze the further west they are.

By Monday night both European and US models have the depression centred to the north of Scotland and both models have the wind picking up to 15-20 knots, the difference being that the evil European model has the wind veering around more to northwest in the Celtic Sea, so still on the nose for those boats that have passed Land's End by this stage. The US model has the wind more westerly, so at least a fetch to the Rock.

By midday Tuesday the depression has moved north on both models and the race course comes more under the influence of the high that has and still is off to the southwest throughout this period. The difference between the models is where the 'edge' of the high is - thus the US model has it in the Bay of Biscay, thus evil northwesterly up to the rocks, whereas the European model has it further north, thus more favourable WSWerly winds in the Celtic Sea.

Coming Tuesday there is more agreement between the models in terms of the wind direction at the Rock - both suggest westerly but once again the European model is showing more pressure, around 20-25 knots. There is again differences of opinion over the shape of the eastern end of the high with the European model showing WNWerlies at the Lizard while the Americans believe it to be more NNW.

So in short a relatively typical Rolex Fastnet Race with challenging conditions: pitifully light at start and then upwind all the way to the Rock at which point there will finally be reprieve. At this stage it is hard to say whether it will be a big boat or a small boat race - the big boats will benefit from sailing into building breeze along the south coast and also probably won't have to kedge in the light wind on the first night, while the mid to smaller boats will benefit from a fetch rather than a beat up to the Rock.

12 hourly interval weather charts on page 2....