(siento lo del inglés)
interesante reflexión de Andrés Soriano (con "Willy" Altadill en el neutrógena)
Posted on June 11, 2014
We all know the weather man has both his good days and his off days… When he gets it right and it benefits us, then we praise him, but when he is wrong, he is often the subject of words not suitable for repetition.
Out here, the weather variables are constantly changing but we rely on a few different tools to help us choose the best route through whatever weather comes our way.
The first and often the most forgotten tool is the barometer. Most of you that have some fancy watch with multiple sensors, one of which is probably a barometer. This measures atmospheric pressure and can give you a general sense of how the weather is changing in your area. As the barometer rises, it can mean sunny, clearer days. Its dropping indicates the opposite and it is particularly important to watch the rate of drop as that can show how rapidly the weather is going to change for the worst. Weather gurus will tell you it is not that simple, but I want to provide a quick, general understanding of it.
Often tucked up in the comfort of your own home, you turn on the Weather Channel to plan the weekend ahead. Well every few hours we do the same, except without the TV, and the creature comforts
. There are three major weather services we look at each with its own
‘weather model’. These are available either every six hours or every 12. We have software with which we can select the area of interest - at the moment we are downloading information just east of the Azores and laterally about 50nm past Barcelona. This is larger than we need but with weather systems it is important to see the ‘big picture’. This weather file is downloaded and loaded into the boat’s navigation software. Here we can run an animation showing how the weather unfolds relative to our track.
From here it gets slightly complicated…
This software has the ability to calculate the optimum route we should take. This is based on numerous factors. The first is the latest weather model we’ve downloaded, (or as many different weather models as you download).
The second are the ‘boats polars.’ Every boat has its own unique performance characteristics and the expected speed of the boats for every given wind speed and angle can be plotted on to a spreadsheet, known as the polars. This software looks at the route we want to take and shows us the quickest way to get there comparing the weather data with the ‘polars’.
Ultimately you have to realize this is just a prediction and the weather forecast is rarely likely to be 100% accurate, which is why it is important to sail first and foremost with the conditions that you currently have, regardless of what the routing might suggest.
Currently our weather routing suggests we’ll reach Gibraltar tomorrow, but after that conditions in the Mediterranean look far less predictable. The wind funnels through the Strait with some strength before lightening up and becoming quite unpredictable up the Spanish coast. This will become a game of snakes and ladders with the potential for many miles to be won and lost.
So far our two skippers have been doing an incredible job of deciphering the ever changing weather and the race is certainly not over yet.
Stay tuned… it will continue to be one hell of a race, right to the finish…
Andrés Soriano