• Going if you are unsure too often leads to mistakes.
  • … train yourself by looking at forecasts even when you are not going afloat as this makes it easier for those days you do go out.
  • The sign of a good skipper is knowing when to say no.

The summer of 2018 saw weeks of sunshine with little need to check the forecast before making a decision on whether to go afloat. But we are not always so fortunate. Paul Glatzel considers the difficult decision that sometimes needs to be made ‒ ‘weather’ (or not) to go …

One of the most difficult bits about boating for most skippers is knowing when to go afloat or when the weather or the forecast suggests a day missed would be the best idea. In this article we’ll have a look at how experienced skippers will think through the weather and make the decision as to whether to stay or go.

If you really want to understand the weather, it’s a science, and you can spend hours, even weeks, trying to understand what causes it, how weather systems are formed and things like the names of each of the cloud types. For us as leisure boaters in smaller boats, while we can certainly have fun getting to know some of that, what we really need to be able to do is interpret a weather forecast and understand how that will impact on our boating, and thus whether we should go afloat or stay ashore.

For me, the first thing I do when looking at a weather forecast is to think about where I intend boating, as this will have a major impact on what I look at and how many different sources of weather forecasting I check.

If I am boating within the confines of an area like Falmouth Harbour, or the sheltered areas of Plymouth Sound, the type of forecast and the number of forecasts I look at will be very different to if I am aiming to head off to the west coast of Scotland or down the east coast.

Generally, the first forecasts I look at will be the simple, visually friendly forecasts you find on apps or sites like XCWeather, the BBC website, the Met Office and Windguru. Personally, my first ‘go to’ app is XCWeather, because it is so visually simple and you can configure it to show wind strengths on the Beaufort Scale (more of which later).

If all these forecasts are saying much the same thing, that’s really good news and it should allow me to make an initial decision. If it’s clearly good weather or within the capability of the boat, then great, but if it’s not good or marginal I will need to start to look at things in somewhat greater depth.

This is particularly so if I am going to be boating in a more challenging area or where I am more exposed with less backup. 

My next source is the Inshore Waters and Shipping Forecasts. These are dedicated marine forecasts produced by the Met Office and cover either really large areas, including a long distance offshore, and so are very general (the Shipping Forecast), or a section of the coast up to 12 miles offshore (the Inshore Waters Forecast).

The challenge when looking at these forecasts is that to properly understand them you need to be bilingual. You need to speak English and weather.

Inshore Waters Forecast to 12 miles offshore for the period 0600 UTC Thursday 31 January to 0600 UTC Friday 1 February 2019. General situation: A slack pressure pattern affects the eastern coasts today, as an Atlantic low moves towards Biscay today and tomorrow, bringing gales, rain and sleet to the south coasts. Lyme Regis to Land’s End including the Isles of Scilly ‒ strong wind warning. 24-hour forecast: south-easterly, becoming cyclonic, then north-easterly later, 5 to 7, occasionally gale 8 at first. Slight at first east of the Lizard, otherwise moderate or rough, occasionally very rough later in far west. Showers, rain or sleet for a time. Good, occasionally poor.

The first paragraph states when the forecast was issued. This is really important as any references in the forecast to when weather systems or wind changes will occur refer to this time. You can see it was issued at 0600.

The second paragraph just gives a general overview, while paragraph three drills down into the specifics of what is happening in that area from the issue time to 24 hours later. 

The reference to needing to be bilingual is proven in this paragraph. What does ‘cyclonic’ mean? It actually means there will be great variation in wind direction. ‘Later’ refers to a set time after the forecast issue time – 6 to 12 hours after the forecast time. ‘5 to 7’ refers to wind strength on the Beaufort Scale. ‘Rough’ refers to a specific wave height of 2.5 to 4 m, and so on. If you are not bilingual, the forecast may give you a rough idea of what’s going on, but not the full picture. Remembering every definition isn’t easy, but most importantly, if you know the forecasts are full of words with specific meanings, then an almanac will give you the definitions, and so does the Met Office website.

If you are going further afield you are going to need to look at the weather for your departure location, where you are going and of course the bit in the middle. This may mean you need to look at quite a few forecasts. If I am going further afield I will also look at the Synoptic Chart for the area. A synoptic is a weather map and shows the weather systems, and so can predict the weather coming into your area. I am always particularly interested in weather that’s headed my way but not predicted to arrive until after my intended passage, as in my experience occasionally this weather system arrives earlier than predicted. A synoptic gives you this high-level overview of what’s going on. There are plenty of places to see synoptics and many now are whizzy and full-colour animated things, but my preference remains the black and white Met Office version from a website at www.stronge.org.uk. Again, this won’t make much sense unless you understand more, so a good book to refer to is the RYA Weather Handbook to better learn about weather and how to read forecasts.

So, you gather all this information, and then what do you do? This is the difficult bit, as while often it’s clear one way or the other whether you should go, the challenging decision is of course when you are a bit unsure.

A good rule of thumb is that if you are less experienced and a bit unsure, then don’t go unless you are doing the passage alongside someone more experienced and knowledgeable, and so able to help you with the decision. Going if you are unsure too often leads to mistakes. If you are experienced and unsure, that experience should guide you, and again an uncertain feeling is a good indicator that you should stay ashore or limit your passage. The sign of a good skipper is knowing when to say no.

In summary, weather can be something that you have a passion for understanding, or a pot of data you need to interpret. Whichever it is for you, train yourself by looking at forecasts even when you are not going afloat as this makes it easier for those days you do go out.

Have fun and fingers crossed for the summer of 2019!

The RYA Powerboat Handbook is available for £16.99 from the RYA shop.  It is also available as an e-book using the RYA app.  

Paul Glatzel is an RYA powerboat trainer and examiner and is based in Poole in Dorset. He runs Powerboat Training UK and is the author of the RYA Powerboat Handbook and the RYA Advanced Powerboat Handbook.

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