So, Singleton’s Golden Rules:

There are no quick answers, no short cuts

Weather does know not itself to Beaufort +/- 1

Better to be in port wishing you were at sea than at sea wishing you were in port. Using planning forecasts carefully minimises chance of being in a place that you do not want to be in, in weather that you do not want to go out in.

NEVER, EVER go to sea without studying SEVERAL forecasts.

NEVER stop monitoring the forecasts

 

There are things weather forecasts can do for the yachtsman; and things they cannot. They are not precise because, although complex computer models are used, they are based on dividing the earth's atmosphere up on a three-dimensional grid (rather than treating it as a continuum) - so that, for example, the global computer model run by the Met Office cannot take account of features smaller than 80-100NM. This, and other approximations, limits the detail that can be modelled so that even today's computers lack the power to make a complete analysis of the atmosphere. Also, the quantity and quality of the data are the sources of further uncertainty. The global model can be interfaced with a meso-scale model , based on the British Isles, to get more detail but the consequnce of all the uncertainties is forecasts that are good in general over the following 2 to 3 days but rather poor in detail for the following 12 hours. It is here that the local knowledge and experience of the human forecaster comes in.

For the cruising yachtsman there are really three key questions. Is a weather windo opening or closing? Is bad weather expected? Where do I want to be if it comes?

To answer them there are a number of sources of information:

synoptic charts downloadable from several providers
NAVTEX extended outlook
HF/SSB radio plus laptop or, for example, the NASA Weatherman for data and charts
US GRIB (gridded data) files that can be used to produce a variety of weather charts
Marinecall or Metfax

Frank recommends using more than one source and comparing the results. The key is to watch trends and make provisional plans that can be fitted to the forecasts.

If you are planning a passage of less than 24 hours there are many more tools available: the BBC, NAVTEX and the VHF inshore forecasts. You should listen and watch everything available and aim to identify trends in the weather. And this shouldn't stop when you set off: keep monitoring the conditions and forecasts by all the means at your disposal.

 

 

 

 

 

 

 

 

 

 

 

 

 

Sailing is about being out in Force 2 to 5 as far as possible. Force 6 and 7 are not disasters. You certainly want to avoid 10!

More information is available on Frank's well-known web site: www.franksingleton.clara.net

Summary by Geoff Meggitt and Carol Sparkes