The Offshore Voyaging Reference Site

Don’t Forget Weather Maps

I have to confess that, now we are no longer cruising offshore, I have tended to get my weather information from Windy and call it good.

But I just realized that that lazy approach was resulting in me losing the strategic and tactical feel for the weather I developed over some five decades of observing it closely.

So this morning, for the first time in months, I took a look at the excellent weather maps produced by our friends to the south—thanks to all you US tax payers—and was immediately reminded why doing that pretty much every day before looking at raw-model output—that’s what Windy is, just prettied up—is way better.

All the reasons for looking at forecaster-drawn maps are beyond the scope of a tip, but the most important one is that applications like Windy do not show fronts, and if we don’t know where the fronts are, and how they work, we are just plain weather-ignorant—fronts are where most of the weather that can hurt you lurks.

To learn more, we have an Online Book. The parts about how to download the weather are out of date, but the strategic and tactical method that kept Phyllis and me safe for so many years is timeless.

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James Greenwald

The list tends to be over the top for your average passage/weather planner. There are of course the main charts. The most weight given to the 500mb current/ analysis and NOAA surface ocean weather charts.

Michael Jack

Thanks, John. I start with the UK Met Office surface pressure charts every day, then go to a more local forecaster like the Swedish, Danish, or Norwegian services, and then I go to Meteo Blue which is a spin off from the University of Basel and has just about every piece of weather information imaginable (well the paid version does for 50 Euro/year) and so many models (if you think that is useful) including their own. That is onshore. Offshore, I haven’t decided yet, but one of your members (via an article by you) suggested Weather Routing Inc. which I have tested and I believe out of all the services has both the best service (run by meteorologists) and the best software (which I think conforms to your main requirements for offshore software). I find it still a bit buggy but what isn’t? It is also the most expensive of all.

Michael Jack

Thanks, John. Being the relative novice here, I probably over-engineer everything (like I did when I built a shed in my back yard in Belgium that could withstand a hurricane…we don’t get many of them in Belgium). So, when you say things like look at the surface pressure charts, I do it religiously. Btw, when I was referring to Weather Routing Inc, I was referring to their weather software like Windy rather than their weather routing service (which I haven’t used yet but might). Their offshore software (called WRI Onboard) allows you to select any three items at the same time including your requirements of “pressure, surface wind, and rain”. But you can select quite a few other items as well such as gusts, cloud cover, and snowfall. Anyway, I am still testing it and as I say, it is expensive.

Michael Jack

Understood, John and when I read your weather book previously I saw your comment and although I have not an ounce off the experience you have, I decided that weather routing software was just one algorithm too far (like you, I have (and still do) work in the software business so know the limitations). I did have one question for you, if you care to answer, as I sit out a storm in Tanager near Stavanger. What is the highest wind/sea combination you would intentionally go out in?

Michael Jack

Makes sense and probably was a silly question. I just like to get as much context as possible. Thanks for the links.