Global Solo Challenge - Weather information on board a sailboat
by Global Solo Challenge 30 Oct 2021 04:53 PDT
Approaching Cape Horn heavily reefed © Global Solo Challenge
Every skipper, whether on a sailing or motor boat, must always have a clear idea of the current weather situation and the expected forecast.
Before leaving port, at least it is advisable to listen to the weather report broadcast continuously on VHF channel 68 or the relevant channel in your country. If you sail abroad, find out about the reference services in the country you are going to.
Even before arriving by boat you can keep an eye on the development of conditions via the internet. Even on the quay on your laptop, ipad, iphone or other smartphone, you shouldn't ignore this source to stay up to date. Remember that a forecast is just a forecast and it is perhaps superfluous to say that the conditions you will encounter may be different!
Acquire an overview
When looking at the forecasts, don't focus exclusively on your navigation area and on too narrow a time window. Try to get an overview of the previous and next weather evolution for a large area around you. This is because while the forecasts are fairly accurate overall, the real weather could be slightly ahead or behind. A depressive centre could pass a little further south or north bringing very different conditions.
The first step would therefore be to view the synoptic maps with the current situation and subsequent forecasts. From here you can quickly check if there are any important weather systems approaching. In particular, warm or cold fronts with associated precipitation and probability of sustained winds.
Synoptic and weather maps
You can view the synoptic maps of your country on your national forecasting website, I also recommend using the maps developed by the British meteorological service, MetOffice, which enjoy an excellent reputation for their readability and cover all of Europe.
The interpretation of synoptic charts
Synoptic charts require a bit of habit and knowledge to interpret them. A meteorology course or a book can help you understand better but with a little patience you will also find plenty of online resources. It is only your curiosity that will get you to understand them: The basic principles are not very difficult.
The synoptic maps are a graphical representation of atmospheric pressure but also contain a lot of additional information. The difference in pressure between two areas is what generates moving air flows, therefore the starting point for understanding the movements of the air masses. You will also hear about warm and cold, occluded and stationary fronts and stable and unstable air masses.
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